1234 clutch pack burnt up for a 2nd time.

[smokeydubs]

Alright, I'm humbling myself and asking for help.

I've rebuilt by 6l80 in a 2011 tahoe ppv. Installed sonnax zip kit, sonnax 4-5-6 CLUTCH APPLY PISTON KIT, Transmission Oil Cooler 40,000 GVW, raybestos stage 1 friction, raybestos steels, billet backed torque converter, and have a new techm.



So started out after 1st rebuild that I was having GMLAM issues, after months, finally figured that issue out. Always check plugs and connectors. Lol.

So everything was back together amd you could smell burnt clutches while trying to reach the temp for the relearn. Dropped pan, found clutch material, dropped transmission and found 1234 clutches were toast. Though maybe not enough tranny fluid because I forgot to account for the cooler being about 3X's bigger that the OEM cooler. Only 1234 were burnt, the rest were just as good as when I installed the. I bought new stage 1 clutch pack and steels for 1234. Got everything back together and installed, went to start the relearn process, and I've found that wirh the upgraded cooler, it's a pain in the ass to get the fluid to 160 degrees. So I place in nutrual, hold the brake and set the rpm thru tech2 at about 1600 rpm and watch the temp to start relearn. We'll something didn't seem right, because when I'd take my foot of the brake, while still in nutrual, my wheels would spin as if I was in drive. Confused, I dropped my pan, pulled my valve body and found things as the should be. Reinstalled, added fluid and was having my son hold the break and just shift between P, R, N, D, M and head a bit of a whine,nothing horrendous or enough to make me panic, just wasn't right. Hhmm that's odd. Screw it, decided to pull tranny again(also rear main seal didn't seat right) so got it all apart today and found the 1234 clutch pack burnt up again! So I'm about to torch the whole vehicle, joking. Oddly, the last friction, towards the 35R clutches wasn't burnt up as you can see.



Now the 1st time around I thought it was because, I for some reason, didn't account for the cooler being 3X's larger and thought I had starved them of oil. So this time around I put about 16 quarts of tranny fluid in until it read correct on the dip stick.

So I'm leaning towards a crack in the 1234 piston or bad drum, but all other clutch packs have had no issues, none burnt or anything. Not even the 35R clutches had any issues. Neither time has my tahoe even left the garage, so hasn't even seen the road yet.

So I'm looking for some direction to hopefully fix this issue and not have to remove the tranny for quite awhile! Figure I should damn near be a 6l80 expert since I've torn into it 3 times now. I'm hoping @NickTransmissions can chime in and give some of his expertise because I'm lost.

Shoot me any questions and I'll hopefully be able to respond promptly.

Thanks for your help an input.

Sincerely,

a humbled DIY mechanic

Pics is to this upgrade cooler and how my 1234 clutches look.

 

[NickTransmissions]

Alright, I'm humbling myself and asking for help.

I've rebuilt by 6l80 in a 2011 tahoe ppv. Installed sonnax zip kit, sonnax 4-5-6 CLUTCH APPLY PISTON KIT, Transmission Oil Cooler 40,000 GVW, raybestos stage 1 friction, raybestos steels, billet backed torque converter, and have a new techm.



So started out after 1st rebuild that I was having GMLAM issues, after months, finally figured that issue out. Always check plugs and connectors. Lol.

