Tranny problem... what next!? Any advice!?

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Tripper

Older and more rusted every day!
Joined
May 10, 2007
Messages
14,153
Location
Central Tejas
Well, got everything goin'... motor runs good, elec fan's workin' so I was all set to break the motor in but now something new. After I filled the tranny (TH400) and start it up... it wants to go in Park & Neutral. Never had this happen B4 but it did set up for a coupe of years. Currently I have the rear end up on jack stands! Any advice would be welcome! [S

BoB
 
You're saying it wants to move in park and in neutral? That would be something internal, like the valve body or shift mechanism. The convertor shouldn't have that effect.

I think some of the little balls inside have maybe stuck from sitting or the trans was put together wrong. Did it work right the last time it was run? Since you have it up on jackstands try putting it into the other gears to see if it will "unstick" after it spins for a while and fluid gets circulated.

Don

Bob, I've given it a little thought and the ONLY thing I can see causing it is if the sector that is moved by the shift arm is not connected to the valve body. You think you are shifting gears but are not. Drop the pan and see if the sector in there is still connected to the valve body. There is a little pin in there that can break and it will seem like you are shifting but are not.

The reason I think this is because in park there is a dog that locks up the shaft, so if you were truly in park it could not move the driveshaft.
 
Is it possible?

Well, got everything goin'... motor runs good, elec fan's workin' so I was all set to break the motor in but now something new. After I filled the tranny (TH400) and start it up... it wants to go in Park & Neutral. Never had this happen B4 but it did set up for a coupe of years. Currently I have the rear end up on jack stands! Any advice would be welcome! [S

BoB

If the clutches packs were put in dry and it got any moisture in it, the clutch packs could be acting like they were engaged.....rust can form on the steels and lock them to the fibers..... just a thought... that way no matter where the selector was placed the forwards, directs and intermediates or even all of them could be engaged and acting like it was engaged..... Just a thought.... if the linkage was disconneted inside, the parking pawl wouldn't engage and it might roll even in park with the engine off..... if it locks in park (won't roll in park if you push on it) but you feel it trying to move the trans is appling the clutchs or the clutch packs are stuck together like I said above...... something to ponder....
 
Thanks guys, I'm gonna try & run the tranny a bit & shift gears to see if it will break free or even seems to be changing gears. Probably gonna talk to the guy who rebuilt it tomorrow!

BoB
 
One other thing I thought of...

if the end play is wrong (too tight) then everything could be bound up and turning inside even if the clutch's aren't applied or the valve body isn't leaking past or the linkage disconnected.... just another thought....
 
If the clutch parks are sticking together it shouldn't change gears in park and neutral even though it's wanting to move. If that's all it is it should break free after you drive it a little.
 
That will tell you if it is the linkage or not is if you find reverse. Even if the clutch packs are frozen it should still turn backwards if you put it in reverse. If there is no reverse, then I still am betting the internal part of the linkage is not doing it's thing.

Don
 
If it is really in park the drive shaft will be locked with no movement at all. If the wheels are turning while the engine is running and it is in park, then it could just be a shifter adjustment. Could the shift lever be on upside down? With the rear wheels off the ground, on stands. Get under the car and disconnect the shift rod or cable from the lever. Now move the lever and see if you can get the trans in park. The drive shaft will not turn if you get it in park.

I am betting the lever is on up side down and when the shifter is in park the trans is really in low gear.
 
If it is really in park the drive shaft will be locked with no movement at all. If the wheels are turning while the engine is running and it is in park, then it could just be a shifter adjustment. Could the shift lever be on upside down? With the rear wheels off the ground, on stands. Get under the car and disconnect the shift rod or cable from the lever. Now move the lever and see if you can get the trans in park. The drive shaft will not turn if you get it in park.

I am betting the lever is on up side down and when the shifter is in park the trans is really in low gear.

RPM,
Thanks, I'll try that too!

BoB
 
Hey Bob, inquiring minds want to know............what did you find out with your transmission?:)

Don,
Been tryin' to get my house finished so I haven't gotten around to it yet but the shifter doesn't seem to operate anything at all. I plan to disconnect the shifter & try to shift it manually. Also wondering if I have the shift arm backwards or something! I'll report back when I do! Thanks for asking!!!

BoB
 
Take the linkage off the trans and push the lever all the way to the front and turn the driveshaft it should lock when the park pin engages. If not try pulling the lever all the way back and turn the driveshaft again, If it locks then maybe the linkage is backwards.

Also you said the rear was up on jack stands. Sometimes the fluid will push the trans when there is no weight on it. But it should not do it in park unless the pin is broken or missing.
 
Arm should point up on a TH350 or 400, Bob. When you move the arm by hand you will still feel it clicking into different positions, but that doesn't mean anything, that is just that plate that has all the depressions cut into it clicking on a roller to act as detents. The pin is after that and you will have to drop the pan and watch to see if it is turning the rest of the shaft going into the valve body.

The heck with that house stuff, we have cars to get running here ! :D:D

Don
 
Hey Bob, inquiring minds want to know............what did you find out with your transmission?:)

The heck with that house stuff, we have cars to get running here ! :D:D

Don,
Well, looks like I might be moving into my new place by the end of next week so I'm back to finishing up my PU. I disconnected the shift arm & moved the arm up & lo & behold... I was able to get it into park. Really glad it was that simple & will work on getting that all straightened out now. Yipppeee!!! :D

BoB
 
Don't you hate it when you are thinking the worst and it turns out to be something so simple? :eek: I do that all the time, and forget to do the simple checks first.


Now put down that claw hammer and pick up the ball peen and get to work ! :D
Don
 

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