4th Transmission mount........Problem???

[z28_Bignick_z28]

Ok fellas i have a new one for yall, in the past year i have gone through 4 transmission mounts, these are the mounts from O'reillys. They are the anchor made from mostly rubber..the transmission was rebuilt 6 months ago just to let yall know, i put one on tue.... and on Thur, its broke..keep in mind i did get on the car but nothing over the top....Suggestions on a problem, or a diff. mount..thank yall


P.S ..I did post a thread in the Tech forum. And it should of been in the off topic.for that i apologize.

[Jeff_in_Atl]

I put one on mine from AutoZone and broke it in 2 weeks. They will not handle it. There have been many issues with the prothane mounts with an automatic transmission. The energy suspension is softer and I would suggest it.

[z28_Bignick_z28]

. The energy suspension is softer and I would suggest it.

were would you reccomend i looked for that

[96FirebirdFormula]

were would you reccomend i looked for that

Solid motor mount did you try that yet?

[Rob B (shoebox)]

If you still want a rubber mount, get an LS1 mount.

[Z Ya Later]

were would you reccomend i looked for that

If you mean where, try here...

Energy Suspension Transmission Mount

[MunsonGTA]

summit racing and probably one of your local parts stores sell the energy suspension tranny mount. there must be a reason you keep breaking them, even a stock unit wouldn't fail in 2 days unless you're doing neutral drops or clutch dumps.

[Injuneer]

Something may be putting exceesive loads on the tranny mount.... possibilities could include:

-weak motor mounts
-incorrect pinion angle
-incorrect alignment of engine/tranny package

The u-joints in the driveshaft work best if the tranny output shaft is exactly parallel to the pinion shaft. To achieve that, the pinion shaft is intentionally pointed downward slightly under no load conditions, so that when the torque arm suspension allows it to move upward under high torque loading the shafts will be in the correct alignment. Get things too far out of alignment, and the u-joints no longer provide a constant velocity, and the tranny output shaft and pinion shaft suffer from cyclic loading that will wear out bearing, seals and u-joints. These forces might tear the tranny mount apart quickly if the misalignment is major.

I have had the same ES Poly mount under my trannies for 12 years.... first under the T56, then the TH400 and now the TH400+Gear Vendor. Pushing 800 lb-ft of torque, and never had a problem with the tranny mount.

[Joe 1320]

Something may be putting exceesive loads on the tranny mount.... possibilities could include:

-weak motor mounts
-incorrect pinion angle
-incorrect alignment of engine/tranny package

The u-joints in the driveshaft work best if the tranny output shaft is exactly parallel to the pinion shaft. To achieve that, the pinion shaft is intentionally pointed downward slightly under no load conditions, so that when the torque arm suspension allows it to move upward under high torque loading the shafts will be in the correct alignment. Get things too far out of alignment, and the u-joints no longer provide a constant velocity, and the tranny output shaft and pinion shaft suffer from cyclic loading that will wear out bearing, seals and u-joints. These forces might tear the tranny mount apart quickly if the misalignment is major.
.

I second that. Do you notice any vibrations at various rpms?

[Jeff_in_Atl]

I just want to reiterate how much junk the transmission mounts are from the local auto parts store. Yes a misalignment could cause a problem but the chances of that and actually checking that are a bit more difficult. GM has made a 1 size fits all transmission mount since I think 1956. That mount from the local stores are fine in a Chevette but they will not hold up to a V8 especially with the electronic transmission that makes it shift harder at full throttle. If you compare the local parts store mount to a GM mount they are a lot thinner where the rubber ties to the base. Get an Energy Suspensions transmission mount and you will never have another problem with it.

[z28_Bignick_z28]

Do you notice any vibrations at various rpms?

Other than the fact that my transmission knocks the floor board when it shifts, i can't notice any other problems, no vibrations.

[MunsonGTA]

I just want to reiterate how much junk the transmission mounts are from the local auto parts store. Yes a misalignment could cause a problem but the chances of that and actually checking that are a bit more difficult. GM has made a 1 size fits all transmission mount since I think 1956. That mount from the local stores are fine in a Chevette but they will not hold up to a V8 especially with the electronic transmission that makes it shift harder at full throttle. If you compare the local parts store mount to a GM mount they are a lot thinner where the rubber ties to the base. Get an Energy Suspensions transmission mount and you will never have another problem with it.

the chevette was actually designed with a v8 in mind. there are plenty of people out there that have made them into drag cars just like vegas and monzas. i saw a show on the history station one time that talked about how GM engineers designed it to put a 305 motor into the car, they just never did it.

[Jeff_in_Atl]

the chevette was actually designed with a v8 in mind. there are plenty of people out there that have made them into drag cars just like vegas and monzas. i saw a show on the history station one time that talked about how GM engineers designed it to put a 305 motor into the car, they just never did it.

I bet no one has an O'reilly or AutoZone transmission mount in their drag Chevette.

[Jeff_in_Atl]

Other than the fact that my transmission knocks the floor board when it shifts, i can't notice any other problems, no vibrations.

If you can't find an Energy Suspension one you can get a prothane one but I would bet you would hate the vibrations from it. Heck if you live in Atlanta I'll give you one. That would at least get you back on the road.

[MunsonGTA]

I bet no one has an O'reilly or AutoZone transmission mount in their drag Chevette.

haha i bet you're right on that. a v8 chevette sounds like a killer sleeper idea to me. or better yet, a chevette with a nice quite 3.8 gn/tta motor.