Greetings to you all. The Firebird I purchased needs some transmission work. It does leak some tranny fluid. It was stored and not driven for over 3 years.

I bought it as is. I was really unable to drive it prior to purchasing it and the family of the estate said they had it up to about 30mph and it maxed out. ( I think maybe it was slipping) I have not personally tried this because my house is a long ways up a hill and I am not about to get stranded. I drove it on and off a flatbed trailer and it seems to shift into forward and reverse just fine. They thought driving at very slow speed would be ok to get to a repair shop. Seller was not able to offer much information other than they said you just have to assume it needs rebuilt or replaced which I full expected prior to purchasing.

This brings me to the question of "what should I do"

I know the 2 speed is original, but just seems like a rather odd gear system. A transmission shop told me on the phone to throw it away and that the 2 speed is crap. Said to put a modern transmission with an overdrive and minor modifications would have to be made. So that is one option but probably spendy & I would do it myself if it is feasable.

I have also read from other owners that they have swapped out for a th350 which is a direct fit and you get a new shift linkage inside with an extra indenture. Sounds logical as a second option.

Then there is the 3rd option of just pulling the tranny and getting it rebuilt. Perhaps it is not real serious. I am thinking that it works fine full of transmission fluid. When it runs low it begins to slip. I think maybe a bad seal or something. I do not really understand auto transmission alot but have redone several manual transmission install and clutches. Leaking is only my theory. I think that because the family says it never had a problem before storgage. The car was not moved for 3 years and then they decided to sell it to me.

So I would appreciate others opinions and input on my tranny options.

Anyone else had these problems?

Is the 2 speed tranny really a pile?

Does changing it over effect the value because it is not original anymore?

If you did upgrade would you go with totally new type 4 speed tranny or just do a straight swap for a th350?

Lastly, is the tranny worth rebuilding and what should it cost me? I have never pulled an automatic transmission but would definetly do it to save every dollar I am capable of.

Thanks guys!

Rick
Gig Harbor, WA

When my 2 speed died I decided to replace it with a 4 speed automatic with overdrive (200-4R). The transmission was profesionally built by a shop that specializes in 4 speed automatics. I ended up going with this tranny:

http://www.2004r.com/trans/level2.shtml

I've been very happy with it although it was expensive. Here is a thread on my conversion and costs associated with it:

/forums/ultimatebb.php?ubb=get_topic;f=23;t=002126#000000

If money is an issue than I would probably try to find a BOP TH350 or TH400 which are plentiful and cheap.

G.J.
68 350 Coupe

I wouldn't go as far as to say the 2 speed is a pile. They can be built to be very strong. It's only flaw is it has 2 gears.

Before deciding on installing an overdrive, check you rear end gear ratio. It's probably a 2.54 or 2.76. If that's the case, you don't need an overdrive. A TH350 would be good enough.

The ST300 is a pretty tough tranny. I would top up the fluids, get rid of the old gas, put in some fresh stuff and go for a drive. See how the tranny shifts and if all is well then pull it and replace the front and rear seals, pan gasket and filter, put it back in and drive it. It will be a cheap fix you can do yourself to get you on the road while you save some cash to upgrade to either a turbo 350 or 200-r4. Hate to see you through a pile of money at the trans to find out the motor is toast.

Gerry

I appreciate all the feedback so far. DId not know my tranny was a st300. I have the 350 2 barrel. Is it necessary to pull the tranny to replace the seals?

it is necessary to pull the trans to replace the front seal. Is it leaking from the pan, the tailshaft seal, or the bellhousing? A section of clean newspaper set underneath may help.

I will study it. I put cardboard under it tonight. I am not real sure where it is coming from. Hopefully pulling the tranny out is really easy. Tight under the car. Hopefully i get adequate clearance when I drive up on the ramps.

T-56. It's the best replacement for an automatic.

I do like the way you think Q! (T-56!)

68FirebirdWaState... IF... I were going to do a swap, I'd weigh the cost, time and effort... and would end up with a TH350 as it should be the most direct swap for your application if you have the 2 speed.

Although... I do have an ST300 sitting here you could have for Free if you need it. I won't be using it, and if it comes to that.. you could give it a shot, and it wouldn't cost you anything but time and about a half hour drive each way!

Just let me know, and I may be able to help you trac down a TH350 if you decide to go that route? I have lots of Firebird and GTO friends all over the area here!

Welcome to the list!

Brett - 67 Drop Top 455!
brettnheather@hotmail.com (feel free to contact me directly)

I would go with a Turbo 350, it's pretty much a straight forward swap. Only issue would be the shifter, there is a conversion kit available to make it compatable with the 350-400 trannies. You can use your old driveshaft & crossmember with the T-350. Put a shift kit in it to firm up the shifts and it will hold up to anything that 350 2 BBL can throw at it!

Steve

I finally swapped a TH350 in place of my ST-300. I've only driven it with the new tranny a few times before the weather got lousy. It's amazing how much of a difference the lower first gear makes. Also, with three gears the engine seems to spend more time in the sweet spot of the power band.

There was nothing wrong with my ST-300, but I hated it. Wind it up to 70MPH in first and wait for the shift.

I don't think you're going to enjoy the project on ramps though. Put all four corners up on jackstands and use your floor jack to lower the transmission.

Auto Trans scissors-jack costs about $40. It is definitely worth it.

My ST300 would slip freely when I didn't keep the fluid at a reasonable level. I'd think it was failing then remember to fill the fluid and it would work fine again. It still shifted softly (they don't call them 'slushglide' for nothing) but 190,000 miles on the original clutch pack will do that.

The ST300/'Glide became the transmission of choice for drag racers in part because it is pretty stout. At very high horsepower levels the Al case can crack but the internals are pretty bulletproof for the majority of street applications.

I second the 'fill it and try it out' approach. My car had been sitting for about 2 years when all the tranny fluid dropped out - the seals dry up when they're not used. I haven't re-filled and tried it out yet but am expecting it to still be working.

I would not consider transmission removal from ramps. Use good quality jackstands at the corners.

Thank you all again. I am hoping to try it out next week when I get back and see what the mystery transmission does. Seems odd with about 61k original miles that it would be wore out. I am sure sitting for 20 years and off the road for 3 has dried everything out causing it to leak. I am doing all new gaskets on the engine now because they have shrunk and dried. Have seen a few drips on the water pump gasket as well as the thermostat. Carb needs to be rebuilt gaskets leak on that to. I might bite the bullet and just pull and store the 2 barrel manifold and go for the 4 barrel. For the little extra cost I think I will be happier with the higher HP. Cheers!