Write-Up: Filled Rear Motor/Transmission Mount

Wow 86k and a rebuild? I wouldve been pissed! Thats kind of like the engine compartment fires in the 3800s that caused Grand
Prix's to burn up. Mine caught fire after I got out of the car and I had to sit and watch as it burned EVERYTHING under the hood... only to get a kind notice from GM a year later stating for me to take my car in to the dealership for repair to a faulty part that caused engine fires and the service would be performed for free. But what about my car that is already charred? I want another motor at minimum!

The only good part about premature failure of the trans was it was covered at the time under an extended warranty that I bought after buying the car.
Unfortunately I did not know about this site or any others like it so i didn't know that i should have bought some high performance parts for the rebuilder to install. I had the cash at the time but didn't have a clue.
Also the mounts weren't covered by the warranty and i was told they were not available aftermarket, only from the dealer. At that time that was a true statement as I tried searching on my own for mounts to no avail and paid the $600.00 out of pocket for those.
Now we are finding that the aftermarket is finally stepping up to the plate and making new ones for 1/3 rd the cost.
Anyway there were a lot of things i didn't know about availability of performance parts for the Riv back then because anytime you did a search on-line you came up empty. What I have since found out is that the Regal and GP's offer a lot of parts that fit.

Yeah Ive noticed that on some of the other sites such as pfyc. The GP had the same parts as Riviera and Bonneville, although I noticed that some thing were slightly different, such as the 2000 Bonneville I had took the same motor as any other Bonneville or GP but the differential in the transmission was different.

soooo, should I do my write-up of my LF urethane trans-mount yet? The one that eats ALL the torque???

Abaddon wrote:

soooo, should I do my write-up of my LF urethane trans-mount yet? The one that eats ALL the torque???

if you are referring to the one at the front of the tran, then we already have 3-4 options for that one. (i prefer my window-weld/polyurethane filled mount) Most of us need a new rear one, but it's too much of a PITA to get to.
if you are talking about the one accessible from the driver wheel well then by all mean show some pics

Abaddon wrote:

soooo, should I do my write-up of my LF urethane trans-mount yet? The one that eats ALL the torque???

Yes, by all means the more info and documented experience the better.

Mr.Riviera wrote:

if you are referring to the one at the front of the tran, then we already have 3-4 options for that one. (i prefer my window-weld/polyurethane filled mount)

Way to kick me in the nuts lol. Window weld is amazing stuff. Haven't had spare time to do a different one yet, but I will.....oh yes, I will.
I got a blown out front mount from a junk yard and made my current "window" mount. It worked so well I made 2, so now I have a spare.

Apologies for not searching through the millions of posts to view the write-ups.

my bad bro. when you have a chance take a look at the write-up tab at the top, it should be in there along with the rubber mount option, shore 60 version, and the hockey puck mount

Abaddon wrote:

Mr.Riviera wrote:

if you are referring to the one at the front of the tran, then we already have 3-4 options for that one. (i prefer my window-weld/polyurethane filled mount)

Way to kick me in the nuts lol. Window weld is amazing stuff. Haven't had spare time to do a different one yet, but I will.....oh yes, I will.
I got a blown out front mount from a junk yard and made my current "window" mount. It worked so well I made 2, so now I have a spare.

Apologies for not searching through the millions of posts to view the write-ups.

I still haven't found a Write Up with pic's showing what all was done to the mount and what the actual product mfg. name( other than window weld) and P/N is that was used.?
If you have that info, can you post it please.
Thank You

Sure Rick. I'll take some pics of the spare (unused) one that I have to show the finished product if you need. I don't have any Window Weld or the adhesion promoter thats required but I'll get the P/N's for ya...

Link

Yeah when the guy was putting the bolt in the mount I kept having to slightly raise the jack so he could fit it in. I wasnt under the car myself but he said it was a bitch to do. Best $20 I spent.

I found this on Rockauto for $27. Are we looking at a rear transmission mount?



Says it will fit the following:

BUICK PARK AVENUE (1997 - 1998)
BUICK PARK AVENUE ULTRA (1997 - 1998)
BUICK RIVIERA (1995 - 1998)
OLDSMOBILE AURORA (1995 - 1998)

Link: http://www.rockauto.com/catalog/raframecatalog.php

AA,
Do you plan on buying one, fill the gaps with the window urethane and give it a try.
If I didn't already have new ones I'd be willing to give it a try.
If and when I ever make an order from Rock Auto, I have to remember to add it to the list just to see if it fits.
Unless someone else grabs one first and lets us know if it fit's.
I have been told repeatedly that they are only available from OEM sources, but this could be bogus info.
For someone with worn out mounts this would be worth a try. It's cheap enough not to break the bank. I think the tube of urethane cost's almost as much. IDK for sure.

need to replace all mounts soon tho under hood.
today was checking rockauto and...they don't sell anymore motor mounts? noticed only the transmission one.

As i remember they where anyways hell expencive?

Rickw wrote:

I have been told repeatedly that they are only available from OEM sources, but this could be bogus info.

Or the aftermarket is finally producing to meet demand. Not surprising they took this long, there probably weren't many customers for this part until recently.

