trans-brake in park and reverse

[Adam Whitman]

I just had the front pump apart for a new bushing. Had the regulator apart and can't see where I assembled anything wrong, but...something stuck?

When in Park and Reverse it loads the engine like it is in gear but there is no driveshaft movement. Revving it drags the engine down like there is a trans-brake on.

In Neutral and D321 it wants to go forward by looking at the turning output shaft (waiting on driveshaft to be built). Engine free-revs like normal.

If you have it in neutral the output shaft is spinning (freewheeling I assume) and then put it in reverse the output shaft stops. But if you then shift into park you can hear the park pawl grinding like something is still spinning in there.

I can't say how it worked before I got it but know that it drove into the shop and was replaced with a TH400 along with an engine swap.

Help?

 

[SSedan64]

I just had the front pump apart for a new bushing. Had the regulator apart and can't see where I assembled anything wrong, but...something stuck?

When in Park and Reverse it loads the engine like it is in gear but there is no driveshaft movement. Revving it drags the engine down like there is a trans-brake on.

In Neutral and D321 it wants to go forward by looking at the turning output shaft (waiting on driveshaft to be built). Engine free-revs like normal.

If you have it in neutral the output shaft is spinning (freewheeling I assume) and then put it in reverse the output shaft stops. But if you then shift into park you can hear the park pawl grinding like something is still spinning in there.

I can't say how it worked before I got it but know that it drove into the shop and was replaced with a TH400 along with an engine swap.

Help?

I'm no expert but, I'll take a stab.
Possibly the TCC Valve is stuck causing the binding.
The Trans Output will turn while in while in Neutral with no Driveshaft connected. Maybe someone will chime in with better Info.

 

[Adam Whitman]

I'm hoping you mean the external solenoid/valve at the bottom of the pump. Praying.... Engine had to come out for the trans to come out.

Anything to test other than replace the TCC valve.

OK, I'm getting it. Park pawl locks it up when in park creating the bind, reverse gear does the same when in reverse. Makes sense at least with my not knowing what gets turned off and on within the rest of the trans while in park or reverse.

Hope I didn't hurt anything, just revved it up and held up the rpm enough to bind it a few times trying to figure out what was going on. Hate to have fried a brand new TCC too.

 

[mikestertwo]

If you hear grinding like the parking paw is engaging then the output shaft has to be turning. You shouldn't be running it without a driveshaft yoke on the output shaft. The yoke supports the output shaft and keeps it centered in the housing.

 

[Adam Whitman]

Got a yoke on it, just no driveshaft.

I assure you it's not turning. Maybe it's not the park pawl but I can't imagine what else it would be to make that noise, and only when put in park after being in N or a forward gear, then shifted to reverse and then park.

If the TCC is locked, would it even idle if the output shaft isn't turning?

 

[Adam Whitman]

Aw crud, just read via search that it could be the o-ring on the input shaft (Is that right?) Just installed this converter and it went on a little bit hard but not horrible (no hammers involved, but a boot).

Or, the valve is stuck inside the pump. Damn I knew I should have taken that out of the pump too but decided to leave it alone. Does the control system hydraulically "un-apply" the clutch so if there is a leak the clutch is applied?

 

[SSedan64]

I'm hoping you mean the external solenoid/valve at the bottom of the pump. Praying.... Engine had to come out for the trans to come out.

Anything to test other than replace the TCC valve.

Yes, the Apply Valve under the Solenoid>> http://www.sonnax.com/system/assets/3331/original/77805-K.pdf?1289884077

I'm not sure if a Shaft Seal or Pump Gasket could also cause this. Here's a Lockup Diagram to look at, may help.>> http://www.turbobuick.com/forums/transmission-talk/260404-lockup-solenoid-tutorial.html

 

[Adam Whitman]

Yes, the Apply Valve under the Solenoid>> http://www.sonnax.com/system/assets/3331/original/77805-K.pdf?1289884077

I'm not sure if a Shaft Seal or Pump Gasket could also cause this. Here's a Lockup Diagram to look at, may help.>> http://www.turbobuick.com/forums/transmission-talk/260404-lockup-solenoid-tutorial.html

Outstanding! Sometimes I need help with searches too I guess. I was coming up mostly empty though still looking. Just printed flow diagrams for studying...

