Hi. I have been having problems with my 350 tranny shifting properly in my 79 Trans am (Olds 403). So I figured I would try a new vacuum modulator. Here lies the problem. When I loosened the bolt to remove it, the bolt broke off of the tranny along with the threads. Person before me epoxied it or something. I used some urban engenuity and put it back together. The tranny is still not shifting right. I called B&M yesterday and the technician said all my symptoms are pointing towards the vacuum modulator. Is there any way to fix it without removing the tranny? any ideas?

(I called B&M because I just recently installed a shift kit)

In case you want to know the symptoms they are -

Reverse is sloppy, will move but only when you feather the gas pedal)

Won't shift to 2nd gear until 4,000 rpm. No matter how you get to 4,000 rpm. I have tried slow and fast. I tried manually shifting it up and it wont.

When you are driving with the shifter in drive position it seems ok (except the shifting part) until you let off the gas pedal. Then the idle drops to 800 rpm (idling rpm) but the minute you push the accelerator it accelerates. There is no clunking or anything like the tranny falling in or out of gear. But, now here's something else. If I place the shifter into low 1 it will whine the gear when you let off the accelerator.

Last thing (sorry kind of long). I disconnected the vacuum modulator and the tranny goes into reverse properly, not sloppy at all. But when you drive, it almost feels like you are starting out in 2nd gear. But shifts worse (if that's possible) than when it's hooked up.

Any help is much appreciated. Suggstions or anything you may have to offer.

Thank you,

Scott

If you can get a hold of a 90 degree angle drill you might be able to drill the bot out with the trany in place. These drills are common in the aircraft industry. They use bits that have a 1/4-28 thread on the end of the bit and come in lengths as shorts as 1/2" so they can work in very tight places. They are not as easy to hold steady so drill at your own risk. It's easier to pull the tranny and drill out the bolt than it is to pull the tranny to remove a broken drill.

BudLight,

I would support the trasmission with a jack and then remove the crossmember. lower the trans just enough so you can drill the bolt out and then re-thread the hole. You might have to go to the next size bolt which would be a 3/8X16 because the guy before you stripped the threads out and that is why he "rigged" it back together.

Keep us posted
Scholman

Use anti-seize compound on the threads so it doesn't happen again.

The threads arn't the only part missing. A piece actually broke off the bell housing. I'm more concerned with trying to determine the shifting problem. Whether or not the vacumm modulator is even causing the shifting problems?

Any ideas?


Thanks for your help,

Scott

If it has a piece of the case broken off your wasting your time doing anything to that case in my opinion. Your shifting problem could very well be cause from this. You'll never know how far cracks my be radiating from the damage until complete disassembly. If a crack happens to extend into a fluid passage it usually causes ether a shifting problem or causes it to slip.

Budlight,

I do not think a missing piece from the Bell-housing will cause a shifting problem. You might have an alignment problem if the missing part of the Bell-housing is from one of the alignment pins.
I thought you meant the flat area near the modulator was broken. That might cause an internal pressure leak. If the hold down hole is just stripped just re-thread it.
Fix one thing at a time step by step and I am sure you will find the problem.

Good Luck
Scholman