It's supposed to have a certain degree of offset( 2* comes to mind). Also since neither the tail shaft or the pinion are perfectly in the center of the car you get some sideways misalignment as well. Keep the Greene moving around in the u joints. If they were dead on straight nothing would get lbricated.
He is talking about the phase of the u joints on the shaft itself not drive line angles. Yes they should be in phase but I have seen factory shafts that were as much as 30 degrees off. Go figure.
My shaft is like 30 off it just didn't look right. Can't believe it's not binding. This might be noise I thought was weel bearings. Having a new shaft made up for my set up. Thanks chief
the driveshaft was designed "out of phase" to eliminate vibration. Probably has something to do with the off set of the engine. This '69 ad actually mentions it. .
When I had mine rebuilt there was an older man (couple years older than me) who remembered there was "something weird" with Firebird driveshafts and said it should be rebuilt the same way.
I have an original shaft in my 68 that is in perfect phase. But have seen 2 original shafts that were out of phase. Makes you wonder which cars got the ones out of phase.
Wow good looking on the add... Here's the question... I now have a LS1 with a 4L60E trans and 12 bolt rear. I'm going to error on the side of caution and have a new shaft made with no offset As the rear end was already there and I had a vibration. Guess we will see. Thanks guys
Funny you guys are talking about this, I actually pulled my drive line off of my 68 Firebird 350 HO 4 speed Convert, 36000 original miles, (the factory u-joints installed) Monday to repair the rear u-joint. My drive shaft is out of phase? I've had this car for 27 years, and it was my friends Mom and Dads car since new, so I know the history of the car. I brought the drive shaft to my work to repair it and when the machinist saw it he said it was messed up, and that it should be in phase, and recommended that we cut it and line it up, also the yolk shaft, on the front of the drive shaft was worn down in the middle, he said it was due to the mis-phasing and could cause transmission problems, because the drive shaft was wobbling. And I do agree with him. Well I am going to a car show this weekend and needed to get this fixed ASAP, so I have a 69' Camaro with a 12 bolt 4 speed in her and we thought that might work for my Bird. So my son pulled the drive shaft off the 69 Camaro, and when I got home last night it had the same out of phasing as my Bird? So, does anyone really know for sure why this is?? And if so why only on certain cars? And can this cause the yolk shaft to get worn down? My friend had a used yolk and we are installing it on my original drive shaft right now, but should I cut mine and phase it, or leave it and worry about the tranny going bad??
A drive shaft that is “in phase†and has the correct operating angles at the drive end of the shaft does not create a torsional vibration.
Drive shafts that are NOT in phase will vibrate with the same twice per revolution vibration as a drive shaft with incorrect operating angles.
The easiest way to make sure your drive shaft is in its correct phase is to mark the tube and slip yoke every time you take it apart so you can put it back in its original orientation when you re-assemble it.Re-assembling a drive shaft out of phase is the #1 cause of torsional vibration that “all-of-a-sudden appears†in your application. If you suspect that your drive shaft is not in phase, take it to the closest Machine Service location for inspection.
Funny you guys are talking about this, I actually pulled my drive line off of my 68 Firebird 350 HO 4 speed Convert, 36000 original miles, (the factory u-joints installed) Monday to repair the rear u-joint. My drive shaft is out of phase? I've had this car for 27 years, and it was my friends Mom and Dads car since new, so I know the history of the car. I brought the drive shaft to my work to repair it and when the machinist saw it he said it was messed up, and that it should be in phase, and recommended that we cut it and line it up, also the yolk shaft, on the front of the drive shaft was worn down in the middle, he said it was due to the mis-phasing and could cause transmission problems, because the drive shaft was wobbling. And I do agree with him. Well I am going to a car show this weekend and needed to get this fixed ASAP, so I have a 69' Camaro with a 12 bolt 4 speed in her and we thought that might work for my Bird. So my son pulled the drive shaft off the 69 Camaro, and when I got home last night it had the same out of phasing as my Bird? So, does anyone really know for sure why this is?? And if so why only on certain cars? And can this cause the yolk shaft to get worn down? My friend had a used yolk and we are installing it on my original drive shaft right now, but should I cut mine and phase it, or leave it and worry about the tranny going bad??
They are made that way so just put new u joints in. No need to cut and re weld. I had mine balance checked. The Drive line guy know right away what I had when he saw the drive shaft. He did not say there was anything wrong. He tested the balance and it was fine.
I have been doing a lot of research on this subject and no one can really explain, or knows why on first gen Camaros and Firebirds why some of the drive shafts were out of phase, but everyone agrees that this is not the correct way for drive shafts to operate with out some type of wear or damage. On my Firebird, as I mentioned, the yolk is damaged, it has excessive wear in the center of it, kind of like an hour glass/coke bottle wear? Has anyone else had this issue?? I did replace the u-joints at lunch today, and they were fairly dry, but not totally shot where this would cause vibration issues. I also replaced the yolk that was wore. I'm curious to see if my transmissions rear bushing and seal are toast, and possibly rear tail housing, and also if there is very much lubrication in the tranny? I'll be installing the drive line back in the Bird tonight, and will check for "tightness" on the transmission shaft, seal, bushing and see if they need to be replaced. Also the yolk on my 69 Camaro with the out of phase shaft has the same wear on it's yolk?? Very interesting... Do all out of phase Drive shafts cause this problem?? Has anyone else seen this?? For the money, and ease of mind, I think when the car show is over I'll replace my drive shaft with an in phase one. Any comments are really appreciated. I'll let you all know how this turns out.
