67' Dart GT /6 with all the go fast rigg'en. When I shift the old A 904 from park to drive, park to reverse, or reverse to drive there is a rather abrupt pounding of the drivetrain. As a side note I have been told the this transmission has a reverse valve body, so the gear selector goes P R N 1 2 D.

I discovered I can move the output shaft up and down by pushing up on the drive shaft, the rear seal is not leaking. Is this normal? Can the output shaft bushing be changed with out removing the transmission? Also there may be some play in the rear U joint, and I don't know if the rear brakes need adjusting. I have not driven this car on the road to see if there is any drivetrain vibrations.

I do not know what stall speed the converter is, or if it maters. Idle speed is not excessive, and trans fluid is at the proper level, and fresh looking.

Also could a bad engine mount cause this problem, and how would one check their condition?

A bad tranny mount... you can physically see your motor mounts from either fender and see if they are in OK shape...and with the sandwich mounts you can move them a bit with some muscle on the engine block...

I would also crawl under the car and inspect the tranny tailshaft mount and make sure 1) the 'block' of rubber is fairly intact, and 2) none of the bolts have wiggled loose and dropped out (one from the mount to the crossmember, and two in the tranny tailshaft...

If either the motor mounts or the tranny mount are 40 years old... it may be getting time to replace them...

-D.Idiot

D. I. I checked the center mount supporting the tail shaft, a 3/8" bolt, or something that size, oriented verticality was tight. I was unable to get a wrench on the other bolts holding that cross member to the frame . The car was lifted by a set of ramps under the rear wheels. In other words I couldn't fit under the dang thing.

I think I will have to get a second pair of eyes to view the engine, transmission, and U joints as the car is shifted in and out of D & R to see what is hopping around under there. Hopefully no mounts will bee needed.

If the selector has the reverse gear pattern and the trans responds to that, then yes, it has a special (race) reverse valve body. (VB)
Most all of these kits eliminate the use of throttle pressure (TP), does your set-up have any throttle pressure linkage or even a TP lever on the trans?

Basically, this set-up will always "hit hard" when put into gear.
Your options are:
-Keep the idle speed as low as possible.
-Turn down the transmission's main "line pressure".
-Avoid taking the car out of gear.
-Swap-out the valve body for something more "friendly".

A higher stall converter help reduce the hard hit (a little) but the bottomline, this is the way these VBs function.
If you are running a 7 1/4 rear end, it will not last long behind this VB.
DD

There is away to change the tail shaft bushing in the car, but it takes a special tool to pull the bushing. You can also remove the tailshaft housing with the trans still in the car, this is the way I changed out my tail shaft bushing. Once you get the tialshaft housing off you can just drive the bushing out. If the ujoints or rearend have a lot of play/slack they will make this feel a lot worse than it should be. Fix you ujoints first and go from there. ALso the trans mount, even though it may not be broken, they are bad about being collapsed and this will let the trans be setting metal to metal. This will make any noises or vibrations feel worse than they are.



As far as the racing valve body, I run these even in my daily drivers. They really should not make it go into gear harder, unless someone has turned the pressure regulator up on it, or the engine idles to high. NOw when it shifts gears hold on because it is going to hit vary hard if you shift at any kinda higher RPM. If you shift real quick at low RPM they can still shift pretty soft.

Chances are the noise is the ujoints because they are under much more pressure from the hard shifts (its probably wore them out). ANd if its the liittle rearend it may be getting sloppy for the same reasons. A 8 3/4 rear holds up real good with hard shifts like this. You should drive this car, you will feel a tranny that works like no other auto you have driven, probably. They are a very good setup and help the tranny work and last very good. The trade off is they put more pressure on drive train parts
( ujoints,rear end,ect,ect,ect) but IMHO its the only way to run a torqueflight trans. Although we do not make that much power with our slant six engine, when power does start getting made these valve bodys have helped keep trannys going when they could not hold up before. Plus they will make the car faster and more consistant. SO keep the valve body, fix what needs to be fix to work with it. Start off with your ujoints and trans mount replacment.


Jess