Coupler end play?

[tinbanger]

Well I pulled the trans out for a yearly look. My coupler was pushed 1/4 " into support.I was running 3/16" end play. The motor plate is not bent. My question is how much end play is to much? Any info would be a greet help.

[Mrs Esterhouse]

1) T
HE COUPLER MUST BE LONG ENOUGH THAT THE GROUND SURFACE IS COMPLETELY THROUGH THE BUSHING IN THE TRANSMISSION TAIL HOUS
-
ING
.  I
F THIS CANNOT BE OBTAINED IT WILL BE NECESSARY TO GO TO A DRIVE SHAFT WITH
4
COUPLERS AND A SPLINED DRIVESHAFT
.
2) I
N ORDER TO KEEP THE COUPLER PROPERLY ENGAGED IN DIFFERENTIAL COUPLER IT IS NECESSARY TO HAVE A SPACER INSERTED IN TO THE
COUPLER BEFORE INSTALLING IN THE TRANSMISSION
.  T
HE SPACER NEEDS TO BE A LENGTH THAT WILL ALLOW APPROXIMATELY
1/8”
OF MOVEMENT
OF THE COUPLER IN AND OUT
.  T
HIS MOVEMENT IS NECESSARY BECAUSE OF NORMAL MOVEMENT OF THE CHASSIS
. T
HE SPACER CAN BE MADE
FROM ALUMINUM
,
HARDWOOD OR PLASTIC
(
NOT SUPPLIED BY
M/W)
ROUND MATERIAL
.
3) A
LIGNMENT IS CRITICAL
,
ANY ABNORMAL WEAR IS A SIGN THAT THE ENGINE
-
TRANSMISSION
-
REAR PINION CENTERLINE ARE NOT PERFECTLY
ALIGNED
.  C
OUPLERS ARE NOT DESIGNED TO TAKE ANY MISALIGNMENT
.

[Mrs Esterhouse]

sorry that was a terrible post

[GlennLever]

sorry that was a terrible post

You can go back and edit your post at anytime to clean it up.

[tinbanger]

If I put a spacer in front of the coupler would that remove end play ? I had 3/16 play for flex.

[fuel749]

Are you saying that the coupler was into the trans bearing support? If that's the case, there's only a couple ways it can happen that I can think of.

The pinion is walking out. This could happen due to improper assembly or pinion bearings going bad. I kind of think you'd notice it.

The engine/trans moving back on the launch (or staying still while the car moves around it depending on how you look at it). If there's nothing limiting the fore/aft movement, the motor plate flexes and could cause a problem like that. Seems like it would have to go a long ways to take up that much slack and put the coupler into the bearing support that far. If your front engine mounts are floating saddles, look for witness marks where they've been sliding as the rear plate flexes.

[GlennLever]

I have a shorty power-glide, so no back support.

When I took it apart I found the the coupler that goes into the transmission had worn a grove into the plate on the rear of the transmission.

I have 3/16 of slop in the drive train (coupler on the rear end, coupler on the transmission and drive shaft between the two)

I have blow back tubes on the rear motor plate so I do not think the engine is moving back on the launch.

Talked to several people and the consensuses was that at the top end when under deceleration the whole drive train (coupler on the rear end, coupler on the transmission and drive shaft between the two) is being thrown forward into the rear plate on the transmission?

[Van]

Slipping a plastic or wood dowel inside the trans coupler as suggested works great. I really like a soft plastic dowel.   

[tinbanger]

My problem is the same as Glen's. There is no sign of movement near frame saddles. Pinion is we're it is supposed to be. What did you do about front travel during deceleration?

[GlennLever]

I will be replacing the bearing support. I know of no other fix, this wear was after 5 years of running the dragster

[Van]

My problem is the same as Glen's. There is no sign of movement near frame saddles. Pinion is we're it is supposed to be. What did you do about front travel during deceleration?

 To stop front travel - drop a piece of round plastic (Delran or nylon) inside the trans coupler, this uses the end of the trans shaft and the inside of the coupler to stop forward movement. I have made them a tight fit so they engage the splines when lightly driven in. Even a hole saw and an old car tire will make one. No rocket science needed.

[arush]

Don't mean to high jack this thread but I am in the process of doing this to my build and have a question. I have the male and female couplers installed and inserted an aluminum spacer to allow for 3/16" play.
With everything installed should I be able to move the male couple back and forth easily? When I slide it, there seems to be more of a drag on it than just the tension of the tranny seal. I may just need to fine tune the alignment.

[dreracecar]

If you are able to slide it at all you are fine, if you have to tap or pry, then you have to shim the motor plate.
At the hit everything twist and moves a great deal anyway, thats why you should never run a rear tranny mount. Final adjustment should be done when car is complete and the frame loaded on the ground. It only takes a few thou to start to bind things

[arush]

Appreciate your response Bruce.