PaNaRaMuH

Hello guys. After a few drives of my rebuilt A4, I figured out I didn't have a 4th gear. After pulling the pan, I found a check ball in the bottom. Is there a check ball placement that would prevent a 3-4 shift? I haven't got it torn apart so I just figured I'd see if anyone knew.

Also, it has a Transgo HD2 kit installed and doesn't really shift firmly. Could this also be because of the check ball?

mrvedit

Most of the check ***** are designed to force fluid through a small hole when a clutch is applied to make it more gradual, but allow the clutch to release much more quickly. The 3rd accumulator check ball in the case is an exception; also one of the overrun clutch checkballs (which I don't understand.)

I'm no expert on this, but I don't think a missing check ball could cause a no-4th-gear condition. It might cause a slam into 4th gear.

Since you are going to have to drop the valve body to place the loose checkball, I would inspect the 4th accumulator very carefully. A cracked piston or assembly error could be your problem. Just about the only other reason would be a major leak or assembly error in the servo. Did you put a seal on the 4th gear piston and put it in the right way?

Concerning your soft shifts, did you also install a high-stall converter? That will make shifts feel much softer, especially if the after-shift rpm is below the stall speed (rpm).

If 1st, 2nd and 3rd gear work properly, that pretty much ensures that the guts of the trans are working properly. A missing 4th gear pretty much has to due to something wrong in the 4th accumulator, the servo or an electrical problem.

When you drop the pan, there is a hole in the case under the servo. This is 4th gear servo drain hole. You can apply air pressure with a rubber tipped blow gun to test that this applies the band.

I hope that helps guide you in the right direction.
Did you rebuild the trans youself? If yes, congratulations! If not, perhaps someone else should be fixing this for you.

PaNaRaMuH

TONS of great information here. I'll have to keep all of this in mind! I did in fact rebuild it myself. Thank you.

Concerning the soft shifts...I worded it wrong. Sorry about that. When it was running, at WOT it would not shift until I let out of it. Even then, it wasn't the shift that I was expecting with the trans shift kit.

Thanks for the swift reply.

mrvedit

Perhaps your PCM needs a tune to get the shift points right.
If you suspect something is slipping, measure the line pressure with a trans gauge. A trans pressure gauge is only $45 on ebay.
With the HD2 kit installed, you will see about 75 psi at idle in Park or Drive, 125+ psi at idle in Reverse, and when you blip the throttle values as high as 225. Significantly lower values would indicate a pump problem. (You remembered the o-ring inside the pump slide, right!)
If you have HP Tuners, the scanner will let you test the full range of line pressure.

I assume you probably want to get 4th gear debugged first.
Good luck!
And again, congratulations on getting this far!

PaNaRaMuH

How exactly would I measure the line pressure? I don't think anything is slipping...it pulled fine. I don't have HP tunners, though. :/ Need to get me that when I get more knowledgable about everything before I even start considering that road. I'll have a look at the 4th acc, though.

Thanks alot, will keep this updated.

mrvedit

Go to ebay and search for "trans pressure gauge kit". You want one with a long hose. There is a model 5550 for $39.99 plus $5.60 shipping.
It connects to the plug on the drivers side of the trans. The hose is long enough to reach your side window; I tie it to the mirror.
I do some test with the rear wheels off the ground, but also while driving to make sure my WOT shifts are at max pressure.
Hey, if you don't think anything is slipping, you might not need it, but it gives me confidence that the pump, pressure control solenoid and tune are working.