4L80 Lost 4th, 3rd, and Reverse. Can I fix it ?
Thread Starter
TECH Fanatic
Joined: Jul 2022
Posts: 1,036
Likes: 390
From: Alaska
4L80 Lost 4th, 3rd, and Reverse. Can I fix it ? Greetings all Trans Experts:
Before installing TURBOcharger on my half ton Suburban, I stuffed a "Low Miles" GM Goodwrench Reman 4L80 in, shortened driveshaft, extra cooler, CircleD Torque converter. Was having lotsa fun tuning, finally got all my fuelling and timing tables dialed in safe. Turned wastegate DOWN to 12 PSI on spring, was daily driving....... and then had 4th gear and then 3rd gear SLIP.
Barely have reverse, it "gently clunks" in gear, but any throttle and it just slips.
In D or 3 positions, I get no -Go engine revs freely, if I select manual first or Second I can give it power, and get full converter stall (2800rpm)
Trans needs to come out, and I want to try to LEARN how to disassemble, diagnose and fix. I have plenty of time, it's a project vehicle.
.
I see several vendors on Ebay " acerl" and 'transdeal4U' that sell various parts and O/H kits.. cheap basic kits from 300 on up.
Key words "ALTO RED Level 2" is in the $600 range. Is this a good set of parts to start with for around 600 Flywheel horsepower in a 6000 pound vehicle ?
Next: any vendors to avoid, or some that come recommended ?
Is it possible from my exact symptoms that I just ripped up ONE SINGLE part, ie forward sprag, or something simple ?
I can say for certain that it never got anywhere near hot, the fluid was ALWAYS kept one quart above the fill line, and is still clean, just like it came out of the bottle..
Any advice, tips, tricks, vendors or parts to AVOID, or good parts sources, information resources: Please advise.
Thanks for the help.
Before installing TURBOcharger on my half ton Suburban, I stuffed a "Low Miles" GM Goodwrench Reman 4L80 in, shortened driveshaft, extra cooler, CircleD Torque converter. Was having lotsa fun tuning, finally got all my fuelling and timing tables dialed in safe. Turned wastegate DOWN to 12 PSI on spring, was daily driving....... and then had 4th gear and then 3rd gear SLIP.
Barely have reverse, it "gently clunks" in gear, but any throttle and it just slips.
In D or 3 positions, I get no -Go engine revs freely, if I select manual first or Second I can give it power, and get full converter stall (2800rpm)
Trans needs to come out, and I want to try to LEARN how to disassemble, diagnose and fix. I have plenty of time, it's a project vehicle.
.
I see several vendors on Ebay " acerl" and 'transdeal4U' that sell various parts and O/H kits.. cheap basic kits from 300 on up.
Key words "ALTO RED Level 2" is in the $600 range. Is this a good set of parts to start with for around 600 Flywheel horsepower in a 6000 pound vehicle ?
Next: any vendors to avoid, or some that come recommended ?
Is it possible from my exact symptoms that I just ripped up ONE SINGLE part, ie forward sprag, or something simple ?
I can say for certain that it never got anywhere near hot, the fluid was ALWAYS kept one quart above the fill line, and is still clean, just like it came out of the bottle..
Any advice, tips, tricks, vendors or parts to AVOID, or good parts sources, information resources: Please advise.
Thanks for the help.
Thread Starter
TECH Fanatic
Joined: Jul 2022
Posts: 1,036
Likes: 390
From: Alaska
If I caught it EARLY, as in: only had rpm flare 3 times before I parked it ... Is there Any chance I did not tear up a bunch of nearby parts ?
Is there an upgrade HD sprag that will retro-fit without a buncha machine work ?
Is there an upgrade HD sprag that will retro-fit without a buncha machine work ?