So everything was back together amd you could smell burnt clutches while trying to reach the temp for the relearn. Dropped pan, found clutch material, dropped transmission and found 1234 clutches were toast. Though maybe not enough tranny fluid because I forgot to account for the cooler being about 3X's bigger that the OEM cooler. Only 1234 were burnt, the rest were just as good as when I installed the. I bought new stage 1 clutch pack and steels for 1234. Got everything back together and installed, went to start the relearn process, and I've found that wirh the upgraded cooler, it's a pain in the ass to get the fluid to 160 degrees. So I place in nutrual, hold the brake and set the rpm thru tech2 at about 1600 rpm and watch the temp to start relearn. We'll something didn't seem right, because when I'd take my foot of the brake, while still in nutrual, my wheels would spin as if I was in drive. Confused, I dropped my pan, pulled my valve body and found things as the should be. Reinstalled, added fluid and was having my son hold the break and just shift between P, R, N, D, M and head a bit of a whine,nothing horrendous or enough to make me panic, just wasn't right. Hhmm that's odd. Screw it, decided to pull tranny again(also rear main seal didn't seat right) so got it all apart today and found the 1234 clutch pack burnt up again! So I'm about to torch the whole vehicle, joking. Oddly, the last friction, towards the 35R clutches wasn't burnt up as you can see.



Now the 1st time around I thought it was because, I for some reason, didn't account for the cooler being 3X's larger and thought I had starved them of oil. So this time around I put about 16 quarts of tranny fluid in until it read correct on the dip stick.

So I'm leaning towards a crack in the 1234 piston or bad drum, but all other clutch packs have had no issues, none burnt or anything. Not even the 35R clutches had any issues. Neither time has my tahoe even left the garage, so hasn't even seen the road yet.

So I'm looking for some direction to hopefully fix this issue and not have to remove the tranny for quite awhile! Figure I should damn near be a 6l80 expert since I've torn into it 3 times now. I'm hoping @NickTransmissions can chime in and give some of his expertise because I'm lost.

Shoot me any questions and I'll hopefully be able to respond promptly.

Thanks for your help an input.

Sincerely,

a humbled DIY mechanic

Pics is to this upgrade cooler and how my 1234 clutches look.

Sucks, man - sorry to hear you're having issues. My questions:

1. Did you air check the 1-2-3-4 clutch (along with all the others) through the pump and when the case was fully assembled?

- If so, what were the results

2. Did you install the Sonnax 1-2-3-4 billet piston?

3. What was/is your 1-2-3-4 clutch clearance?

4. Did you reinforce the welds between the 3-5-R drum's stator and clutch basket?

5. Did you follow the fast relearn instructions to the "T"?

 

[smokeydubs]

Just did the air checks that the book/manual stated doing. Everything seemed as they should and within the callout specs.
I did not install the sonnax 1234 piston. Will be doing do now as well as taking the basket to a local shop the have the actual basket air tested. Did not reinforce welds being it seemed that was a bigger issue prior to 2010.
Followed go a "T" I do believe. Tech 2 says get to temp, then, hold brake if I remember right. Been about 1.5wks since that was attempted.

 

[smokeydubs]

Also, would i use the 8th check ball and the updated seperater plate even though it didn't come oem that way? Would that mess a thing up at all?

 

[Just Fishing]

did you replace the 1234 drum?
Usually that drum cracks and you can't see it, or it's that piston.

was this the original failure for the transmission as well?

 

[smokeydubs]

---

Found the culprits... Didn't inspect the 1234 piston well enough, and I'd say the broken ring and punch ring didn't help the situation at All.

 

[petethepug]

Oh, that’s not fun.

 

[NickTransmissions]

Just did the air checks that the book/manual stated doing. Everything seemed as they should and within the callout specs.
I did not install the sonnax 1234 piston. Will be doing do now as well as taking the basket to a local shop the have the actual basket air tested. Did not reinforce welds being it seemed that was a bigger issue prior to 2010.
Followed go a "T" I do believe. Tech 2 says get to temp, then, hold brake if I remember right. Been about 1.5wks since that was attempted.

Always weld the 3-5-R drum. They all leak, it's just not as bad post 2010. But that's the transmission equivalent to saying getting shot in the leg is not as bad as getting shot in the face so i dont seek medical attention when i get shot in the leg.

---

Found the culprits... Didn't inspect the 1234 piston well enough, and I'd say the broken ring and punch ring didn't help the situation at All.

Glad you found it - would have been much more stressful not to have a clear smoking gun to explain the problem.