1970 Roadrunner 727 Problem.

[TimS]

Time for line pressure test and possible an air pressure test of band servos and clutch packs.
Does the po know what was included in the trans rebuild?

Previous owner mentioned the stock converter was traded in for a rebuilt one. Also that there were new clutch packs and bands. He spoke of the clutch band material being something of a new product but I don't recall the difference between that and the original type. I'll ask him.

 

[wyrmrider]

transgo reprogramming kit will solve the drain back problem
My late buddy Gil Younger had a patent on his kit valve but it's run out and now most everyone has a copy of one in their kits
but I agree on the additional tests
rear clutch is the clue
you say manual low still is slow- should not make any difference as the one way sprag controls
If you get the transgo big reprogramming kit you get their tech hot line number- ask for Jim or Dave- I'm sure they would be interested in your problem and solution

 

[mopar 3 B]

transgo reprogramming kit will solve the drain back problem
My late buddy Gil Younger had a patent on his kit valve but it's run out and now most everyone has a copy of one in their kits
but I agree on the additional tests
rear clutch is the clue
you say manual low still is slow- should not make any difference as the one way sprag controls
If you get the transgo big reprogramming kit you get their tech hot line number- ask for Jim or Dave- I'm sure they would be interested in your problem and solution

Programing kit will be worthless if a shaft seal ring got broke during rebuild or an actuator is damaged and not working. He needs to find the problem before adding new parts?

 

[TimS]

Just got it home. It's really odd that it moves in reverse as normal but just won't move forward. If it weren't for the fact it also doesn't load the motor you would think it had a stuck brake.

 

[wyrmrider]

UH I said transgo kit would fix drainback problem
he needs to do the tests to help identify hard parts problems first
I'd give Transgo a call Monday or Tues- this is not a common problem

 

[dvw]

Just got it home. It's really odd that it moves in reverse as normal but just won't move forward. If it weren't for the fact it also doesn't load the motor you would think it had a stuck brake.

This is a a rear clutch circuit issue. From the valve body to the clutch itself fluid pressure is not holding the rear clutch. It is either hydraulic (piston seals, sealing rings, valve body issue) or clutch friction failure.
Doug

 

[miller]

Believe Doug is on the mark. Something in the rear clutch circuit.
Easy(?) way to check is, drop the pan and shift body, then do an air check. Should have been done while assemble was done. Too easy for a part to go in wrong, and screw up the works.

 

[TimS]

Just got it home. It's really odd that it moves in reverse as normal but just won't move forward. If it weren't for the fact it also doesn't load the motor you would think it had a stuck brake.

I shouldn't have said it doesn't move forward. It does, just very slowly for about 15 seconds then off it goes.

 

[miller]

Something like that won't fix itself...and, could be a handful of different things. Fix it now, or fix it later, after it gets worse. Your call.
Might consider at least changing the fluid and filter. Won't cure it...but, won't hurt it either.

 

[wyrmrider]

looking at my techtran manuals there is no specif symptom or check given for your symptoms- looks like you have excellent advice above- share what you find
pretty obvious the trans will have to come out but diagnose first- sometimes it's hard to spot a problem just looking at the parts, backwards seal, that kind of thing
air check etc
Sonnax has some good air check guidelines

 

[TimS]

Got the car purchased and home yesterday, off work today so I can play around with it. Previous two owners felt it was a tranny problem. I decided first thing to make sure it was the tranny not something else. It's a manual brake car so I pushed the brake pedal down w/o the car running. Put tranny in Neutral. Got out and pushed the car backward easily. Could not push the car forward at all. Long story short the left rear brake was dragging/stuck. Got into the brakes and loosened that side up just to see if that was it. It moves forward with ease now.
Thanks everyone. Got lucky on this one.

 

[mopar 3 B]

So much for the previous owners. Make sure the brake adjuster is functioning properly. They should only adjust in reverse while applying brakes. Brake pads were on correct with big shoe in back?

 

[TimS]

Yes big shoe is in back. I think I have a wheel cylinder issue.

Even though I'm not a Tranny expert I thought it very odd that the car was fine in Reverse. I know it's possible it could be the tranny though.

 

[TimS]

Still don't want to declare all good yet until I get it out on the road and the car shifts thru the gears. That was just in and out of the garage, but at least now it moves forward.

 

[dvw]

Got the car purchased and home yesterday, off work today so I can play around with it. Previous two owners felt it was a tranny problem. I decided first thing to make sure it was the tranny not something else. It's a manual brake car so I pushed the brake pedal down w/o the car running. Put tranny in Neutral. Got out and pushed the car backward easily. Could not push the car forward at all. Long story short the left rear brake was dragging/stuck. Got into the brakes and loosened that side up just to see if that was it. It moves forward with ease now.
Thanks everyone. Got lucky on this one.

I was under the impression from you that it didn't put any load against the engine. Was that incorrect?
Doug

 

[TimS]

I was under the impression from you that it didn't put any load against the engine. Was that incorrect?
Doug

Yes Doug I did say that in an earlier post. That's also why I don't want to get to ahead of myself declaring the brakes to be the whole issue. The car still does not go into gear forward as solid as my 6 barrel car does. For whatever reason as well, in Reverse, it seems more immediate and solid. This one feels like it sorta slides in. Pretty mushy for a tranny that was supposedly rebuilt.

Weather permitting I hope to get it out on the road and really try it out.

 

[TimS]

Got to really road test the car. Checked the fluid warm first and it was at the full mark as it should be. Running down the street, I noticed off the bat it would shift from 2nd to drive but no first. Even when I try to manually shift it down it doesn't shift. However the more your drive the car the more haywire the tranny gets. Got to where it would barley pull itself in drive. Drop it to second and it would at least move better. After driving up and down the road a bit and really getting it going around 50 MPH the tranny labored. Brought it back home and checked the fluid again. Strangely, it was halfway up the dipstick.

 

[wyrmrider]

no strange at all
fluid expands
check and adjust your fluid hot
but I doubt that the cause of your problems unless really foamy when you checked it

 

[TimS]

Normally checked cold, fluid will be at a high level on the stick. Not the other way around. Low cold, high hot. That's a hint to the problem, I would think.

 

[wyrmrider]

Sorry
I have the transgo shift kit so no drainback- anyway you check hot then when it's cold file a notch on your dipstick