6L80E Junk Transmissions

dna9656 · March 20, 2024

So my brand new to me 2015 Silverado with 136 k miles has a "Getting hit by a hammer" sensation when under load, going up hill, or on the flat road. It's intermittent, but is happening more often. I think it's that piece of crap torque converter grenading it self, but I'm no tranny guy. I know one, the best in town, he won't work on them; too much trouble. He upgraded my '06 Avalanche from the crappy 4l60 E to a corrected 4l 70E, no problems with that tranny, my ex bought the truck from me and has had no issues. I totally get a tranny wearing out, they do usually from neglect, no one changes the fluid or the filter; they burn up cause the fluid no longer does it's job, THAT'S on the people that don't do maintenance; fault engineering isn't on the people, it's on GM. Can some confirm my TC is going to crap?

EDIT: Now I have a shudder with that wham, wham, wham the truck does when up a hill or under load. I just changed the fluid and filter, cut the pressure cooler line, clamps a 3/8" rubber hos to it the hose is 5' long, pointed the hose to a bucket, filled the tranny pan and started the truck up. What came out of the hose as new fluid was poured in wouldn't pass for tranny fluid, more like some one put motor oil in it. It was was too viscus when cold to be tranny fluid. I'm hoping the cleaning properties of tranny fluid will clean up any varnishing. The trans seems to (otherwise) operate normally. I follow the Manual, it says to use AC Delco DEXRON VI, (in the tranny and the Xfer case) it does not say it's ok to use an equivalent. The book also says to use GM Dexos Standard 1 synthetic blend motor oil in the engine "or equivalent". So it's ok to use "equivalents" in the engine but no where else.

Edited April 2, 2024 by dna9656
Spelling, punctuation

newdude · March 20, 2024

1 hour ago, dna9656 said:

So my brand new to me 2015 Silverado with 136 k miles has a "Getting hit by a hammer" sensation when under load, going up hill, or on the flat road. It's intermittent, but is happening more often. I think it's that piece of crap torque converted grenading it self, but I'm no tranny guy. I know one, the best in town, he won't work on them too much trouble, he upgraded my '06 avalanche from the crappy 4l60 E to a corrected 4l 70E, no problems with that tranny, my ex bought from me and has had no issues. I totally get a tranny wearing out, they do usually from neglect, no one changes the fluid or the filter; they burn up cause the fluid no longer does it's job, THAT'S on the people that don't do maintenance. fault engineering isn't on the people, it's on GM. Can some confirm my TC is going to crap?

Yes. And its likely damaging the fluid pump and the 4-5-6 clutch set is probably smoked as well.

Edited March 20, 2024 by newdude

mikeyk101 · March 20, 2024

My 2016 just went out on me at 96k miles. I didn't have any of the symptoms you are having. Mine gave no warning at all. One minute driving along fine and next minute I was slowing down and accelerator did nothing to increase speed.

Unfortunately I didn't get the actual cause of the problem, I just know that they found metal shavings in pan and dark fluid. A replacement trans was the only solution. I had done a fluid replacement at 49k miles and was planning on doing the next one when getting my next oil change. I believe they call for fluid change every 50k miles. At least now I don't have to pay for the next trans fluid replacement, LOL!

dna9656 · March 20, 2024

Chances are your TC started breaking down, they friction weld the 2 halves together and that isn't working out, also they weld the bolt pads for the flywheel/CT connection, the casing for the TC is low grade metal, it doesn't take the welding of the pads and the metal won't flex so it breaks, the piece from the friction weld and the bit of metal from the cracking welds holding the pads make there way into your tranny. if you have a GM TC chances are good you have another tranny in your future.

mikeyk101 · March 20, 2024

57 minutes ago, dna9656 said:

if you have a GM TC chances are good you have another tranny in your future.

Yes, I'm sure it's a GM torque converter because it's a GM Reman tranny. On the plus side, it has a 3 year 100,000 warranty. I have seen some other threads about decent aftermarket torque converter but they seem a bit pricy although it seems reasonably so. I think my plan is to leave it alone for now but if it doesn't fail before warranty is up, change out the TC prior to that with an upgraded one.

PFTX_5.3 · March 20, 2024

1 hour ago, dna9656 said:

if you have a GM TC chances are good you have another tranny in your future.

They're very hit-and-miss. 250k+ on some of ours and 80k on one

Edited March 20, 2024 by PFTX_5.3

dna9656 · March 21, 2024

Anyone have any experience with https://nextgendiesel.com/ and their next gen drive train page? Anyone buy from them or have a warranty claim? if so how did it go for you? These guys want $7,500 plus shipping and you have to get the internal computer programmed at a GM dealer. They offer a 2 year complicated warranty.

Same questions for https://reman-transmission.com/ 5 year, unlimited mileage, parts and labor. $2441.00

Quite a price disparity huh?

The only shop in my area wants $8 grand for a tranny and I have no idea what the warranty is; hoping it's more than just a kiss or a reach around.

....

Edited March 22, 2024 by dna9656

dna9656 · April 17, 2024

Turns out I had a misfire on #4 cylinder, put the spark plug wire back on the plug and all symptoms have disappeared.

dna9656 · May 13, 2024

Got succked in. Guy with 5 stars on Y something or other told me $3K, for his labor plus $ for part sand he had coupons on site he would give me. OK, rebuild it with GOOD parts. $8 ucking thousand dollars to rebuild the 6L80. 3 days later I get a "Engine power reduced" message from the info center in that dash. I never did see those coupons mentioned on the bill. I did get a reman billet converter, he replaced the rear main seal and a exhaust clamp. I was under the truck and there are signs the truck was actually worked on, I pulled the insp. patch on the bell housing, that converted sure is clean and has a conventional (machine weld on the middle of the converter) No wet motor oil from a leaky RMS. What sucks is I have seen rebuilt trannys on line with 5 year warranties for under $2k. I got 12 months 12k miles. I told the guy I wanted Dextron 6 in the tranny, I got "world class" fluid. I am not a happy camper. I have to decide if I am going to change the fluid or not, I mean if i do will it void the warranty, such as it is? The GM book say use dex 6 PERIOD; right above that it says you can use any motor oil in the engine you want so long as it meets blah, blah, blah. No such latitude is allowed for the tranny fluid. Parked the truck, go to church in the Nissan. Got home, pulled codes, only new code is (can't rem the code) gas pedal voltage wrong, something like that. Book says to check the routing of the wiring, so I go out there, start nosing around the wires where the engine temp sensor throttle body is, the black plastic tube GM puts the wiring into, I squeeze it and it turns to dust! Holy Feces Batman! I have some on hand. I bought a "top side creeper" from TEMU.com. Don't buy it, it's a POS. I went to return it and they said I could keep it, that's what I wanted to say to them. I bought a much nicer one on Amazon. You should look into it. If you buy one you will want to find some cushioning material to protect the paint work on your truck from the ladder section of the creeper. Does anyone know of a good Catalytic converter Y pipe I van buy that is of OEM quality but doesn't have the crazy OEM price?

Edited May 13, 2024 by dna9656