[pknopp]

Originally Posted by Doug

I think 1958 was the first year for a Pontiac posi. The 57 and 58 both used 29 spline axles. 59 thru 64 used 31 splines. I'm pretty sure these later carrier assemblies will fit a 57 housing
and you can use the 57 axles if you change out the side gears, which (I think, maybe) are now being produced.

You very well could be right about the first year offered being 1958, but it will fit in the 57 rear unlike the 56 and back.

[694.1]

Looked again at this car and the vibration is definitely from the engine & this appears to be the only issue. Great car but also big money (for this guy).

[Engine-Ear]

Dave (694.1), call Dunham's in West Allis.

And buy this car already, will ya? ...Ya been hemming and hawing about this thing for a year!

[694.1]

Update: Something interesting is happening. Wish me luck!

[Tommo99]

I just rebuilt mine with a kit from Dave at autotran he has a very basic web page but has an awesome full rebuild kit for I think about $450 and he has all the schematics, he was very helpful, I had to make a puller to pull the clutch pack apart, I wouldn't recommend doing it yourself unless your quite mechanically minded as it's got a lot of parts and you need to make a few drifts up for pressing out some of the bronze bushes, if u have the time and patience then have a crack at it.

[gavin]

Suggest google rolls royce gearbox rebuild as they used Hydros for many years (early fifties to maybe early seventies ) and you might get a good idea of whats involved.I dont know how much they evolved but they are still the same basic gearbox.

[Bill Hanlon]

I think that the last year of RR built Hydra-Matics was 1966. Some had a disk-type parking brake on a shaft sticking out the right side of the tranny near the rear. Otherwise they are very similar to GM transmissions. Good info on RR Hydra-Matics can be found here:
http://www.kda132.com/pdfs/technical...Suspension.pdf

[pontiacpark]

I bought a rebuild kit for my 347 and hydamatic in my 57 gmc on my last trip to your great country. A buddy over here and he posts on here rebuilt his own hydamatic last year. I had trouble with my tranny a few years back and we did get it fixed but it was a slow process checking everything and adjusting. Many thanks to steve p with the great sdvice he gsve me on this site. However later on I removed the motor and tranny and a few months back i installed a 400 motor and Trans out of a 68 Catalina. I used the aftermarket crossmember so you can buy for a early chev truck. For 3 k it is now running and running well. I had a buddy help me and it took a week of after work days to finish. Now it Goes great . I put the original 265 thousand miles motor and tranny from the gmc under my bench so I may rebuild it when I can afford. If not I will just enjoy it as it is. I haven't noticed any problems with incomparable ratios. I not long did a 800 mole shakedown run over some pretty windy roads with no problems. Haha. Tell you what though. The gmc certainly gets up ND goes a lot better than it ever did and a lot quicker than the designers ever visioned.

[pontiacpark]

Did you have any parts left over tommo

[694.1]

Pontiacpark, we want pictures!

[pontiacpark]

Ok. Give E some time and I will climb under and take some photos.. my 57 gmc is on this site if you search my posts.

[pontiacpark]

Took pics. Having trouble loading. I'm happy to send to a member and they can upload. ?