I have this problem that i can't figured out.. It's a kinda grinding , high pitch sound that i can feel in the shifter stick.. Mostly on the 5th gear but in 4th too.. Over 60mph, the sound dissapear..

Anyone has an idea?

Cheers,
Marc/

 

Sounds are the worst thing in the world to diagnose. But, it is always a good idea to verify that the 5th gear fix has been made to your transmission. If the nut starts to back down, 5th will sort of partially engage and will howl until you get so much load on it that it pulls into the meshing gear. Sometimes when the nut is starting to work loose and you are in 4th the 5th gear shift fork continues to rub on 5th and will also make a bit of noise.

Other than that, the main bearing in the rear of the transmission housing starts to get excessive wear and will make a bit of a growl. That noise is generally only heard in direct or overdrive, as the loading on the main shaft when in lower gears keeps it quiet.

Given the age of the truck, I would use a moly additive in the transmission and slightly overfill it to get more lube up and on the rear mainshaft carrier bearing. Other than you will have to be a bit slower in shifting, because the moly lubes the synco brakes and makes them less efficient, it will not hurt a thing. However, it may just quiet the transmission if it is a bearing issue and save you the cost of a repair.

 

RCW,

Thanks for the advices, but it's kinda hard to explain a 'noise'.. It's always easier when you ear it.. The 'noise' i have is not when i shift gears, but when im in gear. It sounds like an high pitch vibration in the stick.. Over 60mph, the sound dissapear and below 40mph, nothing.. Fork shift might be a good guess.. The tranny has never been open, and the last owner didn't make much maintenance so i doubt that the 5th gear has been fixed.

Cheers,
Marc/

 

Call the experts at Standard Transmission 800-783-8726 and explain the problem.
Most times just the secretary who answers the phone will tell you what's wrong.