700R4 - 3rd gen experts please!!!
Thread Starter
Joined: Apr 2005
Posts: 2,169
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From: Dallas, TX / Boston, MA
700R4 - 3rd gen experts please!!! i know this isnt a 3rd gen forum, but many of the same principals apply and there are plenty of smart people in here, so i figure i'd give it a try!
i have an 88 GTA that i got a little over a year ago. it sat for a year before i started working on it, and i drove it for about two weeks before this problem started. over that year, i took it for a lap around the block about 4 times just to let the fluids cycle in it.
the car wont go into reverse at all (acts like it's in neutral), and when in drive, it will shift high, like around 2500rpms under light acceleration. i have not driven it over about 20mph since this started, so i dont know the behavior in anything past 2nd gear.
it started doing this all of a sudden, no symptoms leading up to it. I will state that it started after i was playing with setting my throttle position sensor (TPS), so i'm wondering if i shorted something out. i was told, however, that the 700R4 on an 88 f-body is 100% mechanical and has no computer controlls, so my theory might be worthless.
I checked the fluid today, and there is fluid in there and it is the proper color (not burnt)
i have an 88 GTA that i got a little over a year ago. it sat for a year before i started working on it, and i drove it for about two weeks before this problem started. over that year, i took it for a lap around the block about 4 times just to let the fluids cycle in it.
the car wont go into reverse at all (acts like it's in neutral), and when in drive, it will shift high, like around 2500rpms under light acceleration. i have not driven it over about 20mph since this started, so i dont know the behavior in anything past 2nd gear.
it started doing this all of a sudden, no symptoms leading up to it. I will state that it started after i was playing with setting my throttle position sensor (TPS), so i'm wondering if i shorted something out. i was told, however, that the 700R4 on an 88 f-body is 100% mechanical and has no computer controlls, so my theory might be worthless.
I checked the fluid today, and there is fluid in there and it is the proper color (not burnt)
No reverse and late shift sounds like you have a broken sunshell , Its not that its shifting so late its just waiting till time for 3rd gear shift , Second power and reverse are both dependant on the sunshell and they are notorious for breaking in the 700r4 and the 4l60e . its gonna have to come apart or be replaced ,
performabuilt
performabuilt
Thread Starter
Joined: Apr 2005
Posts: 2,169
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From: Dallas, TX / Boston, MA
eek! 
if that is indeed the case, would it be safe to drive to a tranny shop, or would it be in my best interest to get it towed?
is it also possible that there is an issue with my TV/detent/kickdown cables? i forgot to mention that the same day i was adjusting my TPS, i was also sitting on top of the motor to change my oil pressure sender. its entirely possible that i kicked the cables by accident.
if that is indeed the case, would it be safe to drive to a tranny shop, or would it be in my best interest to get it towed?is it also possible that there is an issue with my TV/detent/kickdown cables? i forgot to mention that the same day i was adjusting my TPS, i was also sitting on top of the motor to change my oil pressure sender. its entirely possible that i kicked the cables by accident.
Thread Starter
Joined: Apr 2005
Posts: 2,169
Likes: 1
From: Dallas, TX / Boston, MA
checked the TV and shift linkage last night
TV appears to be operating fine, and the shift linkage looks ok, but i'm not 100% sure i checked the linkage correctly. i loosened the nut, put the shifter in neutral, then verified the shift lever was in 'neutral' (i put it in the middle notch, pointing down), then tightened it back up.
i did notice that when i try to put the car into reverse, i hear a noise from the underside of the car that sounds similar to the sound you'd hear under the hood when the fuel system pressurizes. maybe some fluid passage is just sludged up from the car sitting for a year and it just needs a filter and flush...
TV appears to be operating fine, and the shift linkage looks ok, but i'm not 100% sure i checked the linkage correctly. i loosened the nut, put the shifter in neutral, then verified the shift lever was in 'neutral' (i put it in the middle notch, pointing down), then tightened it back up.
i did notice that when i try to put the car into reverse, i hear a noise from the underside of the car that sounds similar to the sound you'd hear under the hood when the fuel system pressurizes. maybe some fluid passage is just sludged up from the car sitting for a year and it just needs a filter and flush...
if it sat that long maybe a valve in the VB is seized up. i recomend pulling the pan and dropping valvebody and checking it. watch when you drop it out though there are these little checkball jobbers that are really easy to lose. when you put it back in just hold the checkballs in with transjel or petroleum jelly
no reverse is a mechanical problem period ,
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Joined: Apr 2005
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From: Dallas, TX / Boston, MA
just to update the thread for anyone following it or searching for this info in the future:
i got it rebuilt. and it was indeed the sun shell that was broken.
i got it rebuilt. and it was indeed the sun shell that was broken.
