When shifting aggressively from 1st to 2nd and 2nd to 3rd my car makes a loud THUNK! THUNK! noise. This only started happening a few days ago. I thought perhaps there was a problem with the front suspension, but everything checks out ok. Could my tranny mount be loose/broken? I'll be able to check it tomorrow when I get the car on stands, but in the mean time if anyone has a suggestion I'd be glad to hear it.

 

i would check or replace the torque arm mount if it's stock(older than dirt)also where the thump coming from front middel or rear

 

I was just driving it and it almost sounds like the tranny is hitting the top of the trans tunnel!

 

get under the car and see if you can see alot of rubber cracking on the tranny and torque arm mounts or soft spot.and if you replace with rubber it will be smoother but if you go with poly it will be stiffer with more thumps but good thumps

 

Its too dark to check it out tonight. I'll know more tomorrow.

 

Definitely sounds like the tranny mount. A bad torque arm mount will make a little noise, but a loud thump like the trans hitting the tunnel is almost always a broken trans mount. Replace it with an Energy suspension polyurethane mount. They're well worth the extra money over the rubber ones.

 

I'll second that! I put one on my 87 Formula and it was the best thing I ever did!

 

if it was the trans mount your stick should jump up and down

i've broken three of them, and the last one sprained my wrist. it broke while i was burning around a corner in second gear at 5000 rpm and i had an iron grip on that stick.

 

Yeah, I got her up in the air today and confirmed that it is in fact a broken tranny mount. Unfortunately, I have that weird round tranny mount that costs like $300 from the dealer (no one else stocks it) not the $25 one that 99% of GM RWD cars came with.

 

Here is a pic of the one I have. I grabbed this pic from a post I found after doing a search in this forum (not my picture).

 

That tranny mount is a royal PITA to find. Before you waste any time messing with those, I'd like to inform you of the fact that you can snag a regular type crossmember from any 700r4 thirdgen and a lot of the T-5 thirdgens, and use it with the standard type Energy suspension poly mount. I tried to tell another guy this just a few weeks ago because he had the same goofy mount that you're dealing with, but it was already too late. He'd already looked high and low to find the goofy mount and spent way too much money getting one. Save yourself a ton of headache and just grab a standard type crossmember out of any 84-92 thirdgen in a boneyard, and use it in conjunction with the regular type poly mount. The same crossmember will work for either a V-6 or a V-8 f-body. Trust me on this one!

 

, crossmembers are east to come by in the bone yards, all 84-92 will fit...82's and 83's wont

 

Thanks guys! I was hoping that would be the solution. My local bone yard has several f-bodies most of which are missing their trannies (which will make getting a cross member that much easier!)

 

Woohoo! Went to the wrecking yard today and scored a cross member with tranny mount from an '86 SC for $14!!! Sure enough, it bolted right in!!! Thanks guys!

 

Is it a stock rubber mount? If it is i would buy a polly one, you will rip through that rubber one in no time.

 

Yeah, its the stock one. I'll get the poly one on order real soon, but the rubber one is still better than the broken one!

 

Sweet! Glad we could help you save the money you would've wasted on that other stupid mount!