4l60 vs t400
Thread Starter
Teching In
Joined: Jan 2013
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4l60 vs t400 I have a 2001 Pontiac Trans Am. Car weight is 3650 with me in it. I have a moser Fab 9 inch with 4.11 gears and a wavetrac in it. I have tubular lca, pan hard bar, bmr anti roll bar, bmr sub frame connectors, bmr tubular k member and umi upper and lower control arms. Engine mods I have a msd airforce intake, 102mm holley throttle body 42lb injectors, btr stage 3 cam, btr spring kit, btr trunnion upgrades, ati lower pulley.
I am having issues with the 4l60 Trans it wouldnt shift 2-3 at wot it would bounce off the reev limiter is the first problem. 2nd problem is we were comannding it to shift at 6800rpm it would shift 1-2 at 6400 and 2-3 at 6300 and bounce off the limiter. when it shifted the rpms would go down to 3800 rpm on both shifts and I would go through the traps at 6000rpm. We changed converters another 3600 stall thinking 1 converter was to tight and tried to losen it up. Redid the tune and lowered the shift ponts to 6500rpm for 2 passes the 2-3 shifts were good. then it started hitting the limiter again and this time it was at 6100 rpm. I am tearing the trans out of the car. Not sure if I should rebuild this 4l60 or go to turbo 400. Does anyone hve experience with the switch with the same mods? My thinking is if the car is going to mis shift it will be because of me and not the computer. plus I am in the process of building a turbo engine. everything I have done to the car is for future engine mods so far. I am thinking the 4l60 trans is warn out and that is why the inconsitncy. I had a best 60 ft of 1.68 with a stock engine and a 3600 stall lock up converter. since the engine mods leaving the same way best 60ft times 1.71. I do have drag radials and the tires aren't spinning at the line. Sorry for the long post but Just at a cross roads here on what to do.
I am having issues with the 4l60 Trans it wouldnt shift 2-3 at wot it would bounce off the reev limiter is the first problem. 2nd problem is we were comannding it to shift at 6800rpm it would shift 1-2 at 6400 and 2-3 at 6300 and bounce off the limiter. when it shifted the rpms would go down to 3800 rpm on both shifts and I would go through the traps at 6000rpm. We changed converters another 3600 stall thinking 1 converter was to tight and tried to losen it up. Redid the tune and lowered the shift ponts to 6500rpm for 2 passes the 2-3 shifts were good. then it started hitting the limiter again and this time it was at 6100 rpm. I am tearing the trans out of the car. Not sure if I should rebuild this 4l60 or go to turbo 400. Does anyone hve experience with the switch with the same mods? My thinking is if the car is going to mis shift it will be because of me and not the computer. plus I am in the process of building a turbo engine. everything I have done to the car is for future engine mods so far. I am thinking the 4l60 trans is warn out and that is why the inconsitncy. I had a best 60 ft of 1.68 with a stock engine and a 3600 stall lock up converter. since the engine mods leaving the same way best 60ft times 1.71. I do have drag radials and the tires aren't spinning at the line. Sorry for the long post but Just at a cross roads here on what to do.
TECH Junkie
Joined: Dec 2012
Posts: 3,618
Likes: 1,328
From: Iowa
You need to ask yourself a few questions when considering your transmission combo. Answer them here and we can help ya choose
A. What is a REALISTIC power goal for the car in the next 12-18 months?
B. What is your ratio of street to track? 90/10? 50/50? Etc
C. How much do you value computer shift consistency?
D. What is your budget? Do you have only 1500 to spend? $2500? $3500? Need to know a budget before you can really go down any path
60e, glide, th400, 4l80e, th350...all possibilities depending on what direction you're headed
A. What is a REALISTIC power goal for the car in the next 12-18 months?
B. What is your ratio of street to track? 90/10? 50/50? Etc
C. How much do you value computer shift consistency?
D. What is your budget? Do you have only 1500 to spend? $2500? $3500? Need to know a budget before you can really go down any path
60e, glide, th400, 4l80e, th350...all possibilities depending on what direction you're headed
Thread Starter
Teching In
Joined: Jan 2013
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Realistic power goals is about 12-1400rwhp. I am planning to go twin turbo. I dont mind paying the money now cause eventually I am going to need too. I street drive the car to car shows so about 20% of the time.
TECH Junkie
Joined: Dec 2012
Posts: 3,618
Likes: 1,328
From: Iowa
So you plan to...in the next 12 months...go from a cam only car to 1200+ hp with twin turbos?
If you're ready for that jump in power, you should know enough to not be asking 60e or th400
Th400 is an obvious choice with the 4l80e being a 2nd option if you will do lots of street driving and/or if you want computer controlled shifts.
If you're ready for that jump in power, you should know enough to not be asking 60e or th400
Th400 is an obvious choice with the 4l80e being a 2nd option if you will do lots of street driving and/or if you want computer controlled shifts.
Thread Starter
Teching In
Joined: Jan 2013
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The turbos might not be on next year. Hoping the engine is built by next spring. I have driven a faster car but unfortunatly losing a job I needed to sell the car. I am building a car with my son so we are doing things at a slower pace and want to have fun with the car. I dont want to go slower than what we are now, but I dont want to keep putting money into a part that will be replaced in the future. If it takes 2 years to get to that power level thats fine. But to rebuild a trans every year when I can put a trans in now that will either not make us lose mph and et and we can braket race it. Then I would rather do it. I have heard people say a t400 wont react and will be alot slower because of first gear. But I wont have to keep rebuilding a trans and I can use that money else where.
TECH Junkie
Joined: Jun 2008
Posts: 3,203
Likes: 1,391
From: Nitro Alley
I have an Alcohol Funny car for sale... it's complete you don't need to build anything for it.
I agree with Maroon Monster... that a big power jump...
But if you want a bigger power jump... Buy my funny car!
I agree with Maroon Monster... that a big power jump...
But if you want a bigger power jump... Buy my funny car!
Teching In
Joined: Nov 2015
Posts: 35
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I can only give you some info from my own experience. I have 2 twin turbo cars one is an 87 GN that has a turbo 400 with a gear vendors overdrive, the other is a twin turbo 96 impala ss with a 4l80e. I believe you are going to continue to put money into rebuilding those trannys i don't care who your tranny builder is i went down that road with the 4l60. I would either go with a 400 or you are gonna have to build a 4l80e that can handle the power and they can but you will pay a pretty penny to build it right . I would stop building 4l60's you will never have them hold up under good power. I would say if you do the twin setup go turbo 400 if street driven or highways are important 4l80e but they are big and heavy and cost a ton to build right with converter on that tranny you get what you pay for I've had them all and broke them all accept the turbo 400 and that has gone 8.20's
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TECH Junkie
Joined: Jun 2008
Posts: 3,203
Likes: 1,391
From: Nitro Alley
Why does everybody think the 4L80E is such a heavy transmission???
A 4L80E with the same type and size of converter as a 4L60E is about 35 pounds heavier...
How is that even going to make a difference in a street car?
A 4L80E with the same type and size of converter as a 4L60E is about 35 pounds heavier...
How is that even going to make a difference in a street car?
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