Hope someone can help !!!! 95 6.5l with 4l80 trans. The converter will not lock up and also the cruise control stays on for about a quarter mile and then turns off. I just rebuilt the trans, new converter all new electronics in trans. Just replaced brake light switch being the have control over both cc and tcc lock up. Any help greatly appreciated !!!!

 

Going to have to pull codes, i'd bet there is one in there that disables convertor and cruise.

 

Appreciate the reply Josh !!! Only code I'm pulling is I believe #68 which is component slippage.

 

Computer sees incorrect ratio - sets code - disables functions to protect itself. Couple options here, could be a iss oss problem, line pressure could be too low causing slippage, something with the rebuild went wrong (bad convertor, bad parts, assembled incorrectly, valve body malfunction). Do you feel it slip? Is it soft shifting? Does it have all gears?

 

We're going to run some scans on the computer itself to try to determine whether its a computer issue or after computer. Trans works great .all gears and can't actually feel the slip thats kicking the code, but it doesn't require alot of difference between the input and output sensors to kick a code. Thanks again for your reply !!!

 

I would be really hesistant to swap the ecu. if you have a scanner watch rpm vs input speed to get an idea for convertor slip going down the road. We are looking for a bump if you have it on a graph when the code sets. also put iss and oss next to eachother on graphs and do the same. these codes can be very hard to pinpoint if the trans is suspected good. remember though if you fix something then you have a new problem it is 99% something you touched.

 

Right now we're more concerned with getting converter lockup and cruise control to stay working. The slip code I'm not at all concerned about. On the new 4l85's in heavy vehicles such as motorhomes they are reflashing those computers being the programmed slip allowance is not nearly enough for that heavy vehicles.

 

the slip code is more than likely why you dont have lockup or cruise.

 

68 isnt just "component slipping" it is difference between engine rpm and input speed. (hint: convertor).

 

Yeah I know !!! Was trying to rule that out !!! LOL !! On my 3rd converter... Spent the $$-on the billet this time hoping to resolve any issues. Gonna lose my mind if I pull this trans out AGAIN !!!