Find answers to Frequently Asked Questions for First Generation Firebirds that have been asked and answered on FGF. Special thanks needs to be given to all the FGF members who took the time to respond to other member's questions.
Transmission and Clutch - Transmission
Refer to 1968 Pontiac Service Manual, Section 7E, page 7E-30
Reference:
- 1968 Pontiac Diagnosis Manual
Q: 3-Speed Turbo Hydra-Matic 400 vs Powerglide
Does anyone know if I put a turbo 400 tranny in my 1967 firebird if it would have a lower end than my powerglide. How much? Is it worth it. I have 326 H.O. in the car. Any help is appreciated.
A: You’ll have to change out your transmission cross member for a 400 unit (available from resto parts catalogs). A cheaper solution would be to go with a short tailshaft Turbo 350. It would be plenty strong enough for a 326 and will use the existing cross-member. The gear ratios of the transmissions are as follows:
Power Glide 1st-1.76; 2nd-1.0
Turbo 350 1st-2.52; 2nd-1.52, 3rd-1.0
Turbo 400 1st-2.48; 2nd-1.48, 3rd-1.0
As you can see, the real benefit is in the extra gear for acceleration (lower first gear plus the added second gear). Because, the final gear ratio is 1.0 you’ll get no benefit at the top end. You’ll have to decide if it’s worth it. Me, personally, I’d go with a 2004R and gain overdrive.
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Content last modified: January 20, 2014 at 10:06 pm
Q: Auto Transmission Removal
I’m swapping my Power Glide to a Th350 and I’m having some trouble. I’m sure the pros are going to think these are dumb questions, but hey, you learn by doing.
How do you get the rear cross member out? Do you have to loosen up the frame rails? It can twist (pivot) to a point before it hits the floor pan and gets stuck. How do you remove the top 2 bell housing bolts? Do you remove the dipstick first? How do you remove the transmission oil cooler lines at the trans.
A: This may sound unorthodox but I slide one side of the cross member as far forward as I can then just use a hammer to tap other end clear towards the rear of the car. If yours is a real show car then you may have to loosen the frame mounts. After you remove the cross member, you can then tilt the motor and tranny with a jack to gain better access to the top two bolts (use a LONG extension and a flex socket). When tilting, watch out for the distributor against the firewall. By tilting, it’ll also help with the trans lines. I think you can take the transmission lines loose from the radiator and unbolt the retaining clip from the oil pan and lower them with the tranny to gain better access. You may have to go up and down with the transmission a couple of times to first remove the retaining bolt then to remove the filler tube.
A: (How do you remove the top 2 bell housing bolts. ) 9/16 shallow flex socket with 3 ft long extension on 3/8 ratchet.
(Do you remove the dipstick first?) Only if you want all the fluid to come out. Use drain pan under neath and loosen the pan leaving 2 bolts loose in front with the rest of bolts removed.
(How do you remove the transmission oil cooler lines at the trans. ) Use a flare nut wrench, with a backup wrench on trans fitting.
Theres an article on a ST300 to a 2004r in a 1967 Buick A body in Aug issue of Hot Rod. Might help for a few tips and really helps for anyone doing the ST300 to 2004r or 700 conversion.
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Content last modified: January 20, 2014 at 10:07 pm
Q: 2-speed Powerglide to 3-Speed Turbo Hydra-Matic 400
I am putting a 455 into a 1968 Firebird. It currently has the 2-speed in it. I bought a turbo 400 to put into it. Does the support need to be change? I was told it did not. Also would a 2004a hold up to this motor. How much does it end up costing by the time you get it in?
A: Yes, you will have to change the transmission crossmember if you go with eithre a Turbo 400 or 200-4R. A Turbo 350 will bolt in. The cost of the 200-4R is greatly dependent upon how much you pay for the transmission to start and what you want it to do. If you are just going to run it on the street (read: not street drags) then a stock unit in good shape will last a long time. If you plan on abusing the car as in racing you will want someone to bullet-proof the unit (read:$$$). The archive files discuss this more. I also recommend you get hold of a copy of High Performance Pontiac, April 98 for some good insite.
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Content last modified: January 20, 2014 at 10:08 pm
Q: Converting from Powerglide to TH350
I want to convert from Powerglide to TH350.
1. For street, non race applications, is the 3:32 to 1 rear end a good choice? My car really suffers from lack of low end power.