That was the mount. I needed the bolt that went through it.

Kenneth, you're saying the one in the picture looks like the rear mount on our cars?

I certainly hope this fits our car.
That would possibly be an indication that the Aftermarket is finally coming to the rescue on the $300.00 mounts.
If i needed stuff from Rock Auto, I would buy one just to see. And if its correct for the car, then fill it with urethane and see how it feels compared to the stock near new one I have installed. Actually, I think i remember somebody mentioning using a bonding agent prior to use of the urethane. I'll have to look into that or maybe someone will read this and know.
Even with new ($600.00) mounts, they are made very soft for the luxury Riviera and the motor rocks fore and aft quite a bit on acceleration and deceleration.

Maybe one of these days that I have lift access, I'll just clean the existing mounts and fill with the window urethane and let cure overnight and see what happens.

I just got finished replacing my rear trans mount. What a PITA to do without a lift.
I will say that the mount pictured above does fit, and so does the one i bought from AZ for $50.
I didnt do a full write-up but here are the basic steps i took after much trial and error trying to figure this out.
You will need a good collection of tools to do this btw.

1. Take off both end links from the sway bar.
2. Loosen the 4 bolts holding the rear half of the sub frame on. 18mm
3. Jack the trans/motor up with a 2x4 resting on the trans pan
4. Unbolt the 2 bolts holding the steering rack on the frame. 15mm (i was able to get these from the top with a 4 foot bar, swivel joint and ratchet. They are on VERY tight)
5. Next take off the 2 torx bolts going through the bottom of the sub frame. There is a nut on the other side that i believe is an 18mm you will need to hold.
6. Take out the bolt going through the mount. 18mm on the nut end and 15mm on the bolt side.
7. At this point the trans/motor should be completely supported by the jack.
8. There are 2 final bolts going through the mount bracket into the sub frame. 18mm (you will need to rotate the sway bar out of the way)
9. There is also a 10mm screw holding the power steering lines on the mount bracket that will need to come out.
10. Wiggle out the old mount and bracket. You may need to lower the sub frame and move the PS line a little.
11. The old mount should come out easily b/c its likely deteriorated. The new one may need to be greased and hammered in place. (may work if you have a press)

Reverse the steps for reinstall.

Here is a pic of the old mount in the bracket:

Mine was so bad the center part was completely separated from the rest and would just clunk around under hard acceleration/deceleration and over bumps.


I filled the voids of the NEW mount with polyurethane from a left over 3m tube of window weld. It is very stiff now.


Overall i am Very pleased with how the car is after the install. Idle is surprising much smoother. Shifts are less noticeable and i dont have as much power loss at the shift points. There is more power to the wheels when blipping the throttle at any speed and It amy be my imagination but it feels like the car has less body roll now. Maybe the motor/trans was rocking more than i thought.

Was it worth the 6hrs of work and an aching body? YES b/c i saved a bunch of $$ doing it myself.

Thanks for the write-up. I will be doing this soon. Btw, price for mount has dropped to $24.79 + $5.15 shipping from RockAuto.com. Anchor Part #3065. Total $28.70 out the door with 5% off discount.

It's cheaper there but i needed it ASAP b/c i'll be moving soon and wont have a garage to work in for a little while.

Take notes when you do yours in case i missed something. i was doing a lot of trial-n-error removing bolts trying to find an easier way to get it out.

Boy, the mount sure doesn't look like the drawing in the manual...
I wonder if the expensive, OEM replacement comes as a complete, bolt-in unit.

driver side complete unit is available form AZ for $102

What does the manual look like? maybe the 96 is different than the rest of them?

Eldo wrote:

Boy, the mount sure doesn't look like the drawing in the manual...
I wonder if the expensive, OEM replacement comes as a complete, bolt-in unit.

Yes, the OEM replacement that was purchased for my car during the Trans rebuild for a million dollars comes complete with all the heavy steel ready to bolt in and looks like the complete one Matt posted above.
Don't know if it's the same as the one he posted, but sure looks like it from memory.
I have the remaining metal part that eventually I'll put one of those Rock Auto mounts in with some Black Urethane and see how that feels.
Just another thing to add to the list when I drop the cradle for other repairs. Not urgent since mine was replaced, but the OEM one is too soft and allows for a lot of fore and aft movement.
Need to fill the voids in the other new one that was installed in front also.

Mr.Riviera wrote:

driver side complete unit is available form AZ for $102

What does the manual look like? maybe the 96 is different than the rest of them?

Thanks for the extra photo, I'm sure it will help others along the way.

It was my mistake, I would have sworn that I read yours as 1998 last night... that's what I get for skipping my Vitamin V.
Yes, '95-'96 and '97-'98 are different because of the different trannies - '99 even uses a third one that is the cheapest! To add to the confusion, GMpartsdirect lists 3 different mounts ranging from $50 to $200, but they use the same diagrams for all years...
The only good thing I see in all of this is that the "Drive" mount, which takes most of the abuse, is the front one, which is the easiest to change.

So now I have another question: Do all years use the 4th mount on the drivers side?