Hello,

Just wondering if anyone has any experience with issues on the 4l80E. My truck is a 2002 H1 with the 4l80E. I took it out for a drive today and everything was fine except that it wouldn't go into overdrive. I just maintained a lower cruising speed to keep the RPMs and fuel drinkage down.

Here are some notes:
●good shifting into reverse
●no codes
●good solid shift from 2-3
●that I could see on a Scanguage3, the trans was not overheating.


I'm going to try replacing the fluid, which I was going to do anyway, and see if that helps. Anyone with other advice?


Update: after wrestling with the crossmember to remove it, I changed the fluid and filter. After test driving I found that this didn't improve the situation, and then I finally pulled a P1870 code. I had a local trans rebuilder check it with his scantool to record the TCC action and he determined that it's most likely a bad torque converter. And if I'm going to do that, I might as well do a rebuild. Just wasn't expecting this at 76K miles.

 

What color is the fluid? I recommend Seafoam trans tune to remove all the varnish buildup, if dark include a flush & filter change.

 

Also, possible bad OD/Converter lockup solenoid or converter lockup mechanism failure, also possible lockup temperature sensor bad. Time to grab your Tech 2 and do some tests!

 

Thanks for the advice. After deciding to do a filter and fluid change, and a grueling day of trying to get the crossmember out, and even worse-back in, here is where I am:

● completed trans service with filter
●fluid was dirty but not burnt
● only a little fine grey goo/metal on the magnet
● put in 4 qts DEX- III level seemed good
●Drove around town and 1,2,3 gears working fine.
●stopped and checked level and it seemed low (was showing a little below the hot area)
● when I got on the interstate to test out the OD, the truck seemed like it had shifted into 4, and was I running 65 MPH @ 2600 RPM
●about 2 minutes later with light pressure on the pedal on only a slight uphill @65 MPH it all a sudden went from 2600 RPM to around 3000.
●I stopped and checked the fluid level again and at that point it seemed too high
●don't have a Tech II, so I had it scanned and there are no trans codes