slipping transmission

[blazed up]

just wondered is anybody could advise me of the probable cause of slipping transmission 1989 s10 with a 700r4 box fitted put into over drive when cold slips on pull away , put it in drive engages quicker and does not slip , gearbox has had a recent oil and filter change oil still looks good and not over filled .

[sector95]

The 700R4 is a "dumb" transmission in that it does not have any computer controlled inputs to it. What it does have, and it is very critical, is a TV Cable (and no it does not get ESPN2). The TV cable controls a valve in the tranny that determines all sorts of functions (shift points, lock up, overdrive and operating pressures to name a few).

The TV cable adjuster should be located adjacent to the throttle cable connection on the throttle body (I think the '89's had TBI...yes?). Look for a second cable coming off the throttle body that disappears back and down into the lower bowels of the engine bay; that's the TV Cable. If you have cruise control, there may be a third cable but it will typically trace across to a bellows looking thing on the fender well. To adjust the TV cable, push in the "thumb tab" on the adjuster while attempting to slide the cable back (away from the throttle body).... it's a sorta walking and chewing gum kinda thing. If it's a bit sticky, give it a shot of PB Blaster or WD40. You may have to use a large screw driver to push down the "thumb tab" as it has a pretty stout spring. Once the cable is released and slides freely (this will happen when you push down hard enough on the thumb tab) in the adjuster, pull it out or away from the throttle body as far as it will go (usually about 3/4 - 1"). Release the thumb tab. Now open the throttle valve in the throttle body all the way (like if you floored the accelerator). The TV cable adjuster has a ratchet and the TV cable will pull back toward the throttle body as you twist open the throttle valve; there'll be a little resistance as you do this so open the throttle valve with a little vigor. You want to make sure you have wide open throttle to get the adjustment right. And that's it.

Now, there's no gaurrantee this will fix your slipping tranny (the TV cable, if seriously out of adjustment for an extended period of time, can cause terminal damage to the transmission). There is also a vacuum swith, located on the fender near the washer bottle. It will be all by itself, have a single vacuum line running to it and a single wire lead coming off of it. This is the overdrive lock up switch ( I believe it is to prevent OD lockup until the tranny fluid warms sufficiently based on the engine tempurature). Make sure this switch is connected properly and the vacuum line is not leaking (beter yet, just replace the vacuum line).

I hope this helps.

Mike

[bigd7315]

heres some bad news the problem u r having i have had twice and is the bg problem w 700r4 but can be cured unfortunatly u need a tranny rebuild and when you tell them to rebuild it tell them to put in a slight stall converter with a shift kit for towing and put a tranny cooler on it if not already and no more prblems ever but if it slips in over drive and not in drive the fourth gear clutches are worn out