Motor mount cross compatability

Hi all. I just picked up a 99 Riviera with the L67 and on the PPI my mechanic indicated that one of the motor mounts is starting to look a little wonky. She also informed me that they're no longer in production (seemed to be confirmed looking at rockauto). Does anyone know if there are there any other vehicles with the same mount or is it specific to the Riviera?

crunk04gtp wrote:

Hi all. I just picked up a 99 Riviera with the L67 and on the PPI my mechanic indicated that one of the motor mounts is starting to look a little wonky. She also informed me that they're no longer in production (seemed to be confirmed looking at rockauto). Does anyone know if there are there any other vehicles with the same mount or is it specific to the Riviera?

You have to say which mount. Some of the mounts are on other GM cars, some not.

LARRY70GS wrote:

https://rivperformance.editboard.com/t12248-what-do-we-do-for-motor-mounts-now?highlight=motor+mount

https://rivperformance.editboard.com/t882-faq-engine-transmission-motor-mounts?highlight=motor+mounts

Awesome! Seems like just what I was looking for. I've always thought of mounts as basically wear items. Are people having luck finding decent used ones?

albertj wrote:

You have to say which mount.  Some of the mounts are on other GM cars, some not.  

Interesting. The only vehicle I've done motor mounts on before both sides were identical. I'll go out and take a look later today to verify which one.

crunk04gtp wrote:

LARRY70GS wrote:

https://rivperformance.editboard.com/t12248-what-do-we-do-for-motor-mounts-now?highlight=motor+mount

https://rivperformance.editboard.com/t882-faq-engine-transmission-motor-mounts?highlight=motor+mounts

Awesome! Seems like just what I was looking for. I've always thought of mounts as basically wear items. Are people having luck finding decent used ones?

albertj wrote:

You have to say which mount.  Some of the mounts are on other GM cars, some not.  

Interesting. The only vehicle I've done motor mounts on before both sides were identical. I'll go out and take a look later today to verify which one.

Yeah you're in for a stunner. The Riv has the transaxle and engine bolted together as a unit, and there is one engine mount, bolted to the passenger side of the engine and the inner fender. This mount bears no weight, it holds the engine in place against its own torque, kind of like dogbone upper mounts are intended to do. It actually does nothing except on acceleration, deceleration and reversing, pretty much.

There are three mounts on the transaxle, a pretty beefy one in the drivers side fender well and the other two on the front and rear subframe crossmembers respectively. It is usually the mounts bolted to the crossmembers that die, I am on my third set. I replaced the one in the drivers side fender well maybe couple years ago. I have never replaced and do not expect to have to replace the front mount.

Some but not that many other GM cars share these mounts. The Park Ave and Aurora share the rear transmission subframe mount. The front subframe mount and the engine mount are one-offs for the Riv. The drivers side transmission mount was redesigned twice, different years use somewhat different mounts.

If you're willing to do the work, you can make up mounts using crapped out mounts (to get the metal hardware) and 3M window weld or pourable polyurethane in the durometer of your choice. Because it's not worked hard, the front engine mount is not a bad bet from a junkyard. The reason that would even need replaced would be if the transaxle mounts were allowed to wear out, then that engine mount gets whacked pretty badly and fails also. The subframe mounts I've had to replace every 5 years or so. It would have been good to use a liquid-filled puck instead of those things and make them somewhat easier to replace, for instance by using 2 smallish ones side by side on the rear of the front subframe so you could replace by unbolting one at a time. Thinking about it, a similar arrangement could fit up front.

Are the motor mounts from a 95 and a 97 interchangeable? I've tracked down a 95 about 4 hrs away but mine is a 97 and I know there were some variations. To clarify I mean the passenger side motor mount.

Derrick_7666 wrote:

Are the motor mounts from a 95 and a 97 interchangeable? I've tracked down a 95 about 4 hrs away but mine is a 97 and I know there were some variations. To clarify I mean the passenger side motor mount.

Look in GMPARTSDIRECT.COM or the on-line OEM parts seller of your choice, and see if the mount in the corresponding position in the 1997 and 1995 parts on-line catalog has the same number.

They seem to be the same. Thanks!

Is there somewhere I can buy the rear trans mount new? Or is that something I need from a donor car too?
Part number 22178776 to be precise.

Maybe?, this can't be right, http://oemcats.com/oem-parts/22178776.html

Superseded Part ,

https://www.wholesalegmpartsonline.com/productSearch.aspx?searchTerm=%2022173114&ukey_make=1022&ukey_model=14446&modelYear=1998&

LARRY70GS wrote:

Superseded Part ,

https://www.wholesalegmpartsonline.com/productSearch.aspx?searchTerm=%2022173114&ukey_make=1022&ukey_model=14446&modelYear=1998&

This pricing tells me they are getting ready to obsolete this part. Get it while you can. Be advised it does not fit exactly like the original but once you figure it out it's fine. If you have trouble I might be able to send you a picture of it mounted on my car.

It says this product is no longer available

Derrick_7666 wrote:

It says this product is no longer available

Ask your GM dealer if they can get one from Vintage Parts.

