Exhaust Hitting Front Driveshaft

[MIPS]

Winter swooped in two days ago and immediately I discovered a new noise under the car when I switched into 4WD. The exhaust is striking the balancing weight on the front propeller shaft. It wasn't like that back in the fall and I don't recall hitting anything that could of bent the exhaust. I checked the hangars and didn't find anything skewed. The manifold flange is also still solid and I can't wiggle the exhaust so I can't tell what has shifted for me lose that half inch of clearance.
The only other weird thing I found underneath was my driver's strut rod bushing had come apart. The shop must of backed the nut off when they were either replacing the control arms or doing the alignment and forgot about it, but I don't see how a completely loose strut rod would cause anything to sag and flex the exhaust out of position.

[djm3452004]

Assuming the front propshaft is in the correct orientation, w/wide-diameter, slip-yoke section of propshaft at the rear?  (Image from '82 service manual attached...)

Winter swooped in two days ago and immediately I discovered a new noise under the car when I switched into 4WD. The exhaust is striking the balancing weight on the front propeller shaft. It wasn't like that back in the fall and I don't recall hitting anything that could of bent the exhaust. I checked the hangars and didn't find anything skewed. The manifold flange is also still solid and I can't wiggle the exhaust so I can't tell what has shifted for me lose that half inch of clearance.
The only other weird thing I found underneath was my driver's strut rod bushing had come apart. The shop must of backed the nut off when they were either replacing the control arms or doing the alignment and forgot about it, but I don't see how a completely loose strut rod would cause anything to sag and flex the exhaust out of position.

[AMC of Houston]

Motor mount shifted/squashed/dissolved?  Loose motor mount bracket?

[MIPS]

Assuming the front propshaft is in the correct orientation, w/wide-diameter, slip-yoke section of propshaft at the rear?

Yes. It was out early last year for U-joint replacement and it was fully inspected to make sure it wasn't bent or installed backwards. It was inspected again in October to make sure the SelectDrive was still working for the Winter, having not really been used for months.

Motor mount shifted/squashed/dissolved?  Loose motor mount bracket?

Got an easy way to check that? When the engine was pulled last year for the rebuild I asked if they wanted to take the chance to install new mounts and was told there was no need because they seemed fine.

[AMC of Houston]

Nope.  Seems to be no data in the manuals as to exactly where an engine should be sitting if everything is fine.   Might have to blame the problem on Gremlins!

[djm3452004]

Though they're a pain to get to, it may not be a bad idea to put a wrench on the (2) vertical 7/16-14 bolts with 5/8" hex heads that secure the front differential housing to the engine-mounted bracket, and then check the bracket-to-engine 3/8-16 bolts as well.  Just to make 100% sure that the front axle/differential isn't walking around at all.  If you're looking for something loose with the car sitting on its front suspension, a loose part may be partially loaded and not entirely obvious that it's loose.

Don't know, just thinking out loud...

David

Nope.  Seems to be no data in the manuals as to exactly where an engine should be sitting if everything is fine.   Might have to blame the problem on Gremlins!

[MIPS]

I can give it a try once my jack thaws out. The last weekend was hitting -30c and it was absolutely brutal on anything I left outside (eagle started fine though.  )

[MIPS]

FYI, the reason the exhaust was now hitting the shaft was the transmission was loose on the mount and shifted to the right.
Between adjusting the exhaust a little and replacing the mount, it's all good again.