I HAVE AN 87 TRANS AM , 305 TPI FUEL INJECTION.. AFTER CAR WARMS UP IT IDLES AT OVER 1500 RPM AND WHEN IT SHIFTS FROM 3RD TO FOURTH IT DISENGAGES AND CAR GOES NOWHERE. I HAVE TO PUT IT IN PARK AND START ALL OVER , IT SHIFTS FINE ESCEPT UNTILL IT TRIES TO SHIFT TO FOURTH...ALSO WHEN I STEP ON THE BRAKES I HERE A HISSING SOUND FROM UNDER THE DASH BOARD. AND I AM NOT SURE BUT THIS CAUSES THE CAR TO IDLE HIGH.....CAN ANYONE HELP?

 

Ok, first, please lose the caps lock.

Anyway... you probably have a vacuum leak from the vent controls. The doors that control the air flow to the vents are vacuum controlled, and there is a plastic vacuum router attached to the back side of the A/C control panel. It sometimes cracks and causes a vacuum leak. That can cause a wierd idle and the hissing noise.

Sounds like your tranny is damaged. I'm not sure if it's just normal slipping, in that case it ought to find fourth gear if you back off the throttle enough. When I say "normal" slipping I just mean the common problem that a lot of folks get... the only real fix is a rebuild. Does it shift 1-2 and 2-3 perfectly? I'd say for now (unless you have $1200 or so) just drive around in D instead of OD. If you want to fix it, you can get a high-performance tranny from Pro-built automatics for around $1250 or so. That's a very good price when you start looking around and seeing that having your current one rebuilt will run you at least $1000 (in my area anyway). Even new ones from GM cost more, around $1500 or so I think. Anyway you've got a few options there. I've heard that rebuilding your tranny yourself is VERY difficult but it can be done, in which case you're probably looking at around $400-$600 for a kit and tools.

That's assuming the tranny is shot. It is possible that there is a single broken part that causes it not to shift into forth, but I don't know enough about trannys to tell you what it would be. Maybe GMTech or someone else with tranny experience will respond.

[This message has been edited by Eggplant Jeff (edited July 25, 2000).]

 

Next time it disengages, slow down and put it into "D" (manual third). If it still doesn't pull, try "2" and eventually "1" and see if it will pull at all. Do you have to put it in park, or can you just come to a stop and then start out again? Does reverse work without putting it in park (coming to a stop of course). Let us know.

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"I used to have a handle on life, but then I used it as a plunger and broke it" -The Wave

ASE Master Tech + L1
Savannah, GA
'87 Trans Am-K&N,Cold air induction, SSM SFC, Flowmaster, 16" GTA rims.
'97 Bonneville SSE
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