4L80E & TH400 Tech.

[clinebarger]

Originally Posted by softballnrd27

Cline-
I got a 98 model with 80k on the odometer now that is in good working order. I want to just put it in for now, should I go ahead and do the AFL fix now? I want to get it up and running, and start collecting the parts for a proper rebuild. I want to overbuild the transmission to handle 800-900hp but I will probably live in the 6-700 hp area.

If it really only has 80K, You will probably be OK, You can do the AFL fix when you build it. It is usually an issue on higher mileage units, Which most 4L80E's are at this point.

Symptoms of AFL wear are....Wrong gear starts, Converter clutch slip/Fall out Hot, Codes P0757, P0894, P0730.....If it gets bad enough....Clutch Burn-Up.

Originally Posted by 1BadAction

Cline, thanks for this thread, found it google searching for a few things on my 80E valve body rebuild-mod and it's absolute gold.

I have a question re: the AFL bore wear. How can you tell if it's bad? I don't think my 91 has ever been apart other than the fluid and filter I did at 78k. it has 93 on it now.

Do you work at a local DFW transmission shop or are you "retired"?

The above applies to you aswell, But OBD 1 equivalent codes would be 39, 85, 68.

If ya'll want to check the Bore physically, Remove the AFL spring, Move the AFL valve 3/16" from the bottom of the bore & wiggle the valve, Compare that to how much wiggle it has when at the bottom. It is hard to explain "Feel" & "technique"....

I stopped working at Transmission shops long ago, I work at a specialty Performance shop here in Fort Worth, We specialize in TH400/TH350/700R4/4L60E/4L80E performance builds, Ring & Pinion installs, And LSX swaps.

PM me for contact info.

[1BadAction]

Originally Posted by clinebarger

If it really only has 80K, You will probably be OK, You can do the AFL fix when you build it. It is usually an issue on higher mileage units, Which most 4L80E's are at this point.

Symptoms of AFL wear are....Wrong gear starts, Converter clutch slip/Fall out Hot, Codes P0757, P0894, P0730.....If it gets bad enough....Clutch Burn-Up.





The above applies to you aswell, But OBD 1 equivalent codes would be 39, 85, 68.

If ya'll want to check the Bore physically, Remove the AFL spring, Move the AFL valve 3/16" from the bottom of the bore & wiggle the valve, Compare that to how much wiggle it has when at the bottom. It is hard to explain "Feel" & "technique"....

I stopped working at Transmission shops long ago, I work at a specialty Performance shop here in Fort Worth, We specialize in TH400/TH350/700R4/4L60E/4L80E performance builds, Ring & Pinion installs, And LSX swaps.

PM me for contact info.

Cool deal. Right now looking at it through tunerpro I have no pending codes, but that doesn't mean it's not worn. Something has **** the bed in the valve body either way, truck starts in 3rd and slightly binds when pulled into second or OD, rolls down the road and locks the TCC in third as programmed just fine. Best I can figure it's the "B" shift solenoid but I could be wrong, I'll inspect and clean everything. It is going on 26 years old so this is something that just happens. When its out I figured on doing the HD2 shift kit, new TCC, new shift solenoids, new filter screens, torlon check balls, and new 93+ force motor (as transgo instructs in their HD2) along with anything else that might need to be done, including an AFL fix.

Anyhow, if that gets it I'm going to be awesome, if not I'm going to need to get this thing completely gone through. I'll shoot you a PM.