Albert,
I have to disagree with trying to get a mount, especially the rear mount from GM Vintage.
Shortly after buying my 98 I needed a trans rebuild and the mount in the rear, what I'll call the Trans mount, was $600.00 + from GM at the time. Was told there were no aftermarket parts so I bit the bullet.
Later in life, when I needed to replace the whole front cradle I was able to buy the rubber parts (mounts) from Anchor.
Was able to remove the rubber part and replace it for about $25.00 plus I bought a tube of 3M Window Weld and filled the voids. I believe the addition of the Window Weld contributed to a longer life of the rubber part of the mount. The Urethane, regardless of the Durometer, made the mount more impervious to deterioration due to oil and/or any other contaminates.
If you don't mind a more sensitive feel in the gas pedal then the Urethane is a good way to extend the life of a new mount.
When the front cradle was out I replaced both the (rear) Trans mount as well as the front mount that attaches to the radiator support on the drivers side.
Regarding the large one on the passenger side, I can't see that one needing replacement. It would take a lot to require that one to be replaced.
If I can find the P/N's of the rubber mounts I bought I'll post them. But there should be a thread with those numbers in it.
Best regards to all. Hope everyone and their family's are healthy.
Rick

Rickw wrote:

Albert,
I have to disagree with trying to get a mount, especially the rear mount from GM Vintage.
Shortly after buying my 98 I needed a trans rebuild and the mount in the rear, what I'll call the Trans mount, was $600.00 + from GM at the time. Was told there were no aftermarket parts so I bit the bullet.
Later in life, when I needed to replace the whole front cradle I was able to buy the rubber parts (mounts) from Anchor.
Was able to remove the rubber part and replace it for about $25.00 plus I bought a tube of 3M Window Weld and filled the voids. I believe the addition of the Window Weld contributed to a longer life of the rubber part of the mount. The Urethane, regardless of the Durometer, made the mount more impervious to deterioration due to oil and/or any other contaminates.
If you don't mind a more sensitive feel in the gas pedal then the Urethane is a good way to extend the life of a new mount.
When the front cradle was out I replaced both the (rear) Trans mount as well as the front mount that attaches to the radiator support on the drivers side.
Regarding the large one on the passenger side, I can't see that one needing replacement. It would take a lot to require that one to be replaced.
If I can find the P/N's of the rubber mounts I bought I'll post them. But there should be a thread with those numbers in it.
Best regards to all. Hope everyone and their family's are healthy.
Rick

The front and rear transmission mounts (on the cradle) are still available through Rockauto.com.

I am not confident OP is going to get anywhere with Vintage Parts BUT their stock changes and I am confident that it does not seem to hurt to ask.

I still think getting a JY unit is a good approach for the passenger side motor mount, they don't work real hard. In 20-odd years I've only seen one with a problem, and it seemed to be that the other mounts had been wack a long time and my guess is the driver was a leadfoot.

Last time I saw the drivers side transmission mount there were two NOS on eBay. I bought mine from the dealer, after shopping, the pricing was not much different from what I was seeing elsewhere (eBay) and they were not available on RockAuto.

You are of course correct about filling the mounts with WindowWeld.

I'd mulled over making a liquidfilled mount or having a bracket machined to put in someone elses (there are a bunch out there).

Wow, I was not expecting these sort of part availability issues from a 20 y/o GM. The first car where I've run into out of production parts is my 37 y/o MB and it's only oddball stuff you come across when doing a restoration.

I actually can't see issues on any of the mounts, so it's just the mechanic who did the PPI saying this. I'll try vintage parts but it sounds like I should be keeping an eye out for these things used? I've always thought of motor/trans mounts as wear items but I guess if they're NLA you gotta get creative.

crunk04gtp wrote:

Wow, I was not expecting these sort of part availability issues from a 20 y/o GM. The first car where I've run into out of production parts is my 37 y/o MB and it's only oddball stuff you come across when doing a restoration.

I actually can't see issues on any of the mounts, so it's just the mechanic who did the PPI saying this. I'll try vintage parts but it sounds like I should be keeping an eye out for these things used? I've always thought of motor/trans mounts as wear items but I guess if they're NLA you gotta get creative.

It would be wise to get the PPI mechanic to state whih mount he/she was talking about.

GM older parts are easier for the very long running platforms (RWD F/S CBOP, the various Camaros).

Otherwise, parts availability issues come up promptly when the platform of concern hits 10YO. For these G bodies it got bad enough in 2008-9 and worse 10 years after they ditched the G altogether (it was under the ParkAve/Lucerne). Aftermarket is not bad for wear parts (shocks/struts) but lousy for parts that were 'life of the car' assuming that life was 10 yrs/150K miles.

My Buick Dealer parts printout shows the "front" mount as part# 22201114 and readily available on ebay. And the "rear" mount is part# 22201116 which is also readily available on ebay. Not sure why your print out shows part# 22201115.

I bought the last remaining driver's trans mount in the country using a Buick Dealer parts search. it is part# 22178776 and not available anywhere. There are lots of "options" showing up, so when mine arrives I'll see if I can compare it to anything on the web to see if there is a replacement from another vehicle.

It would be interesting to see if brackets could be moved such that the '99 mounts would fit on the '98.

I think the cradle on the '99 is different. Meaning it has different holes for the new style mount.
Personally, I don't like the newer design. They break in half internally.

Abaddon wrote:

I think the cradle on the '99 is different. Meaning it has different holes for the new style mount.
Personally, I don't like the newer design. They break in half internally.

I'd really like to fabricate brackets so the front & rear transmission mounts could be replaced with puck type mounts such as found on certain old RWD volvos (the 240) or the liquidfilled type found on the 3.0 V6 Honda perhaps.