An existing flaw in the casting and metal fatigue may simply be the answer, but it's human nature to look for the "tipping point" . Make sure they shore the engine adequately. As soon as the transmission mount is removed, the drivetrain will want to twist in its mounts and they weren't designed for that. Hopefully, you've found a good shop - your jeep needs a little luck

 

So very true!

 

Have now inspected transmission case and mounts. All mounts have multiple cracks. Can't see much detail on pass side motor mount. Driver's side motor mount (see picture) has lots of cracks and appears delaminated at the bottom. No significant engine movement obvious. Transmission mount cracked in many placed but not separated. I'm enclosing pictures of of the crack on transmission case. I've also added photo of a rubbing area on the top of the case. The actual measured distance to the rectangular plate above is slightly more than 3/8"

 

OUCH - gave me a sinking feeling just looking at them - clearly, the transmission was allowed to move and replacing all mounts and checking the learance around the new transmission is your next obvious move

 

Tried to get OEM mounts. Talked to the local (San Jose, CA) Chrysler Jeep dealers. They pointed out the OEM part was obsolete (surprise) and my only option was aftermarket. They also pointed out that "no dealer" could afford to stock any inventory item that didn't move in less than 2 weeks. I opted for rubber for both the trans and engine mounts.

 

That transmission needs replacing, it possibly got a hard hit, or was incorrectly mounted sometime in the past.

I obtained a couple of used '96 trans for mine from a private seller for $125 each, a day to take it out and another to put it back in, working on my own, on the concrete

A transmission jack is really helpful, I used regular jacks, which wernt much fun for the TX case

A BIG tip...replace the front oil seal behind the torque convertor ($20). I didnt on a whim, so I got to repeat the whole job straight away.

another tip, undo the T12 bolts at the top of the trans FIRST...you probably need the correct T12 female socket

I was much quicker 2nd time around lol

 

“That transmission needs replacing, it possibly got a hard hit, or was incorrectly mounted sometime in the past.”

I agree, but that’s what’s so confusing! About 6 years ago, I decided to go rock climbing. I bought a set of Skid Row armor plates for the engine, trans and fuel tank and had them professionally installed at 4WD. Last rock climbing event was two years ago. No recollection of hitting anything and no transmission problems since I bought it till this crisis! BUT, looking at the top of the transmission picture, one can see bare metal rubbing AND at about a 45 degree angle! Is this the evidence of what happened to cause the case crack? There are significant gaps between the hearty skid plates and the trans…

 

On the issue of replacing the trans - had this happened at home I would have taken on the replacement with a trans jack and on my back on the garage floor!

But watching the trans guy work this with a professional lift, the right tools, the support system for the engine - sure easy to see the level of pain it would be for me to take it on. Also very glad the trans guy lets me watch inspect and question!

 

I have a couple of 6" bolts with the heads cutoff and slots that thread into the engine block in place of the bell housing bolts. Makes it much easier to get things lined up and slide in place. Is your cross member still straight?

 

Have finally gotten the rebuilt transmission installed and the mounts removed and replaced. I'm enclosing a picture of the driver's side motor mount. Clearly broken letting engine swing +/- 1 inch with trans mount as fulcrum. Just before the top of the swing permitted by the broken mount, the transmission top can hit the screws of the rectangular projection at the top of the tunnel. The passenger side mount is extensively cracked but not broken. Likewise, the trans mount was extensively cracked but not broken. My trans guy is convinced that this is the cause the cracked transmission.

 

I believe your trans mechanic is indeed correct - but this was an unfortunate way to find out that you needed moter mounts. I assume you had to find a salvaged trans and rebuild it. Given the demand for these units, my hat's off to your mechanic for getting you back on the road so quickly. What is the name of the shop and where is it located?

 

Indeed, we found a salvage transmission located in San Jose, using Car-Part.com. My transmission guy (El Camino Auto Transmissions) then did the trans rebuild and got a rebuilt torque converter from an unknown (to me) local rebuilder. Over these past few days I’ve been very impressed with this guy!

 

BTW, as the rebuilt trans was installed, everything lined up perfectly with new mounts in place, including transmission crossmember.

 

Good the hear ! Hopefully, your next post will be your refurbished transmission carrying you down a 4x4 trail!

 

I have the long bolts, but did not cut the heads of, just placed them through the bellhousing holes, and used them to help line up the trans with the threaded holes, then used them to pull the trans in, then took them out one by one when it was close enough to use the originals