davek9

How do you all determine if the Trans mounts are bad, will the trans hit the cross member, if not than what's a good measurement for a manual trans to cross member spacing, and is it different for an Automatic?

Thank you,

Dave K

dr bob

Dave --

There are a few posts about mounts that show a collapsed mount next to a good one. Probably the easiest "test" is visual, with a finger to put in that top gap. If you can easily pass a finger into the top gap they are OK. When they collapse that gap gets small. Some are reporting that the gearbox sits on the crossmember; in my case, that bottom gap to crossmember with the collapsed mounts was never so tight that there was contact, so I'm not sure there's some "if it's tighter than N, mounts have failed". I can easily get my thumb in the gap in the new mount itself; Not as objective as possible, but perhaps a good pass/fail guidance.

davek9

As always Dr b, thank you for the prompt response!

Understood thumb and finger size vary per user
I'm looking at a '91 GT, that a long time friend asked me to check, I have at least an inch of Cross member to Trans spacing and after cleaning I can feel a decent amount of "gap" in the mount, the car runs great at Hi-way speed w/o any noticeable vibrations too.

Dave

SeanR

These were off a 5-speed, typically the same on an auto.

z driver 88t

That's a good photo Sean. Mine were not that far gone - kind of surprising considering they were probably original. My left mount had definitely collapsed further than the right. My theory is that is passes so close to the exhaust pipe that the heat softens the rubber and allows it to degrade faster. My passenger side mount actually looked pretty good. With that said, I can definitely feel a difference in the smoothness of the drivetrain with the new mounts in place. Hopefully this set will last another 35 years and I won't ever touch them again.

davek9

Yes, thank you for the Pic Sean, looks like 12mm diff ?

Dave

JayPoorJay

I don't know if it's a model year thing or what,,, mine is an 86,,, but for the life of me (and I wasn't just messing around) I could not get the 78 mounts to fit. The smaller one (on the 86) was a complete no go - where the mount bolts to the crossmember was in a completely different place....

The larger one came up against the under body of the car which in turn offered no space for fitting. I might have been able to knock the body section out of the way, bending/denting it (which I did a little) and still, awkward... I believe had I gotten things together, with movement, the body of the mount its self would have been pressed up against the body section (the underside of the rear seat on the driver's side) and would have sent vibrations thru the entire car body, I'm sure.

I removed both axles
Lowered subframe
And still

Ended up just re-placing old mounts,,,, for now. I need a money tree for the newer...

Maybe a better man,,, but not this one! Shoot

Did get XJS near completely reupholstered tho!!! That's a good thing.

Thank you all for your help, suggestions, guidance and attention. Piece...