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Old 12-03-2007, 11:12 AM   #1 (permalink)
Deere3594
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4L80- Goes forward in reverse or neutral

I have a 1994 6.5 1ton with the 4L80. If I put it in reverse or neutral it goes forward, like it is in drive. I still have forward movement in OD, D, 2nd, and 1st. "Park" works as normal I have checked the linkage, all that looks fine. I have also changed the fluid. Is it shot or anyone have any ideas? I hope I didn't miss anything searching on here. Thank you for reading!
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Old 12-04-2007, 06:44 PM   #2 (permalink)
GenBiltstein
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How long have you had the truck?
What have you done to the truck?
Check the connection going into the transmission, is it oily, contaminated?
Did anyone change any wiring going into the transmission?
Did anyone adjust or muck around with any physical linkage adjustments going to the transmission?
Did you run over any branches that mught have any affect to the linkages? Take a look.
How long has this problem been going on?
Isolate this problem is it electrical? is it mechanical linkage?
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Old 12-04-2007, 11:17 PM   #3 (permalink)
Deere3594
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How long have you had the truck? ABOUT 2 YEARS
What have you done to the truck? NOTHIGN WITH THE TRANS, LOTS OF STUFF TO THE MOTOR -IP, GLOW PLUGS, INJECTERS ECT..
Check the connection going into the transmission, is it oily, contaminated? CHECK THEM, THEY WERNT BAD, I UH PLUGED THEM, AND REPLUGED THEM...
Did anyone change any wiring going into the transmission? NO
Did anyone adjust or muck around with any physical linkage adjustments going to the transmission? NO, HAVE LOOKED AT IT WELL HAVING SOMEONE ELSE 'SHIFTING' IT, ALL LOOKS FINE/NORMAL.
Did you run over any branches that might have any affect to the linkages? Take a look.-NOTHING THAT I CAN SEE..AND DIDNT HIT OR GO THREW ANYTHANG OFF ROAD FOR AT LEST 6WEEKS BEFORE HAND
How long has this problem been going on? RIGHT BEFORE I PARKED IT TO CHANGE THE IP, WENT TO BACK OUT OF WORK AND IT WOULDNT MOVE, WENT TO PULL IT WITH A LARGE FRONT END LOADER AND IT STARTED TO DRAG IT, HAD TO USE THE T-CASE IN NEUTRAL TO GO BACKWARS...
Isolate this problem is it electrical? is it mechanical linkage? IM AM GUESSING ELECTICAL, AS THE LINKAGE ALL SEEMS "NORMAL"

Thank you for your reply GenBiltstein, I hope I answer your Q's ok..
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Old 12-06-2007, 02:16 PM   #4 (permalink)
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Sounds like it is locked up. How long ago did you drop the pan>??? Any debris inside>???
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Old 12-06-2007, 02:33 PM   #5 (permalink)
Deere3594
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nothing large that caught my eye, it has been some time though,, the truck has been sitting for a fhew months now
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Old 12-06-2007, 03:11 PM   #6 (permalink)
Mike L.
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Make sure the linkage on the side of trans moves along with shifter cable movement. If that's ok then drop pan and check linkage to manual valve and make sure when you manually move lever on trans that the valve moves with it. If that's ok, you may have a busted thimble filter behind the plug on the manual valve.

Last edited by Mike L.; 12-06-2007 at 03:11 PM.
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Old 12-06-2007, 10:11 PM   #7 (permalink)
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For some reason it never popped into my head but yes, make sure the manual valve moves with the linkage. I have seen things break or come undone and the manual valve gets stuck in a forward position. Does it feel like it wants to lunge forward when you put it in park>??? -Mat-
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Old 12-07-2007, 12:12 PM   #8 (permalink)
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"Does it feel like it wants to lunge forward when you put it in park>??? -Mat-"
Yes it dose!
My truck dosnt have a cable, its all "metal rods", for lack of a better term, from the firewall to the trans...
I hate to ask stupid Questions, but what is a "manual valve"? Maybe it will make sence when I get under it and look...
Thanks for all of your replys guys!!
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Old 12-07-2007, 08:42 PM   #9 (permalink)
GenBiltstein
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OK let's walk backwards a bit. You changed the Injector pump. Good start from there. Do not blame anything else. Misadjusted kickdown switch of some sorts. Check any sort of linkage going to the IP on the left side. Any wires. Most of the time I ever trouble shoot equipment it's 85% nut behind the wheel? If you realize thet one first you save big dollars.
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Old 12-07-2007, 11:17 PM   #10 (permalink)
Deere3594
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Quote:
Originally Posted by