2. Is it true that I just need to change from a type 2 to type 3 carrier. I don’t need to change the axle assembly?
3. Since I’m changing to the TH350 and a type 3 carrier, can use my existing drive shaft?
4. Where can I get a 3 speed console shifter? Do I really need to change this as it just another detent position.?
A: 1. SInce you are changing to a TH350 you’ll be gaining an extra gear. Both the PG and TH350 have a 1:1 final ratio but the TH350 has the benifit of a lower first gear. The 3:32 gear is a good comprimise between performance and econimy. You will notice a big difference.
2. No. The existing rear-end will work great if you keep the gear set you have.
3: The TH350 is a DIRECT swap for a PG. the only thing that you need to change to make it totally correct is the detent in the shifter. But, it isn’t necessary. Some have just used a file to add a extra detent for the extra gear.
4: No (see above). But, if yo decide you need one, ask the F-List first. I have found them to be very helpful and honest.
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Content last modified: January 20, 2014 at 10:09 pm
Q: 200R4 or 700R4
I just purchased a 1968 firebird convertible with a 428 from a 1969 grand prix SJ and a Turbo 400. I am considering replacing my Turbo 400 with either a 200R4 or a 700R4. Any advice/suggestions would be greatly appreciated. Obviously, the car was not original/numbers matching to begin with so I hope I’m not offending any purists out there.
Thanks.
A: A couple of things to consider when making your choice:
2004r comes in a bolt pattern that will attach directly to the block and is almost identical in length to a 400TH. This makes the install simple with a 400TH trans cross member. It is considered weaker than the 700r4. If you pull a 2004r out of a Buick Gran National or Monte Carlo SS you’ll get a stronger unit.
The 700r4 is a stronger unit but will not hold up if you plan on drag racing. Either unit can be reworked to make them bullet proof if you have the bucks. The 700r4 will require an adapter ($40) to attach to the Pontiac block and you’ll have to move your transmission back on the frame about two inches. In both cases you’ll have to have your drive shaft shortened ($30).
The TV cable is tricky to get right. Thee are companies that sell TV brackets to mount to an intake but not sure if one is available for Pontiac (would be interested to hear from some one on this). I made the one for my buddy’s car. It holds both the TV cable and the throttle bracket but I have a Mig.
You’ll need a kit to convert the trans to a non-computer controlled unit. I recommend a company called T.P.I. Tech (1-203-599-0382). They have a conversion kit for about $70 and it works great (no switches to flip to go into or downshift out of O.D.).
You can use a stock shifter but you’ll need to purchase a decent kit ($60). The trans yoke from a 350TH will fit directly into a 700r4 (not sure about the 2004r) If your car originally came with a 400TH or you have a rear end from a car that did, it has a large yoke (make sure you have the correct trans yoke).
Over all, it’s not that expensive to do and the way these big cube motors suck the gas, your pay-back is pretty quick if you drive a lot. I’m planning on installing one behind my 400 when it starts to go back together. I’ve install a 700r4 in my buddy’s 1968 Camaro and it works great (300hp and 24 mpg highway on a 3.4:1 gear). Good Luck.
A: The turbo 200 is not a particularly strong tranny, the turbo 700 is, if you get a post ’86 version. The 700 is longer, so you will have to do driveshaft and crossmember mods to get it to fit, and possibly the floor pan. Get the yoke with the tranny.
A: I have a 1969 Ragtop with the same package and I’m runing a 3.08 posi rearend. Why would you want to convert to a 2004R? My car has enough torque to smoke the tires from here to kingdom come and it runs great on the hiway (13.7 in the 1/4). Though I did add a Holeshot 2000 torque converter to it. I would’nt mess with a good thing. That’s my 2 cents worth.
A: The 700R4 is the stronger of the two transmissions,however it is not anywhere near as strong as a turbo 400,particularly in stock form.This also applies to the 200R4. You should not even think of using either model without having it rebuilt & beefed up as much as possible.If you are real lucky or diligent you may be able to find a 700R4 with the “dual-pattern” case (ie-it has the chev & buick/olds/pontiac bellhousing pattern) I don’t know how rare they are but they do exist. As mentioned before, you also have to deal with shifter, driveshaft length, X-member etc. I would also install an external trans cooler to increase reliability.
