TF 727 problem (maybe)

I have an 81 SJ with the 360/torqueflite 727/NP208. I think the 727 has a problem, but at this point I'm not entirely sure if it's the tranny or the transfer case that has the problem. Whenever I put a lot of torque through to the wheels, I hear a horrible grinding noise. It sounds like it's coming from the transfer case, but I'm pretty sure it's the tranny. It usually does it on hillclimbs in low range, but today it did it under hard acceleration in 2wd.

If it's the tranny, I have no idea what the problem is or what to do to fix it. I've heard the 727 isn't the greatest of transmissions, but I'm willing to live with it for now.

The only other thing I can think of is that the motor or tranny mounts are shot and the whole drivetrain is twisting so much under the torque that the linkages are shifting my transfercase partially out of engagement.

Any thoughts?

Could it be the transfer case chain slipping?

Are you certain of the transfer case number? I thought by '81 Jeep had standardized on the 228 in the SJs. Do you have QuadraTrac, or do you have a 2WD high range?

Are you certain of the transfer case number? I thought by '81 Jeep had standardized on the 228 in the SJs. Do you have QuadraTrac, or do you have a 2WD high range?

Click to expand...

OK....the "REAL" QuadraTrak stopped being used in 1979 (though for a bit Jeep called the NP219 QTalso). In 80 Jeep went to the NP208 and the NP219. In 82 they switched to the NP228. In 83 They switched to the NP229 or something like that. The NP208 was available until in 87 I believe in the J trucks.

If it is the chain it will slip (and grind) no matter what gear you are in because in all these cases the chain controls the rear output ALWAYS.

To me...it screams chain...but check out www.ifsja.org for your full size Jeep needs. =)