I just put new clutches and steels in my 904, I also upgraded the band strut and put an old A-1 trans brake valve body in(old but new in box). Now this was my first time to dig all the way into a transmission, so keep that in mind.

I have not driven the car, just run it on stands. I also have the trans brake wired up temporarily because I was running out time. 1st engages good, it hits 2nd hard on the stand. The high gear shift doesn't bang but it goes into high gear well, it will also overpower the brakes in high gear. The trans brake works under light throttle and me holding two wires together lol. Reverse works but it never really thumps into gear and from what I can tell it probably wouldn't pull the car on the ground.

First thing I am going to check is the low reverse band adjustment, I honestly don't recall setting it but I know I did the 2nd gear band. I guess if I get the pan off and the low reverse band is adjusted properly the next step is to swap my old trusty Turbo Action Valve body in.

Thoughts?

EDIT-Yes I am engaging the brake for reverse, I forgot to mention that originally.

Do you have the trans brake engaged in reverse? Many trans brake valve bodys need the brake engaged to actuate reverse.
Doug

Yes, I should have mentioned that I am engaging the brake for reverse. Reverse does work but you have to rev it up a little and it will start to move the tires, it goes into every other gear very firmly.

I think I am going to just swap my TA valve body back in and maybe send this one back to A-1. I paid an extremely fair price for it because it had been on someone's shelf for ages, it might have a case of shelf rot lol.

Personally I’d set it on the ground and see what happens.... air check the rear servo if/when you remove the valve body

I jacked around with it more last night. The Band adjustment was in check, So I swapped the TA valve body back. It was too late to fire it off when I got done so I will get it checked later today.

If it still doesn't work I will probably wait and see if I get signed up for drag week before I mess with it again lol.

Fired it up this morning with the turbo action valve body. Reverse engages solidly.

Clark

Jack stands.is the absolute worst place to test an automatic transmission.

Reverse is the application of the forward (front) clutch and the rear band. High gear is the front and rear clutches both applied. The transbrake is engaged by putting the trans in reverse and high at the same time (forward, direct and rear band at the same time).

On a nonLBA valve body, the 1-2 shift is not easily felt on the stands unless you're dragging the brakes.

If the transbrake engaged, and reverse did as well, I would have checked pressures or just taken it to the track to try and not paid a ton of attention to how it "felt" on the stands.

I would also expect to see some overlap on the 2-3 on the stands, if it's timed right for a 6-7000RPM shift under load on the track.