4L80E jumping in and out of OD

[Jbarry14]

I have a 1996 Chevy K3500 5.7l with the 4L80E trans

Recently my truck has been having problems shifting at the correct times and sometimes it shifts a little hard. Now when I get to around 50mph it jumps in and out of OD or lockup constantly. The truck has low power, which I am assuming is from the dirty injector. I am thinking it is possible it could have something to do with the TPS, but I have no codes for that. The only code I have is for my bank 2 being lean from a dirty injector. I will be replacing the injectors soon, But I would really like to solve this transmission problem.

Thanks in advance!

 

[RichLo]

Fix one problem at a time. If you know you have a dirty injector, ultrasonic clean them and flow test ALL of them. Dont just replace 1, they all have to be balanced corectly.

There are options out there for anywhere between $20-$35 per injector. I have not advertised on here but I also now do this for a local auto parts store in my free time, if you want I am cheaper. I can take pictures, videos, and give you a flowed spreadsheet before and after cleaning. If not me, look for somebody who at least offers detailed numbers rather than just pass/fail.

 

[Jbarry14]

Yes, I am going to replacing the injectors with new spider injectors. But I would like to know if the transmission is acting like this because of something electrical or something internal.

 

[ima93chevyguy]

Check brake light switch. That's the most common and easiest thing that'll make it do that.
Sometimes you can use your foot and pull up on the brake pedal and it'll stop

 

[Schurkey]

it jumps in and out of OD or lockup constantly.

WHICH?

Torque converter clutch lockup would be more likely.

 

[HotWheelsBurban]

Isn't there an RPM range that the TC locks up, and below that it's unlocked? And refresh my memory, which is better for towing?

 

[Jbarry14]

WHICH?

Torque converter clutch lockup would be more likely.

I would assume its the TC. Its not a hard shift. Just the RPMs jump around and it constantly locks and unlocks above 50MPH. But the transmission also shifts through all of the gears at the wrong time. Sometimes they are hard shifts too.

 

[Jbarry14]

Check brake light switch. That's the most common and easiest thing that'll make it do that.
Sometimes you can use your foot and pull up on the brake pedal and it'll stop

I will test that. Thanks

 

[BeXtreme]

A vacuum leak would cause both the lean bank code and the issues with lockup/shifting. Check the intake manifold gaskets and vacuum hoses for leaks.

 

[Jbarry14]

A vacuum leak would cause both the lean bank code and the issues with lockup/shifting. Check the intake manifold gaskets and vacuum hoses for leaks.

I actually had it fog tested. No vacuum leaks. Went through everything when trying to figure out the lean code.