there is now an 1/8" crack on the back of my transmission, 1/2" in front of the transmission mount. it spans the width of the tranny from top to bottom on the driver's side. i have a prothane poly trans mount.

i was in overdrive @ appx. 140 mph when this happened. the car was pulling smooth and i had no noises prior to the incident. i heard / felt a thud, which was immediately followed by billowing smoke and a whirring noise.

wtf caused this?

 

well something came apart and sounds like it craked the case and those mounts can brake trannys they dont let it give enugh and cause too much vibration in the tranny

 

ttt.....

 

Do you have the torque arm bolted to the tail housing? We see alot of these housing's broken on f-body cars. Relocating the torque arm mount might help. Have you lowered your car or felt any vibrations? You probably should have your driveshaft length checked and balanced.

 

it is the factory torque arm and has not been off the car. i would consider a chassis mount torque arm, but my exhaust prevents that route.

the car is not lowered (stock z28 springs/shocks) and the only vibration i noticed came immediately after installing the prothane trans. mount.

i had plans of switching to an al driveshaft from another ls1 car this week, anyway.

do you think anything else is damaged, or just the housing? i am going to take everything apart tomorrow and hope for the best. i am afraid that much more is damaged than just the housing itself.

 

With any luck a housing will fix it. At 140mph it's a crap shoot! I guess you'll have to see what happens. I would think about re-doing your exhaust to relocate your torque arm. If the trans needs to done feel free to give us a call. Good luck, Vince.

 

Steel driveshaft I bet. Change it to the aluminum one. Steel driveshafts will even crack them after relocating the tq arm.

 

Sean I have tons of 4L60E parts laying around the shop. Get me pics of exactly what broke and I'll see if I have it. If need be, my trans is still laying on the ground so you could borrow mine till you get a new one.

Also you might want to look into the BMR or UMI torque arm relocation kits.

 

thanks for the replies guys. i will post pics after i get some, i am in the process of disassembly now.

thanks for the offer james, i appreciate it. nathan has a 4l60e sitting on his garage floor that i will take the housing from. if the housing is the only problem, i will replace it with his just so i can run this weekend, then buy a new one and replace whatever else i think needs it, as well.

also, i've already given the exhaust a lot of thought. i will change the housing, swap to an al driveshaft, and replace my prothane mount with a stock one. if i have this problem again, everything from the converter back is getting replaced, and a chassis mount tq arm is going on. i have very little patience with things like this.

 

one of our crossmembers will cure the torque arm load issue and clear the exhaust
http://www.converter.cc/drivetrain.htm
the 3.73 gear and Propshaft RPM at 140 in OD are the cause with the stiff poly mount

 

so it was worse than i thought, it was completely separated from the trasmission 360* around. thankfully the output shaft looks good and no other damage occured. i am leaving to get another housing right now. hopefully it will be up and running soon.

 

Dayum!!!

 

Now that's some tranny ownage.

 

That's impressive!

 

the housing was the only damage. i replaced it with another, swapped from a steel driveshaft to AL, installed new u joint and tailshaft seal. it's fine again. w00t!

moral of this story: poly trans mount > stock rubber motor mounts

 

Pure!!! Looks like you where havin fun!!!

 

hell yeah! i have a stack of timeslips literally 2" thick. been through a couple sets of tires so far this year.

 

I had the same thing happen to mines but not THAT severe. 6 inch hairline crack on the bottom. The stock bushing was shot (2 pieces), the shop replaced it with a poly bushing.

 

Awesome photos of damage. Where were you when driving 140 MPH?