Suddenly lost 4th gear 4L80E
I see it broken in the pictures you posted.
A "pressure plate" is the common term used for the end plate used to hold the clutch pack in place. The clutch is applied by the piston, and pressure from the pack is held by the "pressure plate".
I don't know what the specific verbage used by the manual you are using calls it. I haven't used a manual to build a 4L80E in quite a few years.
The iron piece that is broken off, came off the pressure plate. It is a "tang" that fits into the OD housing and then also the case to keep things from spinning and putting pressure on the bolt (that is broken).
Look at the parts closer and you will see the cause and effect.
A "pressure plate" is the common term used for the end plate used to hold the clutch pack in place. The clutch is applied by the piston, and pressure from the pack is held by the "pressure plate".
I don't know what the specific verbage used by the manual you are using calls it. I haven't used a manual to build a 4L80E in quite a few years.
The iron piece that is broken off, came off the pressure plate. It is a "tang" that fits into the OD housing and then also the case to keep things from spinning and putting pressure on the bolt (that is broken).
Look at the parts closer and you will see the cause and effect.
It's the tab I circled with red, correct?
Couple of OD clutches pics. Look pretty much new except frontmost clutch which has slight wear mark.
Frontmost clutch is .0795 thick and other 3 are .0815 thick.
Should I replace them?
Should I check anything else that can be easily checked while tranny is half-apart?
Frontmost clutch is .0795 thick and other 3 are .0815 thick.
Should I replace them?
Should I check anything else that can be easily checked while tranny is half-apart?
Clutches don't look too terrible.
The only scenario I can really picture causing this was a huge pressure spike in 4th engaged the clutches hard enough to crack the pressure plate. If the force is strong enough to crack the pressure plate, it'd definitely be strong enough to break push the basket enough to break the bolt.
Without knowing what your pressure look like in each gear, it's hard to say. Might not hurt to crack open the pump and check the valves. Check for wear on the pump surface as well.
The only scenario I can really picture causing this was a huge pressure spike in 4th engaged the clutches hard enough to crack the pressure plate. If the force is strong enough to crack the pressure plate, it'd definitely be strong enough to break push the basket enough to break the bolt.
Without knowing what your pressure look like in each gear, it's hard to say. Might not hurt to crack open the pump and check the valves. Check for wear on the pump surface as well.
Actually looking closely at that broken tab of pressure plate, I can't see it holding OD assembly against case because tab is only 1/2" wide, while in the tranny case this is much wider (post #41 also shows that)
Try not to over think it and just take our word for it bro. It gives it a little bit of play, and the pressure plate tab is not as wide as the indentation for it in the case. Totally normal.
If it doesn't fit tightly into recession in the case, then the only thing that stops assembly from rotating even .05" is feed bolt. I must be getting smth. wrong then. LS1 Tech Stories
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FormerVendor
Joined: Apr 2014
Posts: 263
Likes: 2
From: Justin, TX
Having hard time finding 4L80E torque specs, what are torque specs for feed bolt, valve body bolts and pump bolts?
edit: found 18lbs for pump bolts and 17-19lbs for feed bolt
edit: found 18lbs for pump bolts and 17-19lbs for feed bolt
Last edited by Vetal; May 22, 2014 at 06:53 PM.
If you need them, I can/will e-mail a couple of manuals...I rebuilt mine with them. Send me a PM if you need them.
I wonder why if I try to turn splined shaft of oil pump, it doesn't move? Is that how it's supposed to be? 
P.S. Damn new feed bolt broke when I was just trying to tighten it to 19lbs. Damn. I'll have to invent something tomorrow...
P.S. Damn new feed bolt broke when I was just trying to tighten it to 19lbs. Damn. I'll have to invent something tomorrow...
I had to make my own feed bolt, hope it's function is as simple as I see it and it will do fine.
Guys is this normal that pump shaft does not rotate at all?
Also, 2 of the pump bolts somehow did not have rubber grommets on them, so now I either have to put them on silicone on top (so they are not submerged in oil), or place them at the bottom so later I can replace them with converter in place (if this is possible at all)
Guys is this normal that pump shaft does not rotate at all?
Also, 2 of the pump bolts somehow did not have rubber grommets on them, so now I either have to put them on silicone on top (so they are not submerged in oil), or place them at the bottom so later I can replace them with converter in place (if this is possible at all)
Attached is a good Stock 4L80E manual with flow charts. It's been floating around on the net for some time. 
Awhile back someone took 1 apart and did a write up.
Right now this is all I could find.
http://www.performancetrucks.net/for...thread-396429/
Awhile back someone took 1 apart and did a write up.
Right now this is all I could find.
http://www.performancetrucks.net/for...thread-396429/
Attached is a good Stock 4L80E manual with flow charts. It's been floating around on the net for some time.
Awhile back someone took 1 apart and did a write up.
Right now this is all I could find.
http://www.performancetrucks.net/for...thread-396429/
Awhile back someone took 1 apart and did a write up.
Right now this is all I could find.
http://www.performancetrucks.net/for...thread-396429/
Good write up!
Thanks for your help!
My apologies. It looks like it's too large to upload to the site.
Get it from this thread---> http://www.performancetrucks.net/for...al-pdf-519818/
Get it from this thread---> http://www.performancetrucks.net/for...al-pdf-519818/