Tranny hum

[ChuckR]

Hi. Just put a (good) used 4 spd in my '69. Replaced clutch, pilot bearing and throw out bearing. Put it all bk together (all mounts, exhaust mount etc all good) and car is transformed, snicks into gear, feels tight. However, I get a hum in first, second and third goes completely away in fourth. And the hum seems to go away w clutch in. My older tranny (w Porsche syncros) didn't do that, was quiet but was very worn out and wouldn't shift without grinding.

Is there something to check on the instal other than part interference, center bearing preload, so on? The shift rod seems awfully close to the shift arm/platform..

Thanks chuck

[c.d.iesel]

damaged the pilot bearing on installation ?

noise inside used gearbox ?

stethiscope listen to it while it

runs on jack stands?

defective throwout bearing ?

what type oil in the box ?

[ChuckR]

thanks for response CD.

I used Redline MTL.

I thought of the pilot bearing and/or the throw out bearing (read warnings about not hanging the tranny on the pilot so was very careful to support during entire process), but the hum going away in 4th suggested something other than those bearings...

i'll run it on stands and listen to tranny.

Chuck

[Guest Anonymous]

No hum in 4th gear? 4th gear is the only straight thru gear with no reduction or step up ratio. So I would look at the bearing inside the trans that supports the shaft that holds the gear that transfers torque to the 1-3rd gears. It is probably the noise culprit. Humming Noise may be a long way from a failure so drive on.

Have fun

[ChuckR]

thanks for post. update: the shifter rod separated from the tranny last night! not exactly sure what happened - as it was installed correctly with the pins and joint cover, i am waiting to tow the car to see what happened...sheese.

[ChuckR]

update. had my mechanic friend drive my car. sure enough, the 'hum' = bad bearings. arrggg.