You Chevy guys xan help me.
little problem I cwant pin point.

1999 Chevy half ton 4.8 auto

the tranny shifts like crap, it could be worse, it's just not 100%, maybe closer to 75%, anyways, slight rough shifts( always a little clunk into gears, all dem ), going from p to r, or p to d, ETC, is always a 2-3 sec delay_ not normal to say the least. SMASHES into second if in over drive/ tow haul. And The Speedo and tach are not perfectly steady, they bounce around say 1-3 mph and 1-300 rpm, worse when on rough roads. Abs light on , I ASSUME these are all related. Maybe t case issue.. No codes.

I personally assume this is a speed sensor, electrical issue, but I'm not sure where to look. This weekend, or when ever I ger ttime I am bringing it to a transmission shop to check for codes that font throw a cel. Tranny fluid was swapped 3 years ago.

Ideas? Sorry if I bore you with non brz threads, srs issue. Tks

This post was edited by IB0T on Aug 20 2014 07:07pm

is it a 4le60 or 80? probably a 60 but i have to ask..

check the fluid?

No idea, regular half ton, so probably the lighter trans, fluid good and pink smells nice.

It's a 4L60E. How many miles are on it? The trans is the weak link in these trucks. Expect it to need a rebuild between 140k and 200k depending on how it is used.

this my buddy owns a trans shop and hes always rebuilding them fixing to do my work truck

210
but at a glance under there, it looks like it's been opened before. I see dem ultra Cooper hanging flaps everywhere.
I'm not too rough on it, I use this truck almost every weekend to do my shit, and I'm not afraid to get on it, other than a a slightly lazy tranny it's smooth.
I just can't shake the feeling it's a electrical or sensor problem since I bought ir

Probably the valve body. Pressure is probably out of wack. Bah, I'll see if a ttransmission shop can pull any codes, if not ride till
die. Fix after

The clunk going into gear could be attributed to u-joints or the rear end has a ton of play possibly.

As far as the transmission like others said take it to a shop and have them pull codes. Could be something stupid like a speed sensor or it could need to be rebuilt. Really hard to tell without looking at it but judging by the mileage it wouldn't hurt to have it freshened up.

If I were you I would get the code read and replace whatever is bad with that and if that doesn't fix it I'd go with changing the transmission fluid and adding Lucas transmission slip fix. That shit works miracles.

I won't put that shit in anything. Once it starts to slip it's done. Adjusting the bands is the real band aid if they are adjustable. If that is done and it starts to slip again it's time for a rebuild. Everything I've seen the Lucas stuff or any other slip fix go in has lasted 1 more oil change or so and shit itself.