Drive Train Problem

I've got a 48 2a with a t90 that's developed a problem somewhere in the drive train. When I take off in reverse or let off the accelerator there is a pop that I can here and feel. Trans shifts fine and there aren't any other strange noises. I was wondering if anyone might know where to start looking before I pulled the trans and transfer case out. Thanks

 

Check your U-joints.

 

Do you still have the parking brake on the back of the transfer case? If its there, the shoes could be catching when the drum spins the opposite direction.
-Donny

 

Look for rust or metal shavings around the u-joint caps.
Check the bolts to make sure they are tight.
Check the rear axle nuts to make sure they are tight.
Lots of "could be" areas to check.
Removing trans/transfer case would be the last option if you can't find any other problem(s).

 

If all else checks out, remove the dust caps on the rear hubs and check for loose axle nuts (tapered axles only). Edit- jpflat2a already covered that.

Another thing to check is the spring eye bushings on the fixed end of the rear springs.

 

maybe a mount is broken or severly worn out???

 

x2. Try going from forward to reverse and back in the driveway, listen for a clunk when the driveshaft loading shifts.

 

Check the bull gear on the back of the transmission,in the transfer case. Mine got worn and had slop on the splines. Put a different one on and all was well again.

 

Slack in driveshaft splines

 

Besides all of the above, take a look at the trans crossmember bolts and the ubolts on your leaf springs too. I have found both loose enough to make noise when given sudden loads.

 

Yes thats very common. If the nut is loose you can almost guarantee it.