LS2 4l65e dead.. rebuilt or go 4l80e?

Oct 14, 2008
6,382
113
Melville,Saskatchewan
Yeah, a stock truck convertor probably stalls around 1500 rpm, not good.
 

Supercharged111

Royal Smart Person
Oct 25, 2019
1,032
113
Stock stall depends on what you pull it from. I got my 4L80 from a 350 truck, so stalls a little north of 2000. My dually stalls around 1600. I 4L80 swapped my 1500 when the 4L60 took a dump on me. The taller gearing was very noticeable. . . with a stock converter. It's larger in diameter and a good 20-30# heavier than the 60's so has a significantly higher moment of inertia. If I had the same 2000 stall, but 2" smaller in diameter and 20-30# lighter the truck would rape. The gears are much closer together, so shift recovery kicks *ss with a stock stall. The overdrive isn't night and day, but did help keep the truck locked in OD with a trailer. All that and the peace of mind you get with the swap make it 100% worth it. My 1500 trans is a basic rebuild with Superior shift kit. It's been living behind a mild cammed supercharged 350 Vortec for the last 50k. Probably time for a filter or a flush now. The stock 4L80 in my dually, at around 150k, has been supercharged most of its life as well. Pretty sure I gave it its first flush this spring. I lived for 80k with a 3000# welding bed on its back occasionally pulling trailers. I've been nothing short of impressed with the 4L80.
 

Anubis

Royal Smart Person
Mar 30, 2012
2,176
113
West Michigan
I put an 4L80 In my 442. NO tunnel work is required and cooler lines are accessible. As noted you will need a saws all to cut the sides of the trans housing for header / exhaust clearance. My car has the factory 3.73 8.5 rear end and first gear is definitely not too long. I have major traction issues and wish gearing was taller. Your 3:42’s should improve this. I’ve read that some dyno comparisons between a 4L60 and 80 show minimal difference in parasitic loss.
 

Injectedcutty

Not a d*mn GN
Supporting Member
Nov 24, 2014
5,472
113
Louisville, KY
I put an 4L80 In my 442. NO tunnel work is required and cooler lines are accessible. As noted you will need a saws all to cut the sides of the trans housing for header / exhaust clearance. My car has the factory 3.73 8.5 rear end and first gear is definitely not too long. I have major traction issues and wish gearing was taller. Your 3:42’s should improve this. I’ve read that some dyno comparisons between a 4L60 and 80 show minimal difference in parasitic loss.
I have to 2nd your statement on traction issues with the 3:73's and 3400 stall in my 80E. I just left a car show and for some odd reason the tires just decided to start spinning. Next thing I knew there was smoke and I was accelerating at a high rate 😁!!!
 

Rktpwrd

Comic Book Super Hero
Feb 2, 2015
2,893
113
Calgary, Alberta, Canada
I have to 2nd your statement on traction issues with the 3:73's and 3400 stall in my 80E. I just left a car show and for some odd reason the tires just decided to start spinning. Next thing I knew there was smoke and I was accelerating at a high rate 😁!!!
Weird how that happens, I have the same issue sometimes.
🤔
 
  • Like
Reactions: Injectedcutty
Oct 14, 2008
6,382
113
Melville,Saskatchewan
I don't like the gearing in either of these transmissions. With all the mods needed to fit a 4L80E under my 70 plus at least a $500 core which still might need rebuilt, bell housing adapter, a controller and an expensive converter, a TH2004R with mods is my choice. But as said, if you have the power where a TH400 or 4L80E is needed, their tall gearing and .75 OD gear in the latter's case won't matter as much. If anything you want the 2500 rpm highway rpm with a big cam. I figure 70 mph for me will be perfect, around 2200 rpm. I am surprised any truck converter will stall at 2000 rpm plus, most stall around 1500 rpm for towing. Probably because a 3/4 ton with a 350 needs the higher stall to get out of it's own way.
 

Supercharged111

Royal Smart Person
Oct 25, 2019
1,032
113
I don't like the gearing in either of these transmissions. With all the mods needed to fit a 4L80E under my 70 plus at least a $500 core which still might need rebuilt, bell housing adapter, a controller and an expensive converter, a TH2004R with mods is my choice. But as said, if you have the power where a TH400 or 4L80E is needed, their tall gearing and .75 OD gear in the latter's case won't matter as much. If anything you want the 2500 rpm highway rpm with a big cam. I figure 70 mph for me will be perfect, around 2200 rpm. I am surprised any truck converter will stall at 2000 rpm plus, most stall around 1500 rpm for towing. Probably because a 3/4 ton with a 350 needs the higher stall to get out of it's own way.

TCI makes a gearset for the 4L80, gives a more TH2004R like 1&2.
 
  • Like
Reactions: olds307 and 403

Texas82GP

Just-a-worm
Supporting Member
Apr 3, 2015
5,945
113
Spring, Texas
If you use a stock converter, make sure the stall speed is at least as high as the stock converter from the GTO.
 

Patobusta

Not-quite-so-new-guy
Thread starter
Jul 2, 2017
20
3
Thats what i was thinking. But how can you tell? Are there any markings on the converter as to check?

I also heard (not that I have any experience or knowledge) that same converter might stall at different speed on different engines.. notably bigblocks tend to stall the same converter at 300-600 rpm less than a small block.
 

Please support GBodyForum Sponsors

Classic Truck ConsolesDixie Restoration DepotMike's MontesP-S-TSouthside Machine PerformanceUMI Performance

contact[email protected]for info on becoming a sponsor