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Auto trans won't back up? #1092809
10/11/11 05:07 PM
10/11/11 05:07 PM
Joined: Dec 2004
Posts: 2,703
Mohnton, Pa
DodgeCharger Offline OP
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DodgeCharger  Offline OP
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Mohnton, Pa
I have a 727 foward manual valve body with low band apply. It was working fine for a few hundred miles.
I parked it and went to back up and the car wouldn't move. All forward gears work fine. I ran the car on jackstands. Forward gears fine. In reverse the tires won't move and it pulls the motor down when I give it slight throttle.
Any Idea what might be the problem? Is it the valve body or something bigger? I am thinking something left loose in the modified valve body causing it to work like a trans brake.
Any ideas would be appreciated.
Thanks,

Re: Auto trans won't back up? [Re: DodgeCharger] #1092810
10/11/11 05:15 PM
10/11/11 05:15 PM
Joined: Jul 2010
Posts: 224
in the middle
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dodger mope Offline
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in the middle
the rear clutch plates are welded together

Re: Auto trans won't back up? [Re: dodger mope] #1092811
10/11/11 05:18 PM
10/11/11 05:18 PM
Joined: Jan 2008
Posts: 350
Sidney,Ohio
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challenger1320 Offline
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Posts: 350
Sidney,Ohio
I would say it pushed the piston seal out and has the clutch pack locked up

Re: Auto trans won't back up? [Re: challenger1320] #1092812
10/11/11 06:13 PM
10/11/11 06:13 PM
Joined: Dec 2009
Posts: 20,622
in a cattle trailer down by th...
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Guitar Jones Offline
Paddle faster! I hear banjo music!
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in a cattle trailer down by th...
If it drives in neutral the rear clutches are locked up.


"Follow me the wise man said, but he walked behind"


'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost coming soon!
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
Re: Auto trans won't back up? [Re: Guitar Jones] #1092813
10/11/11 06:19 PM
10/11/11 06:19 PM
Joined: Dec 2004
Posts: 2,703
Mohnton, Pa
DodgeCharger Offline OP
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Mohnton, Pa
How does that happen?

Re: Auto trans won't back up? [Re: DodgeCharger] #1092814
10/12/11 09:24 AM
10/12/11 09:24 AM
Joined: Jan 2008
Posts: 350
Sidney,Ohio
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challenger1320 Offline
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Sidney,Ohio
What I said. Is how it happens

Re: Auto trans won't back up? [Re: DodgeCharger] #1092815
10/12/11 09:36 AM
10/12/11 09:36 AM
Joined: Dec 2009
Posts: 20,622
in a cattle trailer down by th...
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Guitar Jones Offline
Paddle faster! I hear banjo music!
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Joined: Dec 2009
Posts: 20,622
in a cattle trailer down by th...
Quote:

How does that happen?




I have also seen the rear clutches welded together from slipping. Using the transmission instead of the brake pedal when going from reverse to drive will eventually wear the rear clutch discs until they start slipping all the time and will then eventually weld themselves together.


"Follow me the wise man said, but he walked behind"


'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost coming soon!
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
Re: Auto trans won't back up? [Re: Guitar Jones] #1092816
10/12/11 12:56 PM
10/12/11 12:56 PM
Joined: Jul 2008
Posts: 30,424
Florida STAYcation
dOc ! Offline
The village idiot's idiot
dOc !  Offline
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Posts: 30,424
Florida STAYcation
PROBABLY the "spring" has flipped-over and locked the clutches up. From what I Have seen .. if the clutches are welded-up due to slippage ... the ATF has been toasted.

Re: Auto trans won't back up? [Re: dOc !] #1092817
10/12/11 01:03 PM
10/12/11 01:03 PM
Joined: Mar 2009
Posts: 1,058
bigfork mn
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dragram440 Offline
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bigfork mn
I dont know much about automatic trans but on mine the lever that applies the band for reverse broke and I had all gears but no reverse. Mine was on a fresh trans so I dont know if something didnt get put together correctly. The first time I put it in reverse there was resistance with a little pop and then it was just like in neutral when in reverse.


67' charger 499 RB 10.57 at 127
Re: Auto trans won't back up? [Re: DodgeCharger] #1092818
10/12/11 02:50 PM
10/12/11 02:50 PM
Joined: Jan 2003
Posts: 25,720
Rio Linda, CA
John_Kunkel Offline
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John_Kunkel  Offline
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Rio Linda, CA
Quote:

How does that happen?




