Fresh 904 race trans, 2nd to 3rd shift issue

-
B

B3422w5

Well-Known Member
Joined
Feb 9, 2017
Messages
3,760
Reaction score
4,658
Location
Portage michigan
When at the track under full power, second to third shift feels like it actually drags the engine down, almost like it bucks a second before the shift is completed.
Has TA Reverse man valve body, putting around on the street seems fine, don’t notice anything, first to second shift at track seems fine too.
my builder swapped out an A&A brake I never used for this TA valvebody during the freshen. Has 5.0 band lever if that matters.
 
I adjusted the band on the 727 I was working on, and it didn’t help with the shift overlap. But this 727 you could feel at lower speeds. Yours is different, so I would try a band adjustment first
 
It's hard to say, as I don't know how the transmission was setup before, or this time. This transmission inherently gets stuck in two gears at once (overlap/bind) on the 2-3 shift and we do a lot to overcome it. It has a lot to do with:

- Lever ratio
- 2nd gear apply servo spring
- 3rd gear piston spring count
- Type and brand of valve body

The lever can typically be changed in the car with a small race converter with a couple of 1/4" extensions and a wobble.

We use 4.2 on all builds except in a few situations we'll use a 5.0.
 
What front servo and 1 or 2 springs in it? How many springs in the front clutch? What is the clutch clearance in the front drum? The front apply lever can make a huge difference as well as the band adjustment. I use the solid band. Kim
 
oldkimmer said:
What front servo and 1 or 2 springs in it? How many springs in the front clutch? What is the clutch clearance in the front drum? The front apply lever can make a huge difference as well as the band adjustment. I use the solid band. Kim
Click to expand...

about all I know is it has a solid red band and he utilized all the stuff in the A&A rebuild kit. Alto/ Koleen, like came out. Same 5.0 lever used in rebuild.
What he found in the trans was smoked front band and rear clutches welded together.
my symptoms were( ultimately) no reverse, bad slip in first, and flare from second to third( the flare appeared first, last outing last year.
the other symptoms appeared first outing this year.
trans previously had A&A older brake valve body( I always foot braked it)
it worked perfectly for several seasons until the flare showed up. Zero issues.
Now, swapped out brake valve body for TA footbrake valve body( I swapped them for free labor as I never used brake anyhow)
Now, first time out with trans, bad overlap. Almost like I tapped the brakes on the 2/3 shift.
I did notice it got perhaps a bit better after a few passes, but not much.
Builder seems to think a band adjustment should fix it, hope so, getting it in and out was a long, taxing ordeal without a lift.
 
Last edited:
Found out directly from Turbo action the band should be adjusted 1.5 turns.
told him I suspected it was at 2.5. Described what it was doing, he said setting it to 1.5 he was almost positive would fix it.
it’s spelled out in the instructions on the TA site as well. He said actually 1 1/4 to 1 1/2, but as I had already made passes, 1.5 will be fine.
2.5 will cause the overlap I am having 2/3 shift
 
Thanks for the updates! Hopefully that‘ll cure your woes.

The 5.0 lever I found interesting. I haven‘t heard that recommendation in a long time.
 
I am gonna NEED YOU GUYS if I live long enough to get an A500/ 44RH/RE with manual VB into mine.
 
You must log in or register to reply here.
-

Back
Top