i have a small question about my cars tranny, im new to the site and not sure how to use it, so forgive me if im doing this wrong, but i have no other options... i recently bought a 1992 firebird, its a 3.1l mpfi, with an auto tranny. i know my way around the engine bay pretty well but i suck at trannys, i dont even know what trans is in the car, i (i think its a type of 700r4). i have had the trans looked at, and gathered oppinions and they seem to offer me no help. the car drives/shifts fine when its cold, but about 5 miles after it reaches op. temprature, it starts to unlock the converter on its own. it will lock again if i increase throttle, but as soon as i let off, it unlocks again. as the trans increases in temp, it requires more throttle to lock it up, until i get to 3/4 throttle then it stays unlocked untill it cools. ive been told my tranny is shot, but this is highly unlikely since the lady i bought the car from babied it for the first two years of its life then parked it in storage. i picked it up for $2500 and its in prestine condition. all original.. ive done everything i know to do. changed fluid, replaced tps,etc... sorry for making you read so much but im afraid additional damage will result from this malfunction. this is my first car, and its also my dream car. i saved till my 18th b-day to get it... ANY input would help

 

u may get more help by posting in the transmission section
or by sending a message to dana@probuilt

does the transmission slip at all ?
is the tv cable adjusted properly
is the fluid filled to the right level
check the plug on the side of the transmission for any wires that are frayed and or melted


theres a few things for u to check to start if its not any of those it will get a lil more involed

and yes u have a 700r4 transmission

 

everything that is related/ hooked to the trans seems to be fine, and i dont know if you could call it slipping but as the trand warms it does tend to take a few more milliseconds to switch gears. it changes gears as it normally would, but the converter isnt locking when it gets hot. from reading on here, im told this conv. issue increases heat, which to the best of my knowledge of trannys is very bad.... im a fairly experienced mech. but as i said, trannys are iffy to me.. i just dont know what to do..

 

the ecm controls the converter lockup based on input from various sensors.
inside the transmission there are mechanical valves that can overide the ecms commanded lockup based on throttle position or gear

try adjusting the tv cable first
read this
http://www.tvmadeez.com/article/index.php
about halfway down it shows u how to properly adjust the cable

90% of all 700r4 issues are usually related to improper adjustment of the tv cable

also if tire size or rear end ratio happened to be changed on the car and the correct speedo gears have not been installed this could also cause issues with converter lockup

see if adjusting the cable helps any

if not u may need a new presure switch or lockup soiliniod installed into the transmission , both of which are very simple to do with no special tools needed

 

thank you so much!!! i cant tell you how much sleep ive lost over this without any real answers,, im pretty sure the tv cable is adjusted properly, but ill try again, also, the entire car is more than likely stock, the woman i bought it from wasnt very car-literate, and she bought it brand-new...

 

and this may help diagnosis.. ive had the car since february, and this issue started mid apil.