4th gear noise

[Brent B.]

I have a 62 340hp with posi-traction that makes a strange noise in 4th gear only. It sounds like the driveshaft is rattling. The noise is in 4th gear and only occurs when the engine is under a load. The following parts have been checked:
- replaced pilot bushing
- replaced bearings, seals and tailshaft bushing in the transmission
- replaced u-joints
- replaced transmission yoke on driveshaft
- all splines are straight and are not worn
You can't feel the noise in the shifter and it does not go away if you press on the clutch pedal. When the car is cold and in 4th gear the noise occurs with a slight engine load. Once the car warms up you have to put the engine under a heavy load in order to make the noise occur. Any help would be greatly appreciated.

[William C.]

Re: 4th gear noise

Have you checked the fit of the ball bearing in the plate at the rear of the main case? I had one that had a little slop between the outer race and the bearing retainer and it caused a similar situation.

[William C.]

Re: 4th gear noise

Have you checked the fit of the ball bearing in the plate at the rear of the main case? I had one that had a little slop between the outer race and the bearing retainer and it caused a similar situation.

[Rich Puleo]

Re: 4th gear noise

Hey Brent,
If you don't drive the car much & want to try an easy fix, this usually works if the mechanical problem isn't too serious. Drain the fluid as best you can, fill with new gear oil, synthetic 80-90 unless you're racing or have a fresh unit, & add a bottle of Kendall posi additive. The friction modifiers quiet up alot of noise. The trick here is just make sure you're masking an annoying noise, not a serious problem.
Good luck
Rich

[Rich Puleo]

Re: 4th gear noise

Hey Brent,
If you don't drive the car much & want to try an easy fix, this usually works if the mechanical problem isn't too serious. Drain the fluid as best you can, fill with new gear oil, synthetic 80-90 unless you're racing or have a fresh unit, & add a bottle of Kendall posi additive. The friction modifiers quiet up alot of noise. The trick here is just make sure you're masking an annoying noise, not a serious problem.
Good luck
Rich