A: No 700r4 came with the B-O-P pattern, only the Chevrolet pattern. The Monte Carlo SS only came with a 305, therefore only a 200 4r. Your best bet for a 700r4 is a late model Camaro/Firebird. As to “why” ans someone asked… you get a lower first gear and overdrive all in the same package. No you cannot drag race a stock 700r4 like you can a 400TH but most who build their cars for drag racing don’t do much highway cruising. I like to drive my convertible with the top down to a little town about two hours away. At 24 mpg versus 16 mpg it doesn’t take long to pay for the conversion. And with the lower first gear you can still burn the tread off of the tires if you feel like it.
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Content last modified: January 20, 2014 at 10:10 pm
Q: Powerglide (Automatic Transmission) for 1967
I’m in the process of (finally) getting some serious work done on my 1967 firebird – it’s been a nice cold Pennsylvanian winter. I have a 326 w/2bbl and when I get it rebuilt I’m putting the Carter AFB 4bbl on it (I have a correct Pontiac 4barrel intake from an HO.) My question is regarding the transmission. I have never driven a car with a powerglide and I was wondering if i could get a little bit of people’s thoughts on the transmission. I want to say right now that this car is my baby and will NOT be taken to the strip, but will be taken on some long trips. Is the powerglide reliable, and is it worth sending out to be rebuilt? (the trans runs, but I’m rebuilding it anyway ’cause I dont want to have to rip it out once the car’s together.)
A: The ‘Glide is a very good transmission. Its’ one real draw-back is it only has two forward gears. This isn’t really a problem but most of us are becoming more used to at least three (or more). The first gear ratio is numerically lower than that of a Turbo’ tranny because it’s a compromise. Let me try to explain: If it had a taller ratio in first you’d have a better hole shot but you’d have to wind the RPMs of your motor to keep it from stalling it when the transmission shifted into second (final). The final gear is the same as the Turbo’… 1:1. So really, it’s more of a drive-ablity issue.
Unless your car is a very special model or you are a purest, most people (whether driving or buying) prefer the 350/400 Turbo-Hydromatic for the above reasons. Hope this helps.
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Content last modified: January 20, 2014 at 10:11 pm
Q: Deaborn 3-Speed for 1968
My 1968 400 came with a Dearborn 3-speed transmission, complete with “FoMoCo” stamped on the case! The bell housing had two bolt-hole patterns already drilled. I helped a friend drop the trans in his 1968 Olds 442 — same thing.
I have heard this was due to a strike at Muncie plant, but did they even make a 3-speed? What is real low-down on this?
A: Another tall tale. Muncie/ Gm didnt offer a 3-speed that would stand up to the torque rating of the higher HP V-8s. So they chose a Dearborn”FORD” trans. All the more reason to order a 4 speed. BTW Most Chevy V-8s of that era didnt need a Heavy Duty trans Whats that tell ya??? Muncie did make a 3 speed but it was light duty. .Saginaw was the norm for all other 3-speed applications.
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Content last modified: January 20, 2014 at 10:12 pm
Q: Transmission Swap 1967
I was wondering if anyone could tell me what is involved in swapping a powerglide tranny out of my 1967 Firebird for a 400 Turbo or 350 Turbo — which would be easier? (Would I have to change cross-member, yolk, or drive shaft on either of these applications?) I would appreciate any input you would have for me on which would be the best to do.
A: 350 would be a straight swap. 400 will need a new crossmember and front driveshaft yoke and a shorter driveshaft. Depending on which year, the kickdown on the 400 will also be different. good luck.
A: I just did this swap in my 1967 convertible. The above was correct in everything it said, I also found that my two speed shifter had too much throw, so you’ll have to put in a 3 speed unit or buy a conversion kit with the proper detents and new linkage rod. At the same time you may as well replace the plastic indicator. This swap is well worth the effort, I really enjoy the extra performance of the 3rd gear. Good Luck! P.S. I got my cross member and drive shaft from Steve Hansen, who has been mentioned before in this forum.
A: I spoke with my local transmission shop who said that the Turbo Glide and the Turbo 400 are exactly the same. No modifications needed. The Turbo 400 requires a kick down cable from the carb., where the Turbo Glide uses an electric switch. That’s the only difference. Let me know how it goes.
