Upgrade transmission recommendations?

[Wylie_Tahoe]

While doing some recon when my trans bit the dust, I saw a couple references to the 4L65 as being a more robust 4L60. I did not go this route as I wanted more definitive info on the subject, but time was not on my side.

 

[HiHoeSilver]

While doing some recon when my trans bit the dust, I saw a couple references to the 4L65 as being a more robust 4L60. I did not go this route as I wanted more definitive info on the subject, but time was not on my side.

Main difference is 4 vs 5 gear planetary. The 65 may have an upgraded sunshell. Not 100% sure on that one.

 

[swathdiver]

...looking for your recommendations for a good, reasonably priced upgraded transmission and torque converter.

Main difference is 4 vs 5 gear planetary. The 65 may have an upgraded sunshell. Not 100% sure on that one.

GM put the 4L70 behind the 366 horsepower L76 6.0 motors in pickups and maybe some Suburbans/Yukon XLs. Most, if not all of the SUVs with the L76 got the 6L80. You can build yours to a similar standard or just get a 4L70. GM Performance also offered a 4L75, even more stout but probably not necessary for your application.

4L60 = M30
4L65 = M32
4L70 = M70
4L80 = MT1
4L85 = MN8

 

[Sam Harris]

GM put the 4L70 behind the 366 horsepower L76 6.0 motors in pickups and maybe some Suburbans/Yukon XLs. Most, if not all of the SUVs with the L76 got the 6L80. You can build yours to a similar standard or just get a 4L70. GM Performance also offered a 4L75, even more stout but probably not necessary for your application.

4L60 = M30
4L65 = M32
4L70 = M70
4L80 = MT1
4L85 = MN8

4L70 seems like a great option, and wouldn’t be much more than 4L60. What would I need to convert to this..? Is it a drop in? Any programming required, or adapters, etc..?

 

[swathdiver]

4L70 seems like a great option, and wouldn’t be much more than 4L60. What would I need to convert to this..? Is it a drop in? Any programming required, or adapters, etc..?

Sorry, I do not know Sam. Check over at Performance Trucks forum. Lots of good info just googling 4L70E on the first page.

https://www.chevrolet.com/performance/transmissions/supermatic-4l70-e/two-wheel-drive

 

[Sam Harris]

Sorry, I do not know Sam. Check over at Performance Trucks forum. Lots of good info just googling 4L70E on the first page.

https://www.chevrolet.com/performance/transmissions/supermatic-4l70-e/two-wheel-drive

Thanks Sir!!

 

[eand28]

Ok all, I know my transmission is not going to last forever. I also felt a slip while driving the other day.. [emoji3525] I guess my BB tune will have to wait a bit. So, I’m looking for your recommendations for a good, reasonably priced upgraded transmission and torque converter. Currently just stock motor, with MIT intake and ARH longtubes. I’ll be tuning ASAP, and likely a stage 1 or 2 cam when I can. Someday, I’d like to supercharge her if it’s in the cards, but that would be down the road. So I’m looking for just a bump over stock that can handle a decent HP increase. I’m thinking I like the Cahall performance transmission here: https://cahallperformancetrans.com/4l60e,-65e,-70e
and likely their recommended protorque converter at probably stock stall speed.

Any recommendations, or places to stay away from are much appreciated!

I’d check out performabuilt or FLT both do good work on 60e’s. I had a guy in the philly area rebuild mine and it didn’t skip a beat in the 70k miles I put on it before the engine blew up. Had a bunch of sonnax parts and a modded transgo shift kit iirc

 

[Sam Harris]

I’d check out performabuilt or FLT both do good work on 60e’s. I had a guy in the philly area rebuild mine and it didn’t skip a beat in the 70k miles I put on it before the engine blew up. Had a bunch of sonnax parts and a modded transgo shift kit iirc

Thanks!

 

[ls1yukon]

A cautionary tale...

I was where you are 15 years ago, with an injured 4.8L that I needed to address and a "wish list" of power upgrades that I figured were far enough out that I could get away with a "good for now" transmission. There is nothing wrong with the FLT Level 4 4L60 and Yank TT2600 I installed first but with the weight of our trucks, it didn't handle the power of a stock LS6 engine with 317 heads, JBA shortys and MP112 Radix at 6.5 lbs (361rwhp/418rwtq on a Mustang dyno) for long before it started having 3-4 shift (clutch slipping) issues. Over the years since I've had the clutches replaced multiple times, and have built the LS6 into 383 ci, AFR 72cc heads, Speed Inc SC1 cam, Dynatech Maxx LTs, and replaced the MP112 with a MP122 at 8.5 lbs (554rwhp/585rwtq on a Dynapack dyno). After breaking an an Auburn LSD in the 10-bolt (and practicing my "lessons learned") I replaced it with a 9.5" 14-bolt from a 2008 Escalade, but honestly, the 4L60 has always been the Achilles heal and held me back from adding more boost, or adding power of any kind for that matter. I now have aFLT Level 5 4L80 that I will never have to worry about...I just wish I would have spent the money for the 4L80 in the first place.

Best of luck with yours.

 

[Sam Harris]

A cautionary tale...

I was where you are 15 years ago, with an injured 4.8L that I needed to address and a "wish list" of power upgrades that I figured were far enough out that I could get away with a "good for now" transmission. There is nothing wrong with the FLT Level 4 4L60 and Yank TT2600 I installed first but with the weight of our trucks, it didn't handle the power of a stock LS6 engine with 317 heads, JBA shortys and MP112 Radix at 6.5 lbs (361rwhp/418rwtq on a Mustang dyno) for long before it started having 3-4 shift (clutch slipping) issues. Over the years since I've had the clutches replaced multiple times, and have built the LS6 into 383 ci, AFR 72cc heads, Speed Inc SC1 cam, Dynatech Maxx LTs, and replaced the MP112 with a MP122 at 8.5 lbs (554rwhp/585rwtq on a Dynapack dyno). After breaking an an Auburn LSD in the 10-bolt (and practicing my "lessons learned") I replaced it with a 9.5" 14-bolt from a 2008 Escalade, but honestly, the 4L60 has always been the Achilles heal and held me back from adding more boost, or adding power of any kind for that matter. I now have aFLT Level 5 4L80 that I will never have to worry about...I just wish I would have spent the money for the 4L80 in the first place.

Best of luck with yours.

Thanks much for the info. I’m torn. The built 4L60 I’m looking at is supposed to be good for around 500 hp, but with the upgrades it needs to hold up to the weight of the Yukon, pushing 3k now. If I can do a 4L80 without too much difficulty, and for near that $ then its a no brainer. As just about everyone in this thread has pointed out, it would be very wise to migrate from the 4L60, to something much more stout. Can you give me details about what all is needed to convert to the 4L80? Would this be something my mechanic can do, or is it a specialty shop deal? My mechanic is a good friend, and knows his craft well, but he’s not the type to want to figure out what needs to be converted. If, however I have a comprehensive idea of all the details that need to come together, I think we’re in good shape.