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"Flushing" Tranny for torque bind


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25 replies to this topic

#1 KRB64

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Posted 28 December 2013 - 09:32 AM

I'm following the advice of changing the tranny fluid a couple times to hopefully eliminate the bind. Question is how much should I drive between changes? Just long enough to get to operating temps and then drain and refill or should this happen several times first?

Thanks,



#2 johnceggleston

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Posted 28 December 2013 - 09:51 AM

just around the block, manually shifting the trans into all gears.

you just want to mix the old and new fluid.



#3 grossgary

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Posted 28 December 2013 - 10:05 AM

you can drive as long as you want- but yeah it really doesn't matter, just mixing the fluids.



#4 KRB64

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Posted 28 December 2013 - 12:50 PM

Thanks guys.



#5 KRB64

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Posted 29 December 2013 - 04:52 PM

What I drained out looked more like engine oil than tranny fluid. Just drained and refilled for the second time, will see what happens.

Thanks for the help.



#6 CNY_Dave

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Posted 30 December 2013 - 10:01 AM

If putting in the FWD fuse eliminated the bind the fluid changing has a shot at working...



#7 KRB64

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Posted 04 January 2014 - 07:23 AM

Well I've drained and refilled twice and it still comes & goes. May not be the cheap fix I was hoping for. Have enough DexronIII to do it one more time and see.

 

Subs are new to me and I have a tranny question. When I put it in Park it does like its supposed to but when I turn off the ignition it rolls a wee bit, just like I had the brakes on and let off. Is this normal?



#8 CNY_Dave

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Posted 06 January 2014 - 12:27 PM

That is a torque bind symptom.

 

Have you tried driving with the FWD fuse in with the fresh fluid to help flush the valve and solenoid?



#9 KRB64

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Posted 06 January 2014 - 01:15 PM

No, didn't realize that would help.

Many  thanks,



#10 Gloyale

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Posted 06 January 2014 - 01:34 PM

Well I've drained and refilled twice and it still comes & goes. May not be the cheap fix I was hoping for. Have enough DexronIII to do it one more time and see.

 

Subs are new to me and I have a tranny question. When I put it in Park it does like its supposed to but when I turn off the ignition it rolls a wee bit, just like I had the brakes on and let off. Is this normal?

 

You are still supposed to set the handbrake.

 

What you are feeling is the car rolling up against the "park" pawl in the trans.  This is a small tab of metal that engages the output drum of the trans.  It's not good to leave the whole load of the car on the pawl.  If it's a hill your parked on, you may have trouble taking it out of gear in the morning.  USE THE PARKING BRAKE......don't just leave it in park.

 

Also, since you have torque bind.....there is some stress holding in the drivetrain between front/rear until you turn off the engine.....killing the ATF pump pressure and letting the drivetrain "relax"

 

Between that and not using the handbrake that is the rolling your feeling.



#11 CNY_Dave

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Posted 06 January 2014 - 05:04 PM

When I had the wrong solenoid in my trans, when it was essentially locking up in park/neutral, it would lurch when I turned the key off. It is a very distinct lurch, completely seperate from not using the P brake on a hill.



#12 lmdew

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Posted 06 January 2014 - 06:35 PM

When I flush, I pull the radiator trans hose, drain and fill the trans and then start the car.  The trans will pump out about 3/4 of a gallon, shut off the car and fill the trans again.  Keep doing this until the fluid comes out clean.  On the second or third start I hold the brake and shift through the gears a couple of times.  Works great, pumps all the old stuff out first.



#13 KRB64

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Posted 07 January 2014 - 07:07 AM

Its a lurch like CNY Dave described and like the relaxing after no ATF pressure like Gloyale says. The button is stuck in on the brake lever for now.

 

Imdew - I flush my truck like that. But you don't mean that you refill the trans and then do it do you? I realize these are different beasts but I run the truck until the fluid stops then IMMEDIATELY shut it down. This empties the TC on the old Dodge.



#14 2Bigfish

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Posted 11 February 2014 - 01:27 AM

I had bad tourque bind on my 2005 Forester.  Changed ATF and used RedLine synthetic ATF.  It's way slippery'r than Dextron.  Tourque bind gone.



#15 CNY_Dave

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Posted 11 February 2014 - 11:43 AM

Lurch after turning the key off could be caused by the solenoid being bad or plugged or stuck (or same for the transfer valve itself) - that year, +12V fed to the solenoid releases the pressure, so if the solenoid does not work it locks the AWD.

 

That is less likely if the FWD fuse cures the problem- did the fuse have any effect?



#16 KRB64

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Posted 12 February 2014 - 05:53 AM

Yes & no. When I put the fuse in it doesn't always light up the dash light and cancel AWD. When it does, it does seem to eliminate the torque bind. But then again, when in AWD, the torque bind comes & goes anyway...



#17 CNY_Dave

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Posted 12 February 2014 - 10:55 AM

The light should come on even if the connections to the trans are severed, it sounds as though something more electrical and more general is amiss.

 

The fuse grounds a pin on the TCU, and carries almost no current whatsoever, the TCU senses the grounded pin and turns on the light and feeds +12V to the solenoid.

 

Could the TCU have a loose plug, or a wire loose in one of the plugs?



#18 KRB64

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Posted 13 February 2014 - 05:45 AM

Good point. I'll look at the wiring schematic and start checking connections, wires and grounds. What is the TCU by the way?

 

Is the solenoid in the tranny or mounted on the outside?



#19 johnceggleston

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Posted 13 February 2014 - 06:00 AM

if the FWD light comes on,

then the duty C is working.

if the FWD does not come,

on then the duty C is not working.

 

an intermittent duty c is not unheard of.

but i do not know the cause.



#20 lmdew

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Posted 13 February 2014 - 07:28 AM

From Above:  drain and fill the trans and then start the car.  The trans will pump out about 3/4 of a gallon, shut off the car and fill the trans again.

 

  1. drain and
  2. fill the trans and then start the car.  
  3. The trans will pump out about 3/4 of a gallon,
  4. shut off the car and
  5. fill the trans again.


#21 CNY_Dave

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Posted 13 February 2014 - 11:08 AM

I can say with all assurance the FWD light will tell you if the TCU thinks it is operating the duty-c, but it only says the TCU is receiving the signal to operate it.

 

If the duty-C is open or shorted the ATF temp light will flash and no FWD light, but the duty-c could be shot with the resistance not at either extreme end and the FWD light will illuminate.

 

So if the trans light is not coming on and the FWD light is intermittent, the one thing that's not causing the FWD light to be intermittent is the solenoid.

Doesn't mean the solenoid is good, though.



#22 CNY_Dave

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Posted 13 February 2014 - 11:09 AM

Good point. I'll look at the wiring schematic and start checking connections, wires and grounds. What is the TCU by the way?

 

Is the solenoid in the tranny or mounted on the outside?

 

The TCU is the Transmission Control Unit.

 

The solenoid and the valve are inside the tailshaft housing which is typically removed with the trans in the car.



#23 KRB64

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Posted 13 February 2014 - 05:06 PM

The ATF temp light flashes when first start it up. I assume that is just the check light like all the others though? Seems like it does it after all the other lights go off now that I think about it. But it doesn't stay on. I'll need to pay attention next time.



#24 lmdew

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Posted 13 February 2014 - 05:14 PM

Flashing 16 times after you start tells you there is a fault in the trans and the TCU has it in the memory.



#25 KRB64

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Posted 14 February 2014 - 05:33 AM

Thanks, I'll count. How does one access the TCU stored codes?






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