Went to the 8th mile track to test-n-tune and killed my tranny on the first good pass. It's slipping in 3rd and Drive now.

I DO NOT want to get historic and go to three gears. I intend to drive this thing on the street/highway.

I checked 4L80E's. They are close to $4000 solutions by the time it's all said and done. I may just get good at swapping out trannys and get a backup ready to go... just plan on one season per build. To get another 4L60E back up is the only way I'll make this season to the track. Heck... I've built TH350's whenever I wanted. I may get the tools for this build throughout the year and just learn to do it myself.

 

that sucks to hear. Why not get a built T56 ?

 

why not a GOV unit on the back of a built TH350 with lockup?

 

Mike, if you go with 3.42's or less on your rear gears, you can still drive on the highway with the TH400 with no problem. You can even go with 3.23's if you want, just get a tad more stall, and stick with 26" drag slicks at the track / 26" drag radials on the street.
You'll be better off with the TH400 and trans brake, even if you take the rear gears way down so you dont' tach out.

 

TH400's are fun, I really don't regret getting one, one equiped with a brake makes it a dangerous setup on the street, its hard for 6-speeds to hang at all off the line unless they are setup w/slicks a 12-bolt and a good clutch

I fry my 28x12.5x15 et streets at 18psi for about 90ft, thats without using the brake, I'm going to do some track testing pretty soon.....

 

Cost break down
4l60 or 80 built to hold up to our power=$3500-4500
350 or 400 turbo with gear venders od=$1500(tranny)+$2000(gear venders od)=$3500

Once I compared the two cost and then added in the 400 turbo transbrake and being more reliable, I went with the Rossler 400 turbo/gear venders od set up and I love it.
Tom

 

Thanks for all you guys advice. Some more $$$ estimates for those other suggestions would be nice.

Why 26" tires? I'm using 28" MT ET Streets and was planning on going to a Raidal for the streets that's close to 28" so I won't have to keep chainging my tune when I swap tires (better gas mileage and the 25.65 or 26.0's get too roasted anyway).

Also, I was thinking about going fully manual, too, with the automatic. It may not be as much fun without a rachet shifter designed for our cars, but I won't have to worry about the potential short-shifting problem anymore. That happened to me at the 8th mile track again. Even feathering it, each run I just spun down the track all the way through first gear and when i tried to give it less part-throttle, it short-shifted on me again.

Four runs.

The first run, it stalled off the line... all that street tuning and that never happened. But, something about getting a little bit of hook-up at the track changes the whole equation. I had passed the tree and was backing up when the guy started the lights anyway, so I thought maybe there was some wierdness with how quickly I had to get forward again trying to catch the lights.

But, next run, at the top of 1st it stalled, then did some wierdness down the track. It was almost like it was losing boost intermittently. I crawed under the car wondering if I'd popped a boost hose loose from the extra boost (even thought I'd re-tightened all of them). Well, no. But, my vacuum hose from the purge valve had come off. At least it was minor.

On the 3rd run is when I got the short-shift.

1~2 3700 RPMs
2~3 4500 RPMs

The engine has so much torque, and the tires were spinning so much, I didn't even realize it had shifted like that until I checked the autotap log after the run. Even with all that, I managed a 7.58 at 95.4 MPH.

4th and last tuning run. I decided to shift myself. (With these electronic A4's, you know that's a dicey proposition at best. I managed to get SOME hook-up by feathering all the way thru 1st, and giving it full throttle once I was solidly in 2nd. But, upon shift to 3rd, though the engine was revving, I was going nowhere.

According to EFILive, I ran in 1st and 2nd up to 89.5 MPH in 6.0 secs. (It shifts to 3rd just before I get to the end of the 8th mile.)

Oh, well...

 

you need to give me a ride some time, and use the Tbrake

id say that is your best choice. Even though i really like a manual, i am going to switch out to the T400 in a year or two. I just dont see any other way with the power and times i want to be at. Ive talked to alot of people and they said that since they had their T400 they have never had to touch it.

 

3.42's or less out back with a 28" slick might bog off the line, unless youve got enough low end torque to get that low of a gear ratio spooled up off the line. I'm putting down 530RWHP, and the 26x11.5 slicks seem to work best with 3.42's
If you swap to a TH400, changing tunes won't be necessary since the computer will not be involved in the shifting.

