Transmission options

Chevyfan3 · March 22, 2023

What's everyone doing to resolve transmission issues with there 6l90e? I have lost 5-6 gear with a po741 recently with 49k miles. Fluid looks great and no burnt smell from what I see on the dipstick. I haul a 7500lb travel trailer so maybe I'm overloading this rig. I had a 17' tundra 5.7 before this truck that I went 60k with and no issues. Thought upgrading to an HD was the smart move for long term hauling reliability. So my options seem to be dump the truck and go back to Toyota, get a GM reman $5500 and have the 3yr nationwide warranty but they won't let me install a better converter with that (so I'll just be getting the same crap and waiting for it to fail again) or try to find a local trans shop in my area and hope for the best. Crushing blow and support disappointed in this, fluid has been changed every 10k after camping season and I'm still left with a failure. I travel far with this truck 1200-1400 miles so I need it to be reliable.

diyer2 · March 22, 2023

I feel your pain.

Roll the dice with a custom built trans towing 7500 lbs.

Chevyfan3 · March 22, 2023

Just now, diyer2 said:

I feel your pain.

Roll the dice with a custom built trans towing 7500 lbs.

You think I'm pulling to much for the 6l90 and 6.0? Should I just go ahead and upgrade to a dmax? I'm afraid I'm gonna spend this money just to have it fail again.

diyer2 · March 22, 2023

Daily driver?

7500 lb travel trailer is occasional use right.

Not worth the up front cost and maintenance of a diesel to me.

But if you want longevity diesel with Allison trans.

KARNUT · March 22, 2023

In the good old days you could daily drive a diesel. My 83 year old mother has been driving a 2000 Ford 1 ton 7.3. It just passed 200K miles with very little maintenance. She drives secondary roads barely hitting 60. It’s an amazing vehicle. Her other diesel is a 98 Ram 3/4 ton diesel. It was my father’s last work truck retiring in 2000. It has about the same mileage.

newdude · March 22, 2023

4 hours ago, Chevyfan3 said:

What's everyone doing to resolve transmission issues with there 6l90e? I have lost 5-6 gear with a po741 recently with 49k miles. Fluid looks great and no burnt smell from what I see on the dipstick. I haul a 7500lb travel trailer so maybe I'm overloading this rig. I had a 17' tundra 5.7 before this truck that I went 60k with and no issues. Thought upgrading to an HD was the smart move for long term hauling reliability. So my options seem to be dump the truck and go back to Toyota, get a GM reman $5500 and have the 3yr nationwide warranty but they won't let me install a better converter with that (so I'll just be getting the same crap and waiting for it to fail again) or try to find a local trans shop in my area and hope for the best. Crushing blow and support disappointed in this, fluid has been changed every 10k after camping season and I'm still left with a failure. I travel far with this truck 1200-1400 miles so I need it to be reliable.

Have a shop do it. You can upgrade the converter and the 4-5-6 clutches during the build as many transmission companies have upgrades for those both. A Gm reman will be all new and have that nice warranty but they don't use a revised/billet converter nor do they add upgraded 4-5-6 clutches.

No, 7500lbs is not excessive for a 2500hd, and definitely not excessive for a rebuilt and upgraded 6L90. You aren't overloaded at 7500lbs for a truck that's rated for over 13,000lbs.

Unfortunately there is just some sort of issue in the design or manufacturing chain GM ran into on these 6L80 and 6L90 transmissions some time after they started the 2015 generation launch on HD and 2014 on 1/2 tons. Prior to this, there was a much lower failure rate. 07-13 trucks we almost never pulled out a 6L80 or 6L90 for issues.

Edited March 22, 2023 by newdude

Chevyfan3 · March 22, 2023

1 hour ago, diyer2 said:

Daily driver?

7500 lb travel trailer is occasional use right.

Not worth the up front cost and maintenance of a diesel to me.

But if you want longevity diesel with Allison trans.

No not a daily I use this for camping trips with the family 1-2 times a month with an average trip of 1200 miles. That's why my milage is so low. It's a personal truck, not beat on at all.

I hear ya, I looked at diesels and it's a 10k up charge , whew.

Chevyfan3 · March 22, 2023

37 minutes ago, newdude said:

Have a shop do it. You can upgrade the converter and the 4-5-6 clutches during the build as many transmission companies have upgrades for those both. A Gm reman will be all new and have that nice warranty but they don't use a revised/billet converter nor do they add upgraded 4-5-6 clutches.

No, 7500lbs is not excessive for a 2500hd, and definitely not excessive for a rebuilt and upgraded 6L90. You aren't overloaded at 7500lbs for a truck that's rated for over 13,000lbs.

Unfortunately there is just some sort of issue in the design or manufacturing chain GM ran into on these 6L80 and 6L90 transmissions some time after they started the 2015 generation launch on HD and 2014 on 1/2 tons. Prior to this, there was a much lower failure rate. 07-13 trucks we almost never pulled out a 6L80 or 6L90 for issues.

Yeah a local shop quoted me 4500-7500 said it just depends how bad it is once it's apart. I figured I wasn't pushing this truck to bad, it's been great until this major failure. I just need it to be reliable so I don't get stuck traveling somewhere with my family and camper.

I thought the 6l90 was pretty bulletproof, so it's the earlier years. You would think gm would offer some kind of fix for this for customers. My dad had a 10 year old Saturn Vue that they 100% covered for to a special campaign of the wave plate I think. Such low mileage trucks going out can't be a good look for GM.

Chevyfan3 · March 22, 2023

Well called a bunch of the higher rated transmission shops in my area and no one builds 6l90's they all told me they just get gm remans and slap them in there. Said the cost to build one puts you over the reman cost so it doesn't make sense for them. If I add a better convertor to the GM reman no warranty. So I'm going to put $5500 into it and end up with the same ole garbage, nice. I had a feeling I would run into that, my area sucks for machine shops, custom vehicle shops.

diyer2 · March 23, 2023

A suggestion, switch the new trans to Amsoil fluid.

64BAwagon · March 23, 2023

The converters are the main weak link on these transmissions. Unless you could upgrade to a billet torque converter on the new one I think youre just throwing good money after bad.

Without a tear down on the old one theres really no way to know for sure what failed.

That setup should have easily handled 7500lb

Chevyfan3 · March 24, 2023

22 hours ago, 64BAwagon said:

The converters are the main weak link on these transmissions. Unless you could upgrade to a billet torque converter on the new one I think youre just throwing good money after bad.

Without a tear down on the old one theres really no way to know for sure what failed.

That setup should have easily handled 7500lb

I agree totally, it at the very least needs a bullet convertor. Issue is the shops around me won't rebuild these units and just install gm remans which won't allow me to upgrade it and keep the warranty. So I'm stuck.

Fluidwise it was always changed everyear after camping season, used the Delco fluid and it always looked great. I doubt going to another fluid would of changed my outcome.

I think I'm just going to trade the truck off, been a long time Chevy truck owner but maybe it's time to try something else. If I get a newer hd they still have the 6l90e and if I wait for a 2024 I'm going to miss a good chunk of my camping season.

64BAwagon · March 24, 2023

33 minutes ago, Chevyfan3 said:

I agree totally, it at the very least needs a bullet convertor. Issue is the shops around me won't rebuild these units and just install gm remans which won't allow me to upgrade it and keep the warranty. So I'm stuck.

Fluidwise it was always changed everyear after camping season, used the Delco fluid and it always looked great. I doubt going to another fluid would of changed my outcome.

I think I'm just going to trade the truck off, been a long time Chevy truck owner but maybe it's time to try something else. If I get a newer hd they still have the 6l90e and if I wait for a 2024 I'm going to miss a good chunk of my camping season.

The trucks with the 6.6 gas have a different 6L90 than previous trucks with the 6.0 had. They made some improvements to them including an extra clutch.