In cases where the piston overtravels and pops out of its bore it's usually any one or a combination of things:
Weak Belleville
High Line pressure
No accumulator spring


The INTERNET, the MISinformation superhighway
Re: Auto trans won't back up? [Re: John_Kunkel] #1092819
10/12/11 10:47 PM
10/12/11 10:47 PM
Joined: Aug 2003
Posts: 2,401
Tucson, Arizona
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MRMOPAR Offline
top fuel
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Joined: Aug 2003
Posts: 2,401
Tucson, Arizona
Quote:

I dont know much about automatic trans but on mine the lever that applies the band for reverse broke






Low/Reverse band, strut, or servo failure.


68 RR 528" INDY MAXX 07 2500 CTD Southwest International Raceway - IHRA - Tucson, AZ
Re: Auto trans won't back up? [Re: MRMOPAR] #1092820
10/13/11 07:20 AM
10/13/11 07:20 AM
Joined: Dec 2009
Posts: 20,622
in a cattle trailer down by th...
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Guitar Jones Offline
Paddle faster! I hear banjo music!
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Joined: Dec 2009
Posts: 20,622
in a cattle trailer down by th...
Quote:

Quote:

I dont know much about automatic trans but on mine the lever that applies the band for reverse broke






Low/Reverse band, strut, or servo failure.




If this was the case it shouldn't pull the engine down liked it's locked up. It would just act like high gear. He also never said if it drives in neutral.


"Follow me the wise man said, but he walked behind"


'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost coming soon!
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
Re: Auto trans won't back up? [Re: Guitar Jones] #1092821
10/13/11 10:35 PM
10/13/11 10:35 PM
Joined: Dec 2004
Posts: 2,703
Mohnton, Pa
DodgeCharger Offline OP
master
DodgeCharger  Offline OP
master

Joined: Dec 2004
Posts: 2,703
Mohnton, Pa
Quote:

Quote:

Quote:

I dont know much about automatic trans but on mine the lever that applies the band for reverse broke






Low/Reverse band, strut, or servo failure.




If this was the case it shouldn't pull the engine down liked it's locked up. It would just act like high gear. He also never said if it drives in neutral.





It doesn't drive in neutral.

Re: Auto trans won't back up? [Re: DodgeCharger] #1092822
10/13/11 11:01 PM
10/13/11 11:01 PM
Joined: Jan 2003
Posts: 16,923
NC
440Jim Offline
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440Jim  Offline
I Live Here

Joined: Jan 2003
Posts: 16,923
NC
Quote:

Quote:

Quote:

Quote:

I dont know much about automatic trans but on mine the lever that applies the band for reverse broke






Low/Reverse band, strut, or servo failure.




If this was the case it shouldn't pull the engine down liked it's locked up. It would just act like high gear. He also never said if it drives in neutral.





It doesn't drive in neutral.


If it doesn't creep in neutral, then I think the rear servo, band, or strut. You should be able to see it just by dropping the pan. You should have smooth action pulling on the rear servo by hand and watching the linkage engage the band.

Re: Auto trans won't back up? [Re: 440Jim] #1092823
10/14/11 07:09 AM
10/14/11 07:09 AM
Joined: Dec 2004
Posts: 2,703
Mohnton, Pa
DodgeCharger Offline OP
master
DodgeCharger  Offline OP
master

Joined: Dec 2004
Posts: 2,703
Mohnton, Pa
Quote:

Quote:

Quote:

Quote:

Quote:

I dont know much about automatic trans but on mine the lever that applies the band for reverse broke






Low/Reverse band, strut, or servo failure.




If this was the case it shouldn't pull the engine down liked it's locked up. It would just act like high gear. He also never said if it drives in neutral.





It doesn't drive in neutral.


If it doesn't creep in neutral, then I think the rear servo, band, or strut. You should be able to see it just by dropping the pan. You should have smooth action pulling on the rear servo by hand and watching the linkage engage the band.




I'm sorry I missunderstood you. It most likely creeps in neutral. On jackstands the tires spin in neutral without the brakes applied. I thought you meant drives the car in neutral. Even when the trans was working ok it would creep if you rev it up in neutral. I was told it was a tight clutch pack and nothing to worry about?







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