 

4L60s suck

I have a manual/automatic valve body in mine and still use the vacuum modulator so it drives just like normal - except for no OD. I miss OD but even with a 3.70 and 27" tall tires 3,000 rpm is ~60mph which isnt that bad. I have over 200 passes on the thing, broke an input shaft/direct drum a while ago, cost me 44.00 in parts and a couple hours of my time to fix it. I can rebuild a TH350/400 with my eyes closed and parts are super cheap, hard to beat except for the OD thing.

4L80s are huge/heavy/expensive, 200r4 is a decent deal if want OD but it costs a lot to build a nice one. T56's and clutches arent going to hold up long if you really beat it a lot - its a tough decision..

 

A Rossler T400 will easily handle your power.

 

Sorry to hear you had problems Michael.

If you try the 4L60E one more time maybe go with a bigger trans cooler, what do you have now?

I have the big 28,000 GVW one now, with the big fittings.

I like my new T400 and 3.50 gear combo. But if you are mostly a street car I can understand.

 

Thanks, PSJ... I've often wondered if I would benefit from a taller gear since 1st gear is totally useless at WOT on the street... and also spins at all but the BEST prepped track. But, I figured going to 28" ET Streets would help. It did, but not enough.

I don't want to do slicks. To me, then it's not true street (well, not to me... and I don't know if I'd EVER keep a tranny right now). Perhaps I'll go back to 3.42's in my 12-Bolt setup. But, I'm afraid to change semi-permanent things like rearend gears or torque stall. I've only got so much money to play with.

With all the torque I have, would I REALLY lose that much to lower my stall, too? Or maybe get a higher STR?

I don't know... It's probably about perfect. I drop to about 4800 RPMs when I shift at my HP drop-off point. Of course, my torque is at it's peak all the way back in the low to mid-3000's and HP is pretty flat starting about 4000, so how much difference does it REALLY make?

 

Then, too. I LIKE the gear ratios of the 4L80E. They make more sense for a high-HP car. 1st and 2nd gear are too short in our car, IMO.

 

I think the 4L80E would be different. I don't think I've read about anybody on here with one. If my trans. ever goes I'm talking to Rossler, I've only heard good things. I had the py3400e in but put my 2600 back in because I didn't like the looseness for the street. With the available torque from the cubes the 2600 feels waaaay better all the way around. I have been keeping the 3400 so if I ever decide to go for the best E.T. I might put it back in but as time goes by it seems more and more unlikely.

 

4L80E would be cool:
+stronger
+John Meaney has one
+T400 + od for the most part
-heavy
-totally custom install
-have to clearance trans tunnel
-could be $4K when all done
-need tci trans 'troller to control the trans (I think)

 

If you go with TH400 setup get a 2.75 first gear option. There are cars running 8's with the 2.75 first without problems. Then you could run a less aggressive gear without affecting your launch/short times.

 

Cool!

You guys have made this a great thread!

I'm leaning towards a final solution of 400+OD.

My immediate solution will be to get this 4L60E back in. The last builder said he'd fix it. Maybe he is going to honor it as having should have lasted. He thinks it should have. I may have to pay for parts.

 

If I had to do it over I would for sure get the lock up option along w/the 2.75 more "stout" first gear

 

I jacked the car up and drained the fluid to start pulling it out.

I used a clean drain pan, and sifted my hand thru the fluid. Absolutely zero metal or clutch material in the drained fluid. The fluid is clear and pink... like new. It doesn't smell burnt at all... it smells sweet and clean.

Well... this time IS different. I didn't just lose 3rd and 4th as I always have before. I've never had it slipping in 4th, only to be able to shift it back to 3rd and move forward. Also, I wonder if the lack of RPMs rising quickly in 3rd at the track was just the initial layback at the bottom of 3rd gear. What DOES happen on the street is it surges after I get to about 2500 RPMs in 3rd. If I shift to 4th, I can cruise all day. But, it slips as soon as I give it throttle.

Instead of taking it out, I'm gonna let my transmission guy drive it. He thinks it's possible I broke something instead of burning 3&4 clutches this soon. He still may have to go in it, but driving it, he may find he can just go into the valve-body on the car.

I don't know. Any of you guys have this problem with the 4L60E?