4L60E to T400 swap
Thread Starter
Staging Lane
Joined: Aug 2006
Posts: 66
Likes: 0
From: SE Michigan
4L60E to T400 swap My 4L60E finally gave up the ghost this weekend. I was thinking about replacing it with a Turbo 400. I heard that they are a pretty good transmission. Anybody here done this? How difficult is the swap? I was mainly thinking about the fact that the 4L60E has to be plugged in to the PCM. I want a good transmission but I don't want a really difficult swap.
94Z
LT1
383 Stroker
4:10 rears
30# SVO injectors
58mm BBK (w/ ported intake)
CAI
Head & Cam package to come
94Z
LT1
383 Stroker
4:10 rears
30# SVO injectors
58mm BBK (w/ ported intake)
CAI
Head & Cam package to come
10 Second Club
Joined: Apr 2004
Posts: 148
Likes: 0
From: San Antonio
I did one on my old race car. you have to get a converter for the speedo signal. I think the old 454 SS trucks had one. you will also have to get a new drive shaft, and cross mount. (I think BMR makes one now) I fabed mine up from a 6 speed cross mount and some other parts. Your shifter, if stock, will be out of alignment from where it is indicated..ie 1, 2, 3, n, p. It's not that bad to do. You might look into a th350 if your pushing less then 700 hp or so.
i did the th350 swap into my vert.
it was really easy. the new trans will bolt up no problem. you'll need a new stall tho. you can fab up a trans mount or purchase one. i used the stock driveshaft tho. i got a th350 with the longer tail.
it was really easy. the new trans will bolt up no problem. you'll need a new stall tho. you can fab up a trans mount or purchase one. i used the stock driveshaft tho. i got a th350 with the longer tail.
How is the car used?
If it is a driver, no OD, no lockup, blows in a big way, the no OD may not be that ig a deal alone, but combine it with no lockup and the fact no lockup will make you pick stall concervatively and you will quickly realize the three speed swaps are best left to track cars.
The 4L60E can be built to hand pretty serious power, only problem is finding someone competent to build it. The 4L60E gets a bad reputation because there are more incopent fools building it than there are good shops, and the incompetent guys tend to blame the design rather than learn from their mistakes.
If it is a driver, no OD, no lockup, blows in a big way, the no OD may not be that ig a deal alone, but combine it with no lockup and the fact no lockup will make you pick stall concervatively and you will quickly realize the three speed swaps are best left to track cars.
The 4L60E can be built to hand pretty serious power, only problem is finding someone competent to build it. The 4L60E gets a bad reputation because there are more incopent fools building it than there are good shops, and the incompetent guys tend to blame the design rather than learn from their mistakes.
to add to what Dwayne said, the 4L60 and 700 R4 have a low 1st gear. Your 4.11's will effectively (or comparatively) be turned into a 3.55 gear with a Th 350 installed due to the difference in 1st gear.
For a drag car only or something running lots of NOS and well in the 10's . . . . a TH 350/400 can be justified. Anything less and a "properly built" 4L60 can handle the abuse while giving you a better launch (due to lower 1st gear) and you still have OD and the lock up feature so RPM on the highway can be 2400 RPM @ 65 MPH as opposed to 3500 RPM with a TH 350 (no overdrive), 3600 stall and no lock up feature (both based on 4.11 gears and 26" tires).
My 3760 lb car has ran lots of 11.30's 1/4 mile and 7.20's 1/8 mile (11.21 and 7.13 best ET's) with 3.42 gears and "built" 4L60 from Cahall Performance Transmission and never had a problem.
No shifter installation problems, no driveshaft change, no TQ arm relocation problems, no brackets/mounts to buy/make. Just plug-n-play.
Really depends on the goals of the set up but make sure and consider all options before just throwing a TH 350/400 in because "someone else" said you need one and could not get "their" 4L60 to last. TH 350/400 IS the right answer for some but alot of people would be happier with a 4L60 if built by the right person/shop.
Lloyd
For a drag car only or something running lots of NOS and well in the 10's . . . . a TH 350/400 can be justified. Anything less and a "properly built" 4L60 can handle the abuse while giving you a better launch (due to lower 1st gear) and you still have OD and the lock up feature so RPM on the highway can be 2400 RPM @ 65 MPH as opposed to 3500 RPM with a TH 350 (no overdrive), 3600 stall and no lock up feature (both based on 4.11 gears and 26" tires).
