I believe the tranny is going in and out of lockup continously as i drive by the rpm varience of about 200 rpm. Any info on the lockup switch and whats involved in replacing it or other idea as to the nature of the problem...anyone?

I believe the tranny is going in and out of lockup continously as i drive by the rpm varience of about 200 rpm. Any info on the lockup switch and whats involved in replacing it or other idea as to the nature of the problem...anyone?

Your in luck my 99 OBS C1500 has been doing it since 110,000 miles. Thats what it's doing locking and un-locking mine does it from 30mph to about 55mph then its normal.

I took it to my transmission guy and he said it was a valve in the trans. that was worn out. And he quoted me 100 bucks or so to fix it. Nothing major.

But I said Fuck it and just drive it! Now I have 193,000 miles on the factory 4l60E! WTF! Still drives fine other than the pulsing!

Alright, don't want to say to much and brag on it or the fucker will blow up! LOL...

Thanks for the info?
Doesn't bother me too much cause its not my daily driver(it's the wifes!) I would just hate for it to break down some where with the two kids in it...knock on wood! Any other info would be great.:p

you may want to contact a dealer to see if there is a updated flash for the computer, this can help those kinds of problems.

it is a valve in the trans as stated. the bore wears out and causes the problem. Mine had this and it toasted the transmission, before i could get it fixed. There is a sonnax repair sleeve for it. You or the shop will need sonnax 77754-ISO, thats the sleeve, and the reamer for it 77754-RM you will want to triple check those part numbers. Get it fixed before its to late, and while its still cheap.

Thanks for all the help guys. Looks like I need to pull the valve body. :confused: I'll check with my local dealer for parts, cause like I said I would prefer it to be fixed.

How many miles are on the transission?

Mine had about 110,000or 120,000 we I first noicted it. It might be cheaper if it was a higher milage just to rebuild it. They were going to charge me like 150 bucks to fix it they couldn't say it would even fix it. Not to mention the transmission could go out with in the next 20,000 miles.

I dedcided to live with mine and now have almost 200,000 miles on the original 4l60E.

I would weight the cost of repair vs getting the trans rebuilt.

your lucky. mine didn't last the 450 miles home from school. My buddies lasted less than mine. the constant locking and unlocking heats up the trans and it eats itself. When mine was locking and unlocking the temp would jump from its 190 norm to like 220 within a few miles. so 450 miles of that constant toasted it.

your lucky. mine didn't last the 450 miles home from school. My buddies lasted less than mine. the constant locking and unlocking heats up the trans and it eats itself. When mine was locking and unlocking the temp would jump from its 190 norm to like 220 within a few miles. so 450 miles of that constant toasted it. Mine doesn't do it above 50mph and I drive above 55mph so must places so guess it doesn't get hot. Plus I change my fluid and filter regularly.

Mine needs to be rebuilt I am sure its due any day:nuke:! I am hoping it makes it to 200,000!:D