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Content last modified: January 20, 2014 at 10:16 pm
Q: 6-speed Trans Modification
I want to install a 6-speed transmission in my Firebird since here in the Netherlands, gas prices are expensive. Is this possible?
A: if you want to install a 5 or 6- speed transmission, go ahead. I’ve installed a 700r-4 in a 1968 Camaro convertible and I love it. When my Firebird convertible goes back together it will most likely have a 2004-r or 700r-4 in it as well.
The benefit to an overdrive is highway mileage. If you spend a good deal of your time in the car at highway speeds, an overdrive will DEFINITELY improve your milage per gallon. With a 310 hp 350 CID and the 700r-4 in the 1968 Camaro it gets 24 MPG on the highway.
I’m sure American cars of the vintage we have are hard to come by where your from so I dought adding a 5 or 6-speed transmission would hurt it’s value. And, you could always keep the 4-speed and sell it with the car if you do sell it to a purest. I was at an auction last year and watched a 1969 Camaro convertibe that was factory stock looking on the outside and the interior but had an LT1 and 6-speed transmission sell for $26,000. It was a nice job.
As far as which transmission, look for on with the universal B-O-P bolt pattern. If you cannot locate one, you can use an adaptor plate to bolt a Chevy bellhousing to the Pontiac motor. I’ve never switched standard transmissions but I’ve seen a 1969 Camaro with a 5-speed with a stock console and would not have known it until the owner told me.
My advice is take carefull measurements. If you have to cut you tunnel, cut the area out without bending it using a thin bladed saw. Fabricate a patch out of other metal and save the piece you cut. If you want to go back to original the piece can be easily welded back into place.
Wish I had more technical advice but I hope this helped.
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Content last modified: January 20, 2014 at 10:17 pm
Q: Identifying a Transmission
Transmission ID question for a 1967 326 H.O. which has a 3 speed manual trans and I am looking for the manufacturer. The numbers are as follows GM 3925647 , F288 (cast on rt. side) and 18S273731 (on the oval boss rt. side). I don’t know if it is Muncie, Saginaw, Borg Warner ect…
A:
….F288 (This is the date-code: June 28th 1968)
…18S273731 (This is the VIN from the vehicle the Trans camein)
…1968-St.Louis
… Typically, a Muncie Trans would have something like the following stamped in it:
…. P7J25 (P= Trans Type: Muncie, 7= 1967, J= Oct., 25= day)
… Also, up until 1969 the Trans. Arm’s attached to the side w/studs & nuts
…. After 1969 the Trans. Arm’s attached w/bolts.
…. 3925647= Case Number for a 3-spd.
I’m sure there will be other’s who can provide more details on the 3-speed; most of my info is 4-spd related.
A: There were two different 3 speed manual gear boxes available on the 1967 Firebird. The “Standard Three-Speed Manual (Saginaw) Transmission” and “Heavy Duty Three-Speed Manual (Dearborn) Transmission”.
The Warner gear box was ONLY installed on Firebirds equiped with the 400 CI engine. All other Firebirds with three speed transmissions, (including the 326 HO), received the Saginaw gear box.
Unfortunately, neither the 1967 Pontiac Service manual, or Firebird Supplement Manual list the part numbers or codes. However, the information I provided above, comes directly from the Firebird Supplement Manual. So, if that is the transmission that came in your car from the factory, then it is safe to assume it is a Saginaw.
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Content last modified: January 20, 2014 at 10:18 pm
Q: Identifying Saginaw 4-speed or a Muncie 4-speed on a 1967
How can one tell *FOR SURE* if you have a Saginaw 4-speed or a Muncie 4-speed. How about if its a M21 close vs m22 wide ratio? I read somewhere that all 1967 4speed birds were saginaw-equipped (something about deloean and co having very little time to get the 1967 model out the door?) Did some 68’s also have saginaws?
A: They both have 7 bolts on the cover. The reverse lever on the Muncie is mounted IN the extension housing, where the Saginaw reverse lever is mounted in the side cover.
The M-22 close ratio transmission is easily identified INTERNALLY from the M-20 and the M-21 versions by the angle of the gear teeth. The M-22 was only produced in a close ratio version, so it will not appear on models with high rear axle ratios (3.55 or lower numerically) unless someone has changed it out. The “rock crusher” came in 70-73 years but was also in 1967 vettes. The M-22 differs from the 21 and 20 in the input shaft, cluster gear, first, second, third and reverse idler gear.
