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I'm tearing down my 4L80E to rebuild and it looks like the forward drum assembly got really hot. Is this a concern? Should I replace these parts since they got hot?
I'll check the lands for damage and I plan on replacing the steels and frictions but do I need to worry about the drum, direct and forward hubs being damaged due to the heat? Can these parts warp or weaken due to excessive heat?
Check that the area where the teflon rings ride is still smooth if not they will leak also make sure all the teflon rings on the input shaft are good along with of course the seals and piston in the forward clutch.
I'll check the lands for damage and I plan on replacing the steels and frictions but do I need to worry about the drum, direct and forward hubs being damaged due to the heat? Can these parts warp or weaken due to excessive heat?
Thanks!
S.F.
I bet the discoloring is from friction material, Take a razor blade & see if the black stuff scraps off, High Energy frictions make a mess when they burn up!
If the Input Shaft didn't damage the drum.....Don't worry! When there real bad I media blast them (Cover the Checkball in the Drum with tape or just be careful not to blast it) Then clean the drum real well, Watch for friction material build up around the Checkball.
I bet the discoloring is from friction material, Take a razor blade & see if the black stuff scraps off, High Energy frictions make a mess when they burn up!
If the Input Shaft didn't damage the drum.....Don't worry! When there real bad I media blast them (Cover the Checkball in the Drum with tape or just be careful not to blast it) Then clean the drum real well, Watch for friction material build up around the Checkball.
Good stuff, thank you sir! I'll check it out and report back.
I bet the discoloring is from friction material, Take a razor blade & see if the black stuff scraps off, High Energy frictions make a mess when they burn up!
If the Input Shaft didn't damage the drum.....Don't worry! When there real bad I media blast them (Cover the Checkball in the Drum with tape or just be careful not to blast it) Then clean the drum real well, Watch for friction material build up around the Checkball.
Well, when scraped with a razor blade the discoloration lightens just a tad but is still pretty significant. The bushing that rides on the input shaft looks like it has significant wear and there are marks on the shaft but I can't hang a fingernail on it. I "think" some steel wool or fine scotchbrite should shine it up. The overall black color of the forward and the blueing on the hub where the planetaries ride is what has me most concerned. Of course I haven't taken it apart yet so it could be trashed inside of all the friction material is gone and the steel backing was grinding away on things....
This is the part where I wish I could get the eyes of a professional on the hard parts.
I am no professional transmission builder, but I can tell you that the 500 -1400 F temperature required to anneal any larger part like a shaft or drum would be very difficult to do, some parts inside are flame hardened, that may be the cause of the blue you are seeing. The steel plates slipping against friction discs can get that hot because they are very thin and don't have much mass.
Side note: I have never used them, but perhaps sonnax 34716-01 may be a good idea for your transmission, the photos make it look like the forward drum has wear grooves that should be cleaned up.
I am no professional transmission builder, but I can tell you that the 500 -1400 F temperature required to anneal any larger part like a shaft or drum would be very difficult to do, some parts inside are flame hardened, that may be the cause of the blue you are seeing. The steel plates slipping against friction discs can get that hot because they are very thin and don't have much mass.
Side note: I have never used them, but perhaps sonnax 34716-01 may be a good idea for your transmission, the photos make it look like the forward drum has wear grooves that should be cleaned up.
That's good eyes! I inspected the forward drum closer today and it is good thing I did as it is indeed grooved. Looks like a common problem and there are numerous methods of repair like the Sonnax kit, Omega machine's repair sleeve and bushing kit / service, etc... Right now I'm looking at buying a replacement drum. Haven't decided on
New, Used or reman yet...
No friction material left in the forward clutch!
The direct hub looks ok though..
S.F.
Last edited by StolenFox; Jun 29, 2016 at 10:28 PM.
Reason: Notes for pics
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4L80E experts: overheated forward drum 
