Motor and Tranny Mount Help

**kool-aide** · 07-08-2007, 03:56 PM

Ok, I did a little search on the forums to see if I could find answers to my questions. I found a little but not enough to feel good.

The shop said my motor and tranny mounts are worn out and weak. The shop said I should plan on replacing them soon, like 6/7 months or so no emergency just plan on it. I have 94k and no clue of previous owner abuse, so I can't comment on the car's shape.

The shop was nice enough to do a little shopping around and said the local dealer is about all they can find without going "performance" related. And as every one knows the local dealer is highway robbery.

What would be a good replacement part for the motor and tranny mounts? I don't know parts or brand names, or even off brand names. I'm looking for a solid part without the worst sticker shock. If I want sticker shock i can buy the mounts from the local dealer and get GM rubber.

My Z is a daily driver with a lead foot pilot. Yes, I have a track near by and sooner or later I will end up spending my ten bucks to take it for a test flight. Since I am not looking to bracket race or trade pinks for winning. I would like a solid performing part for the cost, even if it means GM. As the guy at the shop said if it's not a race car and since no one can see the pretty color of your parts. I wouldn't spend too much money on something you probably don't need.

Thanks

Kool-Aide

**SteveC** · 07-10-2007, 04:27 AM

I would go with the Prothane poly trans mount ($35), and stay with the stock motor mounts.

SteveC

**kool-aide** · 07-10-2007, 01:32 PM

Thanks. Does any one have a prefered vendor for ordering the parts? I think i read n another post a place named thunder road racing or something close to that.

**LETHALxLS1** · 07-10-2007, 01:38 PM

If you like vibration go with the poly mounts if not got with original gm. GM parts direct(one of ls1.coms sponsors)has a website you can click on usually at the bottom of the page. I think the tranny mount is around 60 bucks. Not sure on motor mounts.

**SteveC** · 07-10-2007, 02:01 PM

Originally Posted by BREAKxNECKxSPEED

If you like vibration go with the poly mounts if not got with original gm. GM parts direct(one of ls1.coms sponsors)has a website you can click on usually at the bottom of the page. I think the tranny mount is around 60 bucks. Not sure on motor mounts.

Thunderracing.com or tbyrne.com both carry them as well as Jeg's and Summitt.

I have the poly mount installed in my vehicle for over 3 years with no vibration noises, the trick is to install a thin piece of soft rubber between the mount and the trans cross member.

Do not use the Energy Suspension mount with the bumps, it is more of a generic than the Prothane which is model specific.

SteveC

**LETHALxLS1** · 07-10-2007, 02:25 PM

Alot of people I talked to who bought the poly mounts immediately took them off and went with stock. Just tryin to save the dude some aggrivation.

**maxgee** · 12-27-2007, 08:36 PM

Sorry to wake up an old thread...
Any truth to trimming some of the prothane mounts down to get the engine back to the correct driveline and thus eliminating the vibration?

**kool-aide** · 12-28-2007, 02:31 PM

dunno, the prothane is the same mold as factory just thicker / beefier. I think the engine only move like maybe 1/8 inch, at most maybe even less than that. I'm just going by what i remember noticing.

I talked to the tech guy one day about their mounts. The tranny mount is a correct height replacement.

For me the vibration wasn't from the engine mounts, it was the tranny mount. I did the tranny mount first and the motor mounts like 3 weeks later. I didn't feel any extra vibration at all with the motor mounts. But, the tranny mount made so much racket I doubt i could ever tell.

I've had a good tranny shop look at the car and they say every thing is just fine. Needless to say I have always wanted to have the pinion angle checked again.

Now the vibrations on my camaro are only there at certain speed son the highway and it moves around and depends on how i accelerate. It definitely depends on how well the tires get balanced. tHe better the job the less tooth chatter.

If you want just have the pinion angle checked and adjusted. I'm almost certian the vibrations are from my A4 and not the drive shaft, but i'm no expert. Like a said my troubles started with the tranny mount not the motor mounts.

Or you could spend the extra cash on OEM parts.

hope this helps

**LETHALxLS1** · 12-28-2007, 11:08 PM

Originally Posted by kool-aide

dunno, the prothane is the same mold as factory just thicker / beefier. I think the engine only move like maybe 1/8 inch, at most maybe even less than that. I'm just going by what i remember noticing.

I talked to the tech guy one day about their mounts. The tranny mount is a correct height replacement.

