Automatic Transmission - Th400 slipping at the track (question)




Tireburnin
09-14-2005, 04:29 PM
I'm running a TCI 3500 stall and built th400 behind my LT1.

At the track this past weekend I put the ET streets on and made a run. It was the first (and only run) with the th400 as I found it was slipping pretty badly. The car bogged hard and I could feel it slipping on the launch. Then when I went to shift the car at 6400rpm on the stock tach which is likely slow, the car bounced off my limiter which is set at 7000rpm. Then I was forced to shift into 3rd on the 8th mile track because I heard the car bounce off the limiter in second.

I thought it might have been the tach being really slow, but I only trapped 89mph and was forced to shift into 3rd gear with 3.42 gears which should be good for 100mph in 2nd gear.

On the drive home everything was fine and shifted normally. I had the street tires on again and from a roll, I shifted 1-2 and 2-3 without any slipping or issue. The problem was only pronounced at the track with lots of traction.

What would cause the slipping only at the track? Bands? Pressure/clutches?

The fluid level was fine, if not a bit high. The shifts were very mushy and soft at the track, but felt normal on the street. Fluid temp was about 185-195 on the track run.

Any input or things to adjust/look for would be appreciated.


Craig Burnett
09-14-2005, 08:12 PM
dangerous to trans--- make 1 wot run just to feel 1-2 and 2-3 shifts with vacuum guage installed- Let me know how much vac you have while running- may be able to use tee bleed trick to up line pressure- tee a glass fuse end with calibrated hole drilled thru - can enlarge at track if need to - are you running a blower? craig

02' hawk
09-14-2005, 08:18 PM
dangerous to trans--- make 1 wot run just to feel 1-2 and 2-3 shifts with vacuum guage installed- Let me know how much vac you have while running- may be able to use tee bleed trick to up line pressure- tee a glass fuse end with calibrated hole drilled thru - can enlarge at track if need to - are you running a blower? craig
What is that? "the tee bleed trick"


Tireburnin
09-14-2005, 09:54 PM
dangerous to trans--- make 1 wot run just to feel 1-2 and 2-3 shifts with vacuum guage installed- Let me know how much vac you have while running- may be able to use tee bleed trick to up line pressure- tee a glass fuse end with calibrated hole drilled thru - can enlarge at track if need to - are you running a blower? craig

You want me to test the vacume at WOT? Shouldn't it be zero at WOT and like 12-14ish at idle? I'll give it a test and see if I'm pulling anything. What should I look for?

And I have the vacume line pulling vacume from a T on the side of the manifold. I think it's sharing a line with the EGR vacume line.

And I don't run a blower. I have a heads/cam built 355 with 11:1 compression and a bunch of nitrous. I was running motor that night.