4L80E problems
 

I have a 1996 chevy K2500.The truck sat for about 4-5years due to a spun bearing in motor.I finally got it running but I have no 1st or 4th gear.It starts off in 2nd gear everytime.The previous owner swears there was never a problem with the trans.There was alot of sludge in the pan and the fluid was very dirty.Also does not kick down when you floor it.otherwise it drives and shifts fine back and forth from 2nd to third.Could something be stuck with sludge or something.It is not pulling a trouble code.I was gonna try a flush product and probably pull the valve body apart in the parts cleaner. Any help would be awesome.

Thanks.

RE: 4L80E problems
 

make sure your trans fuse is good...not just visually,make sure its hot on both sides...if there is a power failure,it will default to 2nd

RE: 4L80E problems
 

It sounds like the shift solenoid. Did it throw any codes? If it the solenoid its easy to replace. I get it from the dealer. That was the cheapest place I fond it also I new I was getting the right part. It was like 22.00 or something. This is a quote from 1BADC10 on a different forum hope it helps

1. Pull the main connector, and reseat it firmly.
2. If #1 checks out, make sure the harness is secure & not loose, pinched, etc. (no reason it shouldn't be safe).
3. If the above checks out, drop the pan to make sure the solenoid connectors are firmly fastened. Also check the harness (within the trans) to ensure no wires are cut (can't imagine, but have seen strange things before).

Is it possible that you could have a bad solenoid? Sure. All you'll need then is a replacement. I'd probably replace both, but you can do with one if you're strapped for cash. FYI... the Shift Solenoid A refers to the 1-2 shift solenoid (energized in 1st & 4th). Shift Solenoid B refers to the 2-3 solenoid (energized on 1st & 2nd). What I am wondering is if you actually have first gear. Seems I remember losing the 1-2 shift solenoid rendered 2nd & 3rd gear only. That would give you a fault code for the 1-2 solenoid (A).

Also, make sure the solenoids' resistance measures up to ~40ohms. I remember having to check that when I first started learning about these 4L6xEs. Maybe one of the resident pros & sponsors can clarify this. BTW, Shift Solenoid A is the one on the driver's side. B is the one closest to the passenger side. They are held in place by clips about 1.5 inches apart on the rear side of the valve body. One connector will be orange, the other grey

RE: 4L80E problems
 

Thanks for the info.These sights are great.It did not pull any codes for the trans.My friend borrowed his works snap on scanner($10,000).As we drove the truck the scanner was showing it going through the gears but it physically was not.I will check out the plugs on the trans and the fuse as well.thanks so much for the info.