Last edited by joedirt216; 06/17/1506:43 PM. Reason: spelling
After a big fight getting the rear output shaft seal out, with a little help from my granddaughter, the output shaft bushing from what I could see looked fine, the output shaft had no play, and thank gosh, there was still fluid in the tranny. The old seal rubber was hard and cracked, and had seen it's better days, I opened up the filler plug and couldn't get any fluid on my pinky. I installed the new seal, driveshaft and added about 1/2 quart of gear lube. I took her for a ride and she felt good, no noise or vibration. I'm still not sure what I'll do when the show is over, we'll be going 300 miles one way, and 300 home. That ride should give me a good indication of the wear on the slip yolk, if any. Definitely bringing some tools and extra gear lube to check it along the way.
So tonight while working on the Bird, my son arrives in his 68' Camaro, 396 4 speed, a car I bought in 1980, and gave to him last year, the drive shaft on it is also "Out of Phase", so WT???? If I get time tomorrow I'm going to pull the drive line on the 68' Camaro and check it out. Cheers!!
From what I gather Fbody driveshafts were made out of phase on purpose to try to stop vibration. IHad always had a vib in the car for as long as I could remember. Back in the 80s the vib got so bad at around 120+ that the the u-joint broke and the driveshaft went flying out of the car(after causing all kind of damage). I had to replace the shaft with another from a wrecking yard. It had the same issue. I lived with it for years because it didn't show itself until 80+ mph. Last year I pulled the driveshaft out to get it balanced. The yoke was toast and so was the tail shaft bushing( if one is rough you can figure the other is as well). New yoke, u-joints, tail shaft bushing and a balance job and she runs smooth to at least 115 now( as fast as I've taken it yet).
I also have a vibration at about 60. I have a new yoke, new u- joints and have had it balanced twice. Better but still there. I'm thinking new shaft but after reading perhaps I should look at the tranny? Original 4 speed.??
For a manual transmission to cause a vibration it would literally have to be falling apart, bearings falling apart...etc. Would try and narrow down other common causes. Bent rim or axle flange, bad tires...etc
I agree with chief on Trans causing vib but if the part of the yoke that slides into the tail shaft is worn, grooved or otherwise torn up, you can bet the bushing inside needs replacing as well. You hear a lot of talk about driveline angles but if everything is bolted in correctly it shouldn't be an issue. There's lots of things that can cause a vib including bent axles, bad bearings, bent rims, bad tires, broken mounts. You can go two ways with it, start at one end and fix or replace till you get to the other end or start with the least expensive to the most. Sucks replacing stuff that's perfectly good but at least you end up with new parts on the car and good spares for in case.
Well I made the 600+ mile trip with no issues. I am going to pull the drive line some time this week and see if the new yolk has any wear, regardless, I still think the tranny is coming out so I can replace the tail shaft bushing. I'm still not sure what to do about the out of phase drive line yet. Everyone says to line it up, but if GM had a reason for doing this, will I be causing another problem?? I'm surprised a lot of you guys on here aren't looking under your Birds to see if the drive lines are in or out of phase?? It sure would be nice to see how many are out of phase. Should we start a poll?? This information could sure help out a lot of people.
OK, here's a pic of the yoke end and the bearing end, no where near in phase, It's the one I took off my 68 coupe. The rear was a Chebby 10 bolt from a 69 Camaro, I assume the driveshaft is from the Camaro as well. I THINK the BOP rears had larger u joints than the Chev rears but I'm not sure, could be the original 68 Firebird shaft but I'm thinking 69 Camaro.
You are correct, the driveline out of my 69 Camaro, had smaller u-joints than my 68 Bird, and it has a 12 bolt posi 4speed ,but all 3 drive lines were out of phase, my 68 Bird, the 69 Camaro, and my son's 68 Camaro, I still need to pull the drive line on the 68 Camaro, and see how the slip yolk on it looks. The show was in Coeur d'Alene Idaho, they do a classic car parade on Friday night and a car show on Saturday, it was pretty cool, about 1200 cars, the parade was rough on the old cars too slow moving, still was a great time though.
Does anyone know any guys that worked at GM on these cars? It would be interesting to find out why they did what they did on these F Body cars. I have never seen driveshafts phased this way out of any other GM vehicles such as A or X body car's or I missed something.
There has been a lot of discussion on "CRG" Camaro Research Group, on this out of phase drive line issue, no one really knows what the reason for the out of phase, and if it did work, then why did they discontinue to do it?? This is a very interesting subject, and it would be nice to know the facts. The Car d'Alene show is huge, lots of cars you just don't get to see in person, I'm not sure of the total amount but over a thousand cars I'm sure.
![[Linked Image from i601.photobucket.com]](http://i601.photobucket.com/albums/tt95/920-680-1902/firebird/Photo_2006_1_29_22_27_15_edited_edi.jpg)
