Drivetrain vibration, wrong slip yoke?

[Wall]

OK here's alittle background, not too long ago I had a noise develop in the rear end so I tore into it one weekend and found the front pinion bearing had came apart so I replaced all the bearings and races in the rear end and the noise was gone but I have a intermittent vibration now. After looking around for the problem it looks like slip yoke is sticking out of the transmission more now than it was so I believe that's where my vibration is coming from. I have a richmond 4-speed and from what I've seen it uses a TH400 32-spline slip yoke so where can I get a longer slip yoke?

[Jim H]

How is it the driveshaft became shorter? Replacing the pinion bearings will in no way will effect the yoke changing location on the output shaft. Check your ujoints and also the bushing in the tail housing, these can give you a vibration. Pull the drive shaft and move the joints in all driections. Make sure there is no movement in the caps and also make sure it moves freely without any tight spots.

[andrewb70]

If the slip yoke is sticking too far out of the trans than you need a longer driveshaft. Got a picture?

Andrew

[KeislerRich]

andrewb70 is correct. If the yoke does not have enough engagement on the output shaft you will indeed incurr a vibration. What is the distance from the machined surface of tailhousing to the center of the FRONT u-joint??? A picture will help....

Richard
Tech Support
Keisler Engineering

[Wall]

I will try to get a measurement in the next few days.


The reason for the "shorter driveshaft": I believe whoever installed the transmission in this car initially had this problem and thier fix was to loosen the pinion yoke which in turn pushed the driveshaft forward and took care of the vibration but because of the slack in the pinion yoke it eventually caused the pinion bearing to fail.

[keislerNick]

Typically on all cars except mopars if you are using a TKO trans you will measure from the macined surface on the trans to the center of with the u-joint cap sits in the differential. Then when its made they should only cut 3 inches off that measurement add a yoke and your perfect.

[Wall]

If the slip yoke is sticking too far out of the trans than you need a longer driveshaft. Got a picture?

Andrew

Well I got to work on the car the other day and the yoke was only sticking out of the trans 7/8 of an in so the driveshaft length is ok, from what I've seen 3/4 -1in is acceptable. So that makes me think the yoke is too short. I took the slip yoke out and measured from the end of the yoke shaft to the center of the u-joint holes and it is 5.5in (the yoke shaft alone is 3-5/16in).

[andrewb70]

The length sounds fine. Are you sure your rear bushing is not messed up? How much play is in the yoke when its on the output shaft?

Andrew

[Wall]

I'll probably have to post pics tomorrow to help explain this but there are 2 different shiny marks on the shaft of the yoke where the seal was rubbing meaning that it was riding further in the trans until I tightend the pinion yoke up(after replacing the pinion bearings)and it pulled the driveshaft towards the rearend and out of the trans more, that's when the vibration started.

[Wall]

Here's a pic