My 3760 lb car has ran lots of 11.30's 1/4 mile and 7.20's 1/8 mile (11.21 and 7.13 best ET's) with 3.42 gears and "built" 4L60 from Cahall Performance Transmission and never had a problem.
No shifter installation problems, no driveshaft change, no TQ arm relocation problems, no brackets/mounts to buy/make. Just plug-n-play.
Really depends on the goals of the set up but make sure and consider all options before just throwing a TH 350/400 in because "someone else" said you need one and could not get "their" 4L60 to last. TH 350/400 IS the right answer for some but alot of people would be happier with a 4L60 if built by the right person/shop.
Lloyd
agree with lloyd i have the same tranny and ive been 6.30's on the 1.8 mile several times...and driven it on the street a bunch its not radical no shifting just like stock...over 3 years no problems...
Thread Starter
Staging Lane
Joined: Aug 2006
Posts: 66
Likes: 0
From: SE Michigan
Thanks Lloyd, that's exactly what I needed to hear. I think I have a guy near me that can rebuild my 4L60E the way I want it. BTW, you'll be getting to know this car this winter when I send the heads down to you.
Trending Topics
sounds good.
Make sure and get some eferences and talk to the people running his transmissions in 10 and 11 second cars with no problems. Everyone will claim they can do it but not as many can accomplish this and have the trans last.
Even if he offers a $$$ back guarantee or repairs for free, I would rather not have to pull and stab the trans a cpl of times while he figures out what he is doing wrong or blames it on the tune. Figure is getting stranded at the track or on the street with wrecker fees, wrecker scratching, scraping bumpers while towing, etc, all for a lil $$$ save on a trans build.
You could be left with a ruined converter even if he gives your $$$ back on the trans and a lot of hours invested in R/R of thrannys. Not much fun at all.
I have no idea who you are using or what they do, just make sure they CAN build a good trans by listening to people that are running them in cars equal to yours as far as weight/ET. Also ask if he ever had to pull/adjust anything or just install and go.
This might save you some $$$ or you might have found one of the few people that can build a good 4L60 at a good price. Most people that have this ability know what it is worth and are charging for there skills. Some are chaging the same price and STILL can't build one correctly.
Just do lots of research and maybe it will save you some $$$.
Lloyd
Make sure and get some eferences and talk to the people running his transmissions in 10 and 11 second cars with no problems. Everyone will claim they can do it but not as many can accomplish this and have the trans last.
Even if he offers a $$$ back guarantee or repairs for free, I would rather not have to pull and stab the trans a cpl of times while he figures out what he is doing wrong or blames it on the tune. Figure is getting stranded at the track or on the street with wrecker fees, wrecker scratching, scraping bumpers while towing, etc, all for a lil $$$ save on a trans build.
You could be left with a ruined converter even if he gives your $$$ back on the trans and a lot of hours invested in R/R of thrannys. Not much fun at all.
I have no idea who you are using or what they do, just make sure they CAN build a good trans by listening to people that are running them in cars equal to yours as far as weight/ET. Also ask if he ever had to pull/adjust anything or just install and go.
This might save you some $$$ or you might have found one of the few people that can build a good 4L60 at a good price. Most people that have this ability know what it is worth and are charging for there skills. Some are chaging the same price and STILL can't build one correctly.
Just do lots of research and maybe it will save you some $$$.
Lloyd
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Joined: Nov 2001
Posts: 10,023
Likes: 6
From: LT1 land...the "409" of the 90s!
As many have said the three speed swap is a pretty much a race only deal. The ONLY reason We oput one in the blue car is it is pretty much a track car that I drive to work every once in a while. no real freeway use. Althogh it does hum down the road at around 3,200 if you want 
It was cheaper then buying a new input and out put shaft to continue running nines with the 4L60E
That being said we do have nine second cars running on 4L60Es. When built properly they work just fine
It was cheaper then buying a new input and out put shaft to continue running nines with the 4L60E
That being said we do have nine second cars running on 4L60Es. When built properly they work just fine