Can’t speak to the Saginaw Firebird 1967 vs. 1968 theory. I would imagine there was a mixture depending on engine type or more importantly axle ratio. Check your two digit axle code.
A: V-8s used Muncies,OHC-6 1 and 4 bbl used saginaws but a few 4bbl OHC had muncies ( assembly line goof ups), Easy way to tell apart is muncies are alum. and saginaws cast iron. Also muncies have the reverse lever in the tailshaft. No M-22 were installed in early Firebirds. First gear is 2.20 in a M-21 or 22
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Content last modified: January 20, 2014 at 10:19 pm
Q: Original Transmissions for a 1967
How can I find out what tranny is now in my 1967 Firebird since it has been replaced too, it started with an auto 2 speed but now has a 4 speed in the floor
A: The car could originally be had with:
3-Speed Warner (Manual)
3-Speed Saginaw (Manual)
4-Speed Muncie (close or wide ratio) (Manual)
4-Speed Saginaw (Manual)
3-Speed Turbo Hydra-Matic 400
2-Speed Powerglide (Automatic)
All tranmsissions have some type of model number information on them. Someone that has been around transmissions can tell you what kind of trans it is by just looking at the case. (You could also do this yourself. Pick up a couple of books on transmission rebuilding and compare the pictures.) The model numbers can be used to tell you what year if was manufactured, what gear ratios are used, etc, etc.
A: I hope I can clear up some misconceptions. The first generation Firebirds used a Dearborn (Ford!) HD 3-speed transmission when the floor shift was ordered or behind the 400. All pontiacs ordered with the Heavy Duty 3-speed got this tranny, too. This is basically a Ford top-loader and very strong. The Saginaw 4-speed was the weakest of the GM 4-speeds, Muncie the strongest then the Borg-Warner. The Saginaw 4-speed was an old 3-speed with an extra gear crammed in the case. The other 4-speeds moved the reverse gearset out to the tailshaft area, leaving 4 good sized gearsets in the main case. The Saginaw will survive serious abuse if the rear end ratio is high numerically or the car is light – I had a street rod with 4.11s and a 400 Chevy and didn’t break the Saginaw tranny despite many 4-gear smoke shows. I would keep the tranny you have until it breaks or starts making funny noises.
A: As for the question on the 3 and 4 speed trannys Pontiac used a Dearborn (Ford) tranny for GTO and Firebird V-8s and muncie for the V-8 with 4 speed. Saginaw is a good tranny and was even used in some Chevy big block applications . Pontiac chose to use it only behind the OHC-6s both 1 and 4bbl. I like this trans because there are so many different gear rations,3.50,3.11,2.85 and 2.54.
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Content last modified: January 20, 2014 at 10:21 pm
Q: Torque Converter Fluid Level
I am replacing torque converter and new one just says add fluid. How much? A quart? All it will hold before running out when vertical? Thanks
A: A torque converter will generally hold 4 quarts of fluid, I put 3 in and slip it into the trans.
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Content last modified: January 20, 2014 at 10:22 pm
Q: Turbo 400 Crossmember Position
Help! What direction does the turbo 400 crossmember mount? Does the bracket face forward or rearward?
A: The bend points to the rear.
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Content last modified: January 20, 2014 at 10:23 pm
Q: Electrical Kickdown Switch on a 1967 400
This car is original, but the engine/trans have been out before, so who knows what small parts are missing.
The passing gear on the transmission has never worked. When cruising about 35 mph, if you floor it, it just slowly(relatively) accelerates. It seems pretty obvious that it is not downshifting. The trans is rebuilt and has no problems shifting normally otherwise.
I found an electrical switch on the back of the trans that I was told was the kick down switch. I followed the wiring harness bulkhead on the the firewall, and have absolutely no idea where it went from there. Does the gas pedal actuate a switch that tells the trans to downshift?
Any thoughts/answers would be greatly appreciated.
A: Yes, the Turbo 400 has an electrical kickdown switch. I’m not sure where it is supposed to be located on a 1967 bird, but it will either be at the carb throttle (rare) or under the gas pedal. It should be set up so the switch activates at around 3/4 throttle or so.
Here is text from a reply by Jim Hand on the classicalpontiac web page (www.classicalpontiac.com) which explains kickdown/modulator funciton on TH400.
