thumping when launching

[OneEightSeven]

Hello gang. The other day I noticed I have a thumping sound coming from under the seats when I launch hard. Kind of like wheel hop just right under me. I recently changed the auto trans mount, and I jacked the car up to see if it was loose, but I couldnt make the trans budge by hand. Tomorrow morning I'm gonna go to my mechanic so we can lift it and take a better look. Could it be the torque arm bushing?

[steddy]

Re: thumping when launching

Without actually hearing it, I'd say take a look at the torque arm bushing.

[Bird_Of_Prey]

Re: thumping when launching

I recently changed the auto trans mount

I'd be pretty suprised if it was a Torque Arm Bushing.

[cam98aro]

Re: thumping when launching

I'd be pretty suprised if it was a Torque Arm Bushing.

same here, i would suspect the trans mount or exhaust hitting.

[OneEightSeven]

Re: thumping when launching

So yea it was the trans mount. Apparently I hadn't used enough thread lock and one of the bolts came out and the other was on it's way. I guess I just couldn't see it when the car was jacked up, but it was pretty obvious on the lift. I noticed my pinion seal (driveshaft & diff link) was leaking slightly so we changed that out too.

[ssms5411]

Re: thumping when launching

I was going to say usually the trans mount. Either gone bad or bolts backing out. Also sometimes the LCA's when they get loose you'll get alittle pop.

[OneEightSeven]

Re: thumping when launching

so my mount is thumping again.... it was fine for the first few drives.. does anyone sell something that will fix this problem?

**EDIT** Got under the car. It ripped this time, didn't come loose. I traded it under warranty, but here is the question: When I was at my mechanics when it first came loose (when I couldn't see what it was), he mentioned i should have went with an OEM mount. Are the NAPA mounts garbage? Or was my mount just damaged when it came loose before? Should I go OEM or is there someone who sells stronger mounts?

[Bird_Of_Prey]

Re: thumping when launching

Yeah, most of those mounts are junk. I thought the GM 1LE mounts were polyurethane, but could be wrong. I would go with something of that nature.

[cam98aro]

Re: thumping when launching

is this an auto or manual?

[OneEightSeven]

Re: thumping when launching

It's an automatic. Does anyone know the part number for a GM one? I've been trying to find it on gmpartsdirect.

[ssms5411]

Re: thumping when launching

Poly tans mounts and tq arm mounts will last forever and will not make noise , I would def. reccomend them.

[OneEightSeven]

Re: thumping when launching

@ssms5411

where can i get poly trans mount?

[ssms5411]

Re: thumping when launching

Thunder racing, Grand Valley Specialites ((97RS4life) owns it might pM him, you will need to slot the crossmember but its worth it. Their about $20 or so. Theres a writrup on it down below in the write up and submissions which I think people should look through, alot of good info.

[Mark42]

Re: thumping when launching

@ssms5411

where can i get poly trans mount?

Summitracing.com, jegs.com both sell the Energy Suspension poly trans mounts and torque arm bushing. .

BTW, I replaced my torque arm bushing with the Energy Suspension bushing and it makes no noise. Although I read on a number of forums the poly trans mount is very noisy and passes vibrations. Best to stick with the OE trans mount, from what people say.

[Bird_Of_Prey]

Re: thumping when launching

I have an energy trans mount in my swap car and it doesnt make any noise or transmit vibration. Magnus had one YEARS ago that made you think the car was going to shake itself apart.