Ugh! I want to go to the bar. Thinking of ATF in my hair very soon...

 

[SSedan64]

^^^ Hair Tonic.

I remember reading about the Input Shaft seal also now that you mentioned it.

What was the problem with the TC install?
Should feel/hear 3 clicks, while rotating & pushing in on it. Input Shaft, Stator Support and Pump splines/Lugs engaging.

Yes, Hydraulic apply & un-apply.

 

[Adam Whitman]

^^^ Hair Tonic.

I remember reading about the Input Shaft seal also now that you mentioned it.

What was the problem with the TC install?
Should feel/hear 3 clicks, while rotating & pushing in on it. Input Shaft, Stator Support and Pump splines/Lugs engaging.

Yes, Hydraulic apply & un-apply.

I looked at the input o-ring and it looked and felt OK so didn't change it as I didn't have the exact replacement anyway.

The last 1/4 inch or less was 'tight." I don't think it was the pump, I suspect it was the stator support going on a little bit hard as it pulled back up to the flex plate kinda hard too. This is a new converter so that might reinforce the stator support idea too. Seems like I felt the clunk of the pump engaging.

 

[Adam Whitman]

OK, afer studying the diagrams it appears that if the TCC valve in the pump were stuck in the apply position that it would be stuck pressed in above the circlip that holds the valve assembly in; is that correct?

My TCC lockup valve is definitely flush against the retaining circlip.

This is making me think that I either have a bad o-ring on the input shaft, or the rebuilt converter has a dragging clutch. Has anyone ever had a rebuilt converter with a dragging clutch?

 

[SSedan64]

Yes, the TCC apply valve would be in/up position.

 

[Adam Whitman]

OK, and just to make sure I'm clear, this is visible by the plunger directly above the snap ring being pushed-up/compressed above the surface of the snap ring? I want to make sure that the valve isn't underneath a cap like with the PR.

 

[Adam Whitman]

after doing more searches it appears that the TCC solenoid bleeds pressure when off, so maybe it's plugged. However, when in low gear the valve body turns off oil flow to the TCC solenoid and valve.

So, if it doesn't lock in low, but all the other gears it is probably the TCC Solenoid plugged

If it locks in all gears including low it is probably the o-ring on the tip of the input shaft, the TCC valve itself is stuck (which I don't think is true), or...?

 

[Adam Whitman]

Not the TCC. Idles fine in any forward gear with the yoke locked in place with a bar since I have no driveshaft. Rev it and it loads normal-like for an automatic, as if it wants to go forward.

BUT:

It tries to go forward in all gears. Binds up in P and R, wants to go as if it were in gear while in N,D,3,2,1. I can't test drive it yet as the drive shaft isn't done.

I am thinking forward clutch is stuck and search function seems to concur. Yech. out she comes...


The TH400 is looking pretty good sitting there....

 

[chris718]

I bet when you put the pump in the other parts below it werent seated and you bound up the guts.Pull it out.

 

[Adam Whitman]

OK. When I get it out, how do I verify that I bound it up, and how do I fix it?

 

[87_we4]

Somethings wrong if you had to"boot" your tc on. It should slide on nice and easy

 

[clusolynn]

Binding?

Remove the pump from the transmission and inspect the large plastic thrust washer on the pump for correct position. If it looks okay, check the input shaft and overrun drum to verify they are seated correctly. If all you did was remove the pump, it shouldn't get any deeper than this, but...well, check those two things and let us know. Good luck, John.

 

[Adam Whitman]

Ehw, stinky fluid already. Not sure if I did it that quick just diagnosing or not, but it's cooked. I'm going to choose to believe right now that it already had a cooked forward clutch.

Will pull the front pump and have a look at the washer tomorrow.

Now back to deciding if the TH400 goes in or to hurrriedly get this thing rebuilt, and where, or do it myself. I'm afraid a trans shop won't give the proper attention to get this thing right without a couple more R&R's.

Wondering if I'm up to doing it myself with Chris's book. My local trans-guys keep telling me about some nightmare-to-get-right seal installs in there...