TF-727 Reverse Trouble

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JoJo

JoJo

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The reverse in my transmission decided to take a nap. I never had much of an issue before this matter. I can put it in reverse or neutral with engine off and push it back... With engine running, seems like everything is engaged/shifted forward for the drive position. I can put in reverse/neutral and it just sit there. I pulled the pan and discovered metal in the bottom of the pan. I don't know if a snap ring or what fell victim. All help is greatly appreciated.
 
Does manual low work? If not, it's probably the rear band and/or servo.
 
.............u could try adjusting the rear band, might help 4 awhile.....torque to 72 in lbs, then back off 2 turns...rear seal or servo may have broke/cracked......do u have 3rd gear, if not front clutches are fried......kim.........
 
if the forward gears are working...drop and pan and look for a rear servo malfunction...the servo might be cocked in the bore...or look at the rear band ....
 
Thanks for the information!

I will pull the pan back off and check the servo. Can I replace the servo while the transmission is still in or I'll have to cry for a few days and then remove it?
 
If you remove the valve body (isn't hard, unscrew the larger hex head bolts), you can test the servo by applying air pressure to one of the holes in the casting. The FSM and the tranny manual should detail the procedure. You should hear the servo piston move and see the rear band tighten. Check all the pistons while you are doing that.

However, hard to tell how tight it pulls, so either way you probably need to pull out the piston to make sure it hasn't cocked. That is an endemic problem and there is a better after-market aluminum piston improvement that costs <$20. You need snap-ring pliers to remove the piston. I don't remember if you must remove the valve body to get at it.
 
................U dont use snap ring pliers, u use a small flat blade screw driver........unhook ur shift linkage and levers off the vb, ...pull the pan, take out 10 vb bolts, drop down vb,may or may not be a spring over or under the accumulator... u will likely have to rotate the drive shaft to get out the park rod....loosen off the rear band lots......u will need 2 long screw drivers to get out the band strutt 1 to push the band away from the anchor and the other to pry/twist the strutt out.....push up on piston, pry out snap ring.......dont have ur head directly under it or u will get an atf bath.............kim.......
 
Thanks for the responses/information.

I haven't had the opportunity to pull the pan back off just yet. I found a rear billet servo from Performance Automotive and Transmission Center at $19. Is there anything else needed in order to swap pistons?
 
JoJo said:
Thanks for the responses/information.

I haven't had the opportunity to pull the pan back off just yet. I found a rear billet servo from Performance Automotive and Transmission Center at $19. Is there anything else needed in order to swap pistons?
Click to expand...

Just a C-clamp and large socket to compress it a little so you can get the snap ring out. First I'd air pressure test it though to make sure it's the problem. Throwing parts at it in hopes of a repair isn't the proper way to do things. Also about that El-cheapo billet servo, if you do have to use it make absolutely certain that it fits good and tight. The cheap ones I've seen are sometimes made too small and can flip in the bore easier than a stock one.
 
if it goes forward in neutral one is out of luck. the forward clutch pack is welded together and will have to be rebuilt.
 
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