Transmission Mounts

[Will]

So I was trying to figure out what the horrendous noise is when my car shifts hard and I noticed that the trans mount isn't actually bolted to the trans. (I have a 1995 LT1, A4) Is this right? Does it really just float over the mount?

[my95z28]

I'm not positve about urs, but it sounds like you lost the nut that threads onto the stud. On mine, my mount was bolted to the bottom of the transmission, then there was a stud coming out of it that went through the crossmember, and that had a nut on it to hold the crossmember tight to the mount. Mine was old and dried and cracked,so I ran up to the local auto parts store and got a much stiffer one for like $20.

EDIT: Although my car is a 6 speed, so i dont know if they will be identical or not.

[JoeliusZ28]

um yea that would definitely be a problem.

[Will]

Yeah, I was just looking at some trans diagrams and it's definately supposed to be bolted down to the crossmember and the trans. I wonder how long it's been effed?

[my95z28]

Thats definatly not a good thing, so get it fixed quick! And don't beat on the car anymore until you do!

[shawnc16]

Poly mount ftw... probably the most common failure of any part from 82-02 no doubt.

[93formulalt1]

Poly mount ftw... probably the most common failure of any part from 82-02 no doubt.

x2! I put one on my Camaro when the stock one went out. . . Great improvement! They're only like $35 too. . .

[badinfluence]

I've read if you use a Poly trans mount you need to use poly motor mounts to avoid increased stress on the bellhousing

[Will]

I've read that too. The mount that's on there looks fine, it's just not attached to the trans. I think I'll wait on the poly until I can do the motor mounts too.

[93formulalt1]

Motor mounts are pretty cheap to upgrade as well, I'm holding off to change the trans mount on the Formula until I can swap the motor mounts as well. Throw a bolt on there and call it a day!

[Will]

Update: All fixed up. The local Chevy dealer gave me the bolts for free!

[JoeliusZ28]

I've read if you use a Poly trans mount you need to use poly motor mounts to avoid increased stress on the bellhousing

I dont believe that at all. The amount of flex the poly mount is reducing is minimal. Im having a hard time wrapping my head around the physics, but Im picturing a bellhousing having to endure a heck of a lot more torsional stress than that anyway.

[Will]

It's basically a triangle, right?

When you put only the one solid mount in, you're basically making a large twisting lever out of the motor/trans with a range of motion equal to the play in the motor mounts. When you run torque through this system it tends to want to turn about the point of the triangle, and if the point of the triangle is a stock mount then it has a little give before it puts undue force on the trans. If it's a harder aftermarket mount, there is less give and you end up applying more force to the tranny. If you replace all three, motion is restricted at the ends of that lever and you don't impart as much force to the third point.

Did that make sense to anyone else?

[shawnc16]

Here ya go.. if ya havent found a mount yet.
http://www.spohn.net/shop/1993-1997-...-Mount-GM.html

[JoeliusZ28]

It's basically a triangle, right?

When you put only the one solid mount in, you're basically making a large twisting lever out of the motor/trans with a range of motion equal to the play in the motor mounts. When you run torque through this system it tends to want to turn about the point of the triangle, and if the point of the triangle is a stock mount then it has a little give before it puts undue force on the trans. If it's a harder aftermarket mount, there is less give and you end up applying more force to the tranny. If you replace all three, motion is restricted at the ends of that lever and you don't impart as much force to the third point.

Did that make sense to anyone else?

I understand that entirely, I just dont see how that is going to hurt anything but the trans mount. I honestly dont feel that the trans mount does much other than keep the transmission in place, there isnt much load on that crossmember at all. Id say its job is just to keep the trans from bouncing around when driveline forces are changing (like your shifting). I mean heck yours has been disconnected for who knows how long, and the only difference you noticed was a sound it made. From working on my car id say the engine mounts have to hold at minimum 75% of the weight - and keep in mind ive got the heavier T56. Furthermore their location has leverage on the torisional force of an engine where a trans mount does not.