94formulabird

I am wanting to switch to an auto from M6. I was going to do the 4L60E swap..but now am thinking of doing TH400 swap. I drive the car quite a bit..gets some racing on the street, and Im going to start going to the track quite a bit. Puts out 385/385 on a bad tune.....Mods are F13, LTs, Ported TB, LS6 intake, LCA, Panhard, Tubular Kmember, ect ect...I think with a TH400 and a 4000 stall it would be pretty damn fast. How are you guys doing on driving your cars alot...what about gas mileage and things like that. What are your setups like and what can you suggest for me. I want to do it once and do it right.

Nitrous fed SS

ttt

i would like to know some of these to, mainly is it driveable on the street?

BlackHawk T/A

iTrader: (3)

Yes its driveable, what do you think all the guys with TH350 cars did before they came out with an overdrive transmission?

It just wont have that extra gear for mileage.

98_Formula

iTrader: (15)

yea it'll be very drivable, sounds like what ur worried about is not "drivability" as much as it is gas mileage. The drivability of the transmission will have alot to do with ur stall and str choice. Make sure u get one that will lock up when u cruise, ur already goin to see a big change in gas mileage goin from a manual to auto, and even worse goin to a transmission w/o overdrive

1badA3Z

iTrader: (58)

very drivable and a th400 or th350 will be durable as hell,and yea u will haul *** with the rite converter and geat setup,its the only way to go hope this helps

raymond mckinney

iTrader: (4)

I drive mine all the time on the street! Th350, 4000 stall and trex cam.

gettinthere

iTrader: (3)

Why not go with a built 4l60e? I've got a H/C car with an RPM stage 5 4l60e. It'll hold all the power and I get an OD.

2002_Z28_Six_Speed

iTrader: (19)

Well, wouldn't it be easier to go to a TH400???

It is not eletronically controlled. The 4L60E is. Would be less modification to go with a TH400 since is he manual anyways. The computer won't look for the trans. As well as it would be more durable.

94formulabird

Well the TH400 would be cheaper than the stage 5 tranny or whatever..and i think it would be easier to put in...Im still not sure what to do. I drive the car quite a bit in the summer and would need to get at least 12 mpg in the car

N2RACINGLS1's

iTrader: (2)

You left out the most important information. What gear do you have in the rear end?

If you have 3:73 or less you should get better than 15 MPG. I have 3:90 in a three speed car and get around 17 MPG.

One other note if you have less gear than 3:73 you may need to lower your stall speed, due to the fact your LT1 motor has low end torque and the converter may slip alot at low speed since the converter is a non lock up converter for a 400 turbo.

You may want to look at a 3000 to 3200 stall! Just my opinion, maybe someone can add something to this. If you are going to spend 90% of your time racing than the 4000 is the way to go.

2002_Z28_Six_Speed

iTrader: (19)

Could always get the lock up conversion kit for the 400.

LS1SpeedAddict

iTrader: (9)

I have a stall in my 4L60E and I will be switching to a th400 eventually. Will my converter work with the th400?

z28convert

iTrader: (1)

nope. i had to buy a new one, vig. 3200 and i wish I had gone higher. ive got 3.23's and im probably getting 15-20 mpg. (no speedo or odometer so I cant tell)

the trans itself was 1100 shipped from b&m but I spent alot in conversion parts...
1) trans crossmember 200
2) body mount tq arm 500
3) tq arm x-member 100
4) flexplate 200
5) converter 700
6) driveshaft, slip yoke, conversion u-joints 400

....and yes it wasn that hard to put in, just read the sticky at the top of the trans section for whatever modifications need to be done

N2RACINGLS1's

iTrader: (2)

LS1 Speed ADD- Not to change the topic but your factory wheels look awsome on your car. I sure hope you have at least one extra wheel hidden away in your garage!! They are very hard to find.

Z28 Convert is correct you will not be able to use the 4 speed converter with a turbo 400.

Z28 Convert if you are not using your ABS, which I am not for sure even works if the car computer does not know how fast you are going. You can use the right front wheel ABS sensor wires to tap into the speedo wires and program you speedo that way. Just find someone in your area with LS1 Edit. Get the wire layout for the CPM on the right side of the engine bay and located the wires for the speedo and the wires coming up for the ABS speed sensor. You want know your speed in the burnout box but when you rollin you will.

z28convert

iTrader: (1)

really? i am not running abs just because the gear in the back broke when i got the loocker put in and didnt car to put it back in. but i think that I could still pull off the trick you said about tapping into the wires. when i do my cam and get my tune ill have to remember that. thanks for the info.

BTW- I think the 6 spd crossmember will work for the th400 with some slight modifications

Superman09

iTrader: (65)

So this trans will run o nthe street just as if i run my 4l60-e in 3rd? I have 3.23's. Not looking anytime soon but just curious to hold a 500 hp turbo set up if the 4l60-e takes a dump.

z28convert

iTrader: (1)

well i have 3.23's too and at 65 im at 2700-2800 rpms. 3300 im at 80 mph. its not that bad on the highway. I went to a higher stalled converter when i put the tranny in so i cant say it will act exactly like the 4l60 because i never felt lwhat it was like with a converter. but i can tell you there is no complaints from me.

Except, it short shifts unless you manually shift through the gears and hold it in gear longer. im guessing that has to do with the vacuum modulation. But other than that no driveibility issues from me.

94formulabird

Sorry..I need to clariy..I have a 2000 SS, I just never changed my name..and I have 342 gears since it is 6 speed...so around how much am I looking at spending to put a stalled TH400 in my car?

SUX2BU

iTrader: (14)

If your T56 is still good you can sell it and get most of the $$$ for your swap.
i daily drive a th350 with a 5100 non lock up stall and 4.10 gears. i get about 20 mpg on the highway and drive it 90+ miles a day. i did put some HUGE tires on the back to counter act the 4.10's. so it drives like i have stock sized tires and 3.42's.
60 mph is 3,000 rpm's and 70 is 3,500 rpm's.

SUX2BU

iTrader: (14)

heres about what i spent when i went from M6 to A3
fully built th350 with transbrake $1100
tranny pan $110
converter $900
dipstick $75
29.2K cooler $90
shifter $175
used the same driveshaft, made a custom crossmember and already had a body mounted TQ arm.
I LOVE my auto and wouldn't go back to an M6 if you paid me.