Folks, Here is some additional information on the Detent circuits (kickdown switch), and modulator function on a T 400.
The vacuum modulator is the prime controller of shift points when vacuum is available for a signal. However, as there is not adequate vacuum available at full throttle, regardless of what gear is being used, the modulator has no control over full throttle shifts.
Here is a summary of operation: The detent system (kickdown system or passing gear) on a T-400 has several functions. In addition to activating the kickdown gear (may be 3 to 2, 3 to 1 or 2 to 1), it also overrides the vacuum modulator circuit. Since most engines at wide open throttle (WOT) under load have little or no vacuum, the modulator has no reference point, and adjusting it will make no difference in shift quality or shift rpm under WOT load. The detent system replaces the modulator as controller of shift points at WOT, and it must be operating correctly before attempting to adjust the governor for higher rpm automatic shifts. The detent system also modifies accumulator pressure to increase oil pressure to the clutches for increased durability, so it is vital that it be functional in all cases.
All this means that if the kickdown switch is incorrectly adjusted to function at part throttle, the transmission will act as if the throttle is wide open in respect to the next gear change whenever the switch is activated. As quickly as the detent switch is off (by letting off on the throttle), the shift pattern will return to control of the modulator, because there will then be adequate vacuum for the modulator to function. It also means that if a T-400 is run without a correctly operating detent system, the clutches will suffer accelerated wear because the oil pressure is less at full throttle shifts. Additionally, the WOT shift rpm points will be lower without a correctly operating detent, or kickdown system. The detent switch should be adjusted towards the full throttle end of the accelerator pedal range.
A: Yes, the 1967 Firebirds with the Turbo 400 transmissions use a switch activated passing gear, (kickdown). The switch is a plunger style unit which is mounted to the intake manifold near the left rear of the carb. The bracket is secured to the manifold via the left rear carb bolt which holds the carb on the intake manifold. The switch is then secured to the bracket via it’s threaded neck, through a large hole in the bracket. The switch gets activated by an extension bracket which attaches the pedal linkage to the carb. There are two wires connected to the switch, one is black, the other is black with a green stripe.
The GM part number for the switch is #9785545 (same…. 65-66 P/8 M-40, 1967, 1968, and 1969 F/8 M-40).
I believe Classic Industries sells a reproduction of the extension bracket which mounts to the carb.
I haven’t seen anyone with a reproduction of the bracket which mounts the switch to the intake manifold. However, I went through many a junk yard looking for this switch before finding a guy who located an NOS switch for me. I “may” have a manifold bracket laying in my junk parts bin, I’ll check when I get home. If I have one, it is yours.
Let me know if you need pictures of this setup. You WON’T find them in ANY Pontiac, Firebird, or GM service manual, and there is no reference in any Firebird wiring diagrams that I have run across. I’ll be happy to take a few pictures and digitize them for you.
A: See also Engine F.A.Q. – Carburetor for more Kickdown Switch Information.
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Content last modified: January 20, 2014 at 10:26 pm
Q: TV Cable Purpose
I am installing a thm 350 in place of my manual trans. how important, and what does th tv cable do?
A: You can run without it, but you won’t be happy. The TV cable is what tells your trans to downshift when you stomp it (i.e. passing). A lot of people call it passing gear, but it’s just a downshift. Also, if you run without it, you will need to plug it’s hole or you will leak trans fluid. My cable was broken when I got the car, but the casing was still there and I could drive it with no problems until I could get one and had time to install it.
A: The TV cable also controls how hard the tranny shifts
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Content last modified: January 20, 2014 at 10:27 pm
Q: Rear Seal
I thought that I would change the rear tranny seal. Is it really as easy as it looks? Pry out the old one, tap it the new one…….
A: The rear seal on the tranny is as easy as it looks, pull and tap in a new one. I use weather-strip adhesive on the seals. You will loose some tranny fluid when ya pull the driveline so have a pan under the shaft when you pull it so you can expect about a quart to come out.
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Content last modified: January 20, 2014 at 10:29 pm
Reference:
- 1968 Pontiac Service Manual Section 7E
- 1968 Pontiac Service Manual Section 7F
- 1968 Warranty & Flat Rate Manual Section N
Content last modified: September 15, 2023 at 11:15 am