Grinding Grizz!

[willwren]

Not looking to step on toes or disprove anyone. Please take this as constructive and helpful only.

I have seem 6-10 of the TA mounts go bad on various vehicles. My own personal mount is shot after only 20K on a fresh mount. Other respected folks on this forum have mentioned their mount being replaced many times as well. The TA mount is the only mount absorbing the desire of the motor to torque on the passenger side of the vehicle. When it is bad the engine side bracket can hit the body side bracket, metal on metal transfers some engine vibration to the body. Currently my mount is in need of replacement.

Paul, here in the states that front mount is $45 from Rockauto, the rear trans mount $11, and the TA mount is $45. Those are not discounted prices. It's unfortunate that you live in Canada when it comes to prices on parts.

If I were to rank my experiences with mounts failing on the 92-99 B'villes it would look like this:
1. Front trans mount
2. TA mount
3. Rear trans mount
4. Dogbone mount.

X 2

I'm betting we're seeing some type of environmental difference here. Speaking for at least 2 or 3 dozen 92-99's out West, it's not an issue. The mode of failure in the NE may be due to conditions/climate, etc.

Who's toes got stepped on?

[99ssei]

Getting back on topic....
I found this article that might help figure out he grinding noise:
http://consumerguideauto.howstuffworks. ... ille-2.htm

The article (published 2/20/08) gave some "Trouble Spots" for the Bonnevilles (92-99):

Engine noise: Bearing knock was common on many 3.3- and 3.8-liter engines due to too much clearance on the No. 1 main bearing. (1992-94)
Engine noise: A rattling noise from the engine when the car is started after sitting is often caused by automatic-transmission pump starvation, or a sticking pressure-regulator valve. (1992-95)

[2000Silverbullet]

You described it perfectly. Take a closer look at the mount. There is the outter shell and right inside is the metal the rubber is adhered into.. Is that metal rnner ring moving ouf of the outter shell? This is quite common, also common is the rubber cracking and allowing the front of the motor side bracket to hit the body side mount outter shell. The dogbone plays a small part in the overall mount situation and is usually not to blame for noises or issues.

I understand exactly what is happening, what has happened and how it happened.

Deepest appologies to Boosty for ever doubting his vast knowledge.


At rest the shock absorber front transaxle mount huge rubber block is in compression. When the engine torques, it rotates towards the firewall and this places tension on the huge rubber block.
The shock absorber controls the rate of movement to prolong the life of the rubber and its bond.

When the shock wears after 280,000 km (170,000 mi) the rubber fails and tears away from its metal bond.

This allows excessive movement or rotation about the drive axis, forcing the Torque axlis mount bracket to pound the inner sleeve of the rubber mount towards the firewall. This moves the rubber portion inside the sleeve on the front part so the the bracket now hits the metal part of the outer shell.

I temporarily fixed a piece of rubber to act as a cushion until Vic pays me the $208. for the mount.


Took it out for a drive today to pick up the part and OH MY GOSH! This thing has got its torque back.

Now I know why Bill beats me across the intersection sometimes.

Tires are next on the agenda.......... One of his tires has a screw head imbedded in it and the others are bald.

[BillBoost37]

While the bad front trans mount couldn't have helped the TA mount, I'm not sold that would be the only contributor to killing it off. Being that the Grizz is basically the same mounting setup as my 97. And I have been running the below limited movement mount (needed to clear headers) since before changing the TA mount. Currently my TA mount is in need of replacement. On a side note it came from Napa, and looked to be the same quality as the original from GM.

Most likely the higher km's, age and right foot did the majority of the damage.

Another thing I found in the 97 and haven't confirmed with other years yet is in the below picture (mostly upside down) the mount has a space that would be located above the main bolt hole through it's center if the mount were in the car. This space in my car has a piece of rubber pushed into it. The new mount did not come with that piece and many other cars I have looked at don't have it. It may be an additional dampener to take up space.

Does anyone have a picture of where the 92-95's engine side mount bolts up to the engine? I have some interest in comparing it to the 96-99 locations.

[willwren]

Paul, the bad front trans mount likely stressed the TA mount beyond belief. Something to remember.

And the bald tire? Let me guess. Left front (in metric, that would be the tire on the driver's side that goes out the driveway first when in D, not R). PM me if that's the right one.

[2000Silverbullet]

I ordered the mount from GM dealer. He told me the GM part was $250 but if he ordered one from Napa it was only $185 plus tax so I got the Napa part.

If I had ordered one from Rock Auto....which I surely will next time.....it would have cost me about $100 to my door.

All 4 tires are bald. I had to move the front two to the back a couple months ago.

Ya, I know his Bullet genes give him the heavy foot that causes all these failures.................


....as he was leaving tonight with a full tank of fuel, for a Friday night out, I watched from around the corner........


.....he stopped briefly as soon as the car straightened out so as not to induce the one wheel smoke show..........



....and then he squealed out , testing the temporary rubber cushion that is now surely to be mashed into gum like consistency.