For me the vibration wasn't from the engine mounts, it was the tranny mount. I did the tranny mount first and the motor mounts like 3 weeks later. I didn't feel any extra vibration at all with the motor mounts. But, the tranny mount made so much racket I doubt i could ever tell.

I've had a good tranny shop look at the car and they say every thing is just fine. Needless to say I have always wanted to have the pinion angle checked again.

Now the vibrations on my camaro are only there at certain speed son the highway and it moves around and depends on how i accelerate. It definitely depends on how well the tires get balanced. tHe better the job the less tooth chatter.

If you want just have the pinion angle checked and adjusted. I'm almost certian the vibrations are from my A4 and not the drive shaft, but i'm no expert. Like a said my troubles started with the tranny mount not the motor mounts.

Or you could spend the extra cash on OEM parts.

hope this helps

Dont you need an adjustable torque arm to adjust the pinion angle

**kool-aide** · 12-29-2007, 04:19 PM

don't know, but that would make sense, i think. I was just suggesting that if some one thinks the poly mounts raise the engine (or lower) it toomuch they should look into changing the pinion angle.

I was watching one of those car shows on Spike TV. They were talking about pinion angle on the GM, Ford and Dodge cars and how Ford and Dodge had the engine offset from center and GM was centered but adjusted the angle by height instead.

And then they talked about wearing our the needle bearings, blah blah blah. You know how those shows are. They give you 30 seconds of info and then leave you hanging, like physics. do this and this and here is the answer, but what about all that middle stuff.

personally my car had minor shakes on the highway to start. The poly tran mount just highlighted all that in one big seat of the pants bundle. Not too mention every one kept asking if I had a new drive shaft. They said it looked too clean to be that old. Maybe someone replaced it and never botherd to do a thurough job, who knows.

All I can say is my motor mount install was a real challenge and I never saw a diff in car vibrations. Like I said, the tran mount is what made the diff in my car. Every car is diff, so good luck and if your that unsure just spend the cash on OEM.

Either way get ready for some serious patience and time with the polies and take it from me. Don't cross thread or fowl up the threds on the k-member. You will end up in it deep and have to pay your way out.

**LETHALxLS1** · 12-29-2007, 04:25 PM

Your driveshaft is probably aluminum-thats why they kept saying it looked so new. The steel ones rust. My z/28 has the aluminum DS.

**kool-aide** · 12-29-2007, 04:47 PM

is it made by some one or some where called riverside? I saw a sticker on it once, and I think it said riverside.

**0rion** · 12-29-2007, 11:56 PM

you have an aluminum driveshaft. I bet if you went back to a stock mount it would cure your vibrations. Poly mounts will transfer more vibrations into the car.

**Fastcar** · 12-30-2007, 04:54 AM

Just out of curiousity, how much did it cost to have the trans mount replaced and the motor mounts replaced (labor for each job, I know the parts will be cheap compared to the labor costs). How involved a job is it? I have an A4 trans and get a funny noise/vibration under acceleration which immediately goes away once the trans upshifts to the next gear and the RPMs drop. The noise only reappears at 70+ MPH. My car is a 2000 T/A, just turned 100,000 miles and I suspect that I'm due to have these jobs done. Thanks!

**sunsetorangess** · 12-30-2007, 05:34 AM

Labor is free when you do it yourself, all you need is some simple handtools and a floor jack.
J

**LETHALxLS1** · 12-30-2007, 01:37 PM

Motor mounts are a little more involved-but the trans mount is a 10 minute job.

**kool-aide** · 12-30-2007, 05:29 PM

Originally Posted by 0rion

you have an aluminum driveshaft. I bet if you went back to a stock mount it would cure your vibrations. Poly mounts will transfer more vibrations into the car.

The funny thing is I asked how much and every kind of waffled. I'm pretty sure going back to the OEM would make a huge diff, but I can live with it. It has gotten a tad better over the few months. One guy said to give it time it would subside a little.

When My car hits that sweat spot it can literally shake fillings from your teeth. I drove a PT cruiser that did it at 55 and one that did it at 45. I always knew it had a suspension problem but Chrysler said I was nuts and told me to beat it. Funny thing is many, many PTs had this problem. It is a sad day of morning to think one of our own American icons falling apart, thankfully they were sold, lol...

Any way the shakes at 75 or 80 is not worth it to me right now to pour endless money trying to make it a little tamer. I did that with two PTs and learned to just deal with it, lol...

**kool-aide** · 12-30-2007, 05:42 PM

Originally Posted by Fastcar

Just out of curiousity, how much did it cost to have the trans mount replaced and the motor mounts replaced (labor for each job, I know the parts will be cheap compared to the labor costs). How involved a job is it? I have an A4 trans and get a funny noise/vibration under acceleration which immediately goes away once the trans upshifts to the next gear and the RPMs drop. The noise only reappears at 70+ MPH. My car is a 2000 T/A, just turned 100,000 miles and I suspect that I'm due to have these jobs done. Thanks!

The place I go is 85 bucks an hour and they are straight up serious professionals and real decent family business. As I recall this was the break down on OEM parts

1/2 - 1 hour on tran mount
3 - 3 1/2 hours on motor mounts

they just gave a 4 hour total so i figure tran mount has to be close to 1/2 hour

I did the tran mount myself on jack stands in my garage, no big deal. What took me the lonest and gave me the worst trouble was torquing the new nuts down. For some reason the set of bolts I got couldn't hold 75lbs. It twisted pretty evil and snapeed some where around 65-70 lbs. Prothane was very nice an FedExed a new set no charge. Personally I have no idea why they used studs and nuts. Maybe it was to give a universal fit.

The motor mounts where pretty aweful for me. I had a ton of bolts siezed up bad. I strong urge the use of PB Blaster and a long good soaking first. And make sure to pull out that O2 sensor on the driverside. On a 99 you can't get the stand out with it in.

Oh and I figured out you need to have both poly motor mounts in before you can bolt to the k-member. I fowled the threads on drivers side and had to get the shop to chase them out. Also those clam shells suck without a drill press. I spent a couple of hours drilling out just one set of bolts, just blast the music and take your time, lol... no heavy drinking though.

funny my bill from the shop to put in OEM was about 620 for total job. I blew 400 on getting my threads chased and having them install the passenger side, lol... I tried my best to get the guys to giggle and laugh, but they are pretty decent upstanding guys, still i thought it was histerical. They didn't bill me for all the time, that was cool.

**kool-aide** · 12-30-2007, 05:54 PM

Originally Posted by Fastcar

Just out of curiousity, how much did it cost to have the trans mount replaced and the motor mounts replaced (labor for each job, I know the parts will be cheap compared to the labor costs). How involved a job is it? I have an A4 trans and get a funny noise/vibration under acceleration which immediately goes away once the trans upshifts to the next gear and the RPMs drop. The noise only reappears at 70+ MPH. My car is a 2000 T/A, just turned 100,000 miles and I suspect that I'm due to have these jobs done. Thanks!

well my shop doesn't really like install non-OEM parts. They always know bad things will happen. and they don't like giving their customers bad news. even when I practically told them here is a blank check have fun, they did a walk through estimate with me, looked at the car, sat with me for like 20 minutes.

i would strongly suggest you go to a place you can trust and is willing to take the time to do a 1st class pro job. motor mounts ain't cheap to put in and 85 bucks an hour is not half bad in my town. You get what you pay for.

i can't say much about your funny noise or vibration other than i have been there with a couple of diff cars. I can only replace the parts if they are bad. try match balancing the tires. It can help, but it is no cure by any means. Only change one thing at a time, like tran only ot motor only. Changing too many variables at once won't get you answers.

I know for me my car feels diff based on air temp, how I accel to highway speed, and what gear i'm in. 4th gives the problem, but shift or hammer it, the problem changes. when people say you can feel more with poly, holy moly you can FEEL MORE...

that's why i said if you have any doubts just buy OEM. I lived with my PT Cruiser problems for five years between the two. I was in the stealership 2-4 times a month. It drove me nuts. If your picky about a smooth ride, cuz i sure as heck am, then be sure you know what you're getting into.

One day I will investigate how to smooth out some of my car vides on the highway. I know I can't make them go away, but I bet I can take a tiny edge off of them. I just don't feel like spending the oney right now. I have other things to fix and goodies to buy, lol...

good luck, and get a written estimate first...

**kool-aide** · 12-30-2007, 06:00 PM

I agree tran mount is about an hour tops, cuz you need to jack, tear down, get the poly mount setup, blah blah, done.

just be prepaired to snap a bolt if you over torque or get a bolt that can't handle the lbs. The book calls for 79 lbs on that bolt. Personally I don't think it can handle more than 70 lbs tops. Prothane states it can handle OEM specs, mine didn't and they were surprised. I have mine at 65 lbs right now, had it at 45 lbs for a couple of months and then inched up by 5s. My car sees plenty of romp and stomp and body shakes. THe mount is still there and the bolt is still on, as rachael says good to go yum-oh.

good luck man.