Transmission mount removal issues

I noticed while re-installing my son's transmission and the support beam under it, the beam has a big hole for something (like maybe some kind of insulator) that wasn't there in my case and maybe not yours.

The front of that support beam has rubber isolators between the beam and car body where the bolts go through to mount the beam. The very rear of that beam is bolted into the body metal to metal.

As I tightened the front beam bolts down, the transmission case was resting on the metal beam - metal-to-metal.

I loosened up the front beam bolts and installed a 4"X5" piece of rubber matting about 3/16" thick into that area and tightened up the bolts hoping this will help dampen any vibrations.

Note:
Further researching this issue, I found parts breakdown listing at the link below.

It looks like there are vibration dampers but why would one near the center of the cross beam be on the "underside" of the beam?

See lower drawing of the two on the webpage linked below for the manual transmission parts.


A partial snapshot from the website page is attached below.
Yes my brace had that same hole, I believe that is where my mechanic installed a rubber mount. I will check next time I'm under the car. Whatever he did it fixed the problem entirely.
 
After checking the L/h transmission mount and finding it to be ok I still had a vibration, it turned out I had some contact between the gearbox and the under engine support brace, this has now been rectified
This could totally be a placebo effect or a result of my oversensitivity to mechanical vibrations and noises, but I feel like I'm experiencing this as well. I'm definitely following this conversation with a decent level of interest now.
 
This could totally be a placebo effect or a result of my oversensitivity to mechanical vibrations and noises, but I feel like I'm experiencing this as well. I'm definitely following this conversation with a decent level of interest now.
I recommend replacing all engine mounts, in my case it went from a dull loose type sound, and then after replacing all mounts got worse, solved by diff brace rubber.
 
I recommend replacing all engine mounts, in my case it went from a dull loose type sound, and then after replacing all mounts got worse, solved by diff brace rubber.
Thanks headofjar - All the engine mounts have recently been replaced by someone before my son bought the car along with the timing belt (I've been informed):cautious:.
And now since doing the transmission R/R, 3 out of the 4 mounts and bolts have been re-accomplished as well.

---Other

When I went underneath to start the transmission removal (to replace the clutch), I found the person who did the motor mounts left one transmission mount bolt out, a motor mount bracket bolt out and its transmission casing entry hole chipped off and the other motor mount bracket bolt loose (felt like it was stripped) - (see attached photo).
Not a happy moment for me as I've already bought a ton of parts to replace. 🤬

Luckily, I swapped out a couple bolts and dug one out of my bolt bucket that even though it was a bit too long, I washer-ed it up and the threads finally bit and held.🥳

On the chipped-out one I used some extra loctite on the bolt threads and the mount bracket has some surface area to spread the bolt/bracket load so now I feel more ok with that one.
 

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I recommend replacing all engine mounts, in my case it went from a dull loose type sound, and then after replacing all mounts got worse, solved by diff brace rubber.
I have newish (~6 month old) OEM front and rear mounts installed. The passenger side mount is in good condition and has an AWR Polyurethane insert. The trans mount looks fine but I have an aftermarket replacement for it that I've been putting off installing. I had an AWR trans mount insert previously and it made the car horrible to daily drive (extremely loud, lots of vibration, still lots of lurch/bucking).

I wholly agree with your statement that messing with mounts is a rabbit hole. I've spent too much time, effort, and money trying to make the car drive better without bucking and horrible cabin vibrations, and frankly it has mostly been a waste of my resources.
 
I have newish (~6 month old) OEM front and rear mounts installed. The passenger side mount is in good condition and has an AWR Polyurethane insert. The trans mount looks fine but I have an aftermarket replacement for it that I've been putting off installing. I had an AWR trans mount insert previously and it made the car horrible to daily drive (extremely loud, lots of vibration, still lots of lurch/bucking).

I wholly agree with your statement that messing with mounts is a rabbit hole. I've spent too much time, effort, and money trying to make the car drive better without bucking and horrible cabin vibrations, and frankly it has mostly been a waste of my resources.
Don't give up though. I believe that the best approach is to replace all the mounts at once. It does improve the car so much. It may end up causing a vibration, but in my case I chased it down to the diff brace, and then had my mechanic apply a permanent fix. If replacing one mt a time m
Thanks headofjar - All the engine mounts have recently been replaced by someone before my son bought the car along with the timing belt (I've been informed):cautious:.
And now since doing the transmission R/R, 3 out of the 4 mounts and bolts have been re-accomplished as well.

---Other

When I went underneath to start the transmission removal (to replace the clutch), I found the person who did the motor mounts left one transmission mount bolt out, a motor mount bracket bolt out and its transmission casing entry hole chipped off and the other motor mount bracket bolt loose (felt like it was stripped) - (see attached photo).
Not a happy moment for me as I've already bought a ton of parts to replace. 🤬

Luckily, I swapped out a couple bolts and dug one out of my bolt bucket that even though it was a bit too long, I washer-ed it up and the threads finally bit and held.🥳

On the chipped-out one I used some extra loctite on the bolt threads and the mount bracket has some surface area to spread the bolt/bracket load so now I feel more ok with that one.
Sacrilege!! They are such good cars when well looked after and will be much sought after in the future. Your son has great taste. Keep the oil changes frequent and put a nice stereo in it for him)))) with a good clean, 3 piece floor-mats, roof racks, gearshift bushings and shift shroud, headlight bulbs and window rain shields, these cars are useful, look awesome, and are efficient on fuel with great handling, it's not cheap but sorting suspension properly yields a truly great handling car that will get you out of trouble in a pinch.
 
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