Upgrade transmission recommendations?

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Sam Harris

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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!
 
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Sam Harris

Sam Harris

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Hmm, 03 Yukon right? 4 speed auto. First thing that rings in my mind is can it be swapped to the NNBS 6 speed auto for better mileage, drivability and longevity.


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Yessir. That would be sweet.. however, I’m looking for as cost effective as possible. I also believe if the 4l60e is properly built it should have no problem holding up to a couple hundred HP / TQ increase.
 
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Sam Harris

Sam Harris

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HiHoeSilver

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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 think @Rocket Man is running Performabuilt.
 

randeez

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6l80 would need a stand alone with gen3 ecm would prob count that out.

there are still a few people/companys doing r&d for the 4l60... not so surprising since its found in so many cars/trucks but i dont know how budget minded its going to be to get one to hold a lot of hp compared to a relatively stock 4l80.

80e would need different transfer case and a little bit of wiring changed.
 
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Sam Harris

Sam Harris

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Thanks @randeez. I’m not looking for any huge hp increases right now. I figure an extra 100-150-ish tops.. I mean, I’d love to build a turbo, built 427.. but for now I’ll have to live vicariously through your build. [emoji16][emoji106][emoji631]
 

randeez

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As long as you also feel the struggles <3

Nah what I mean is a used low mileage 4l80/converter/flexplate $1000, some wiring (free or $150 for swap harness), transfer case can be found under $500, drive shaft mods will be another couple hundred.

$2k doesnt buy a very built 4l60, or maybe it does? Dunno havent looked into them much
 

Wylie_Tahoe

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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.
 

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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

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...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
 
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Sam Harris

Sam Harris

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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

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eand28

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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
 
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Sam Harris

Sam Harris

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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

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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.
 
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Sam Harris

Sam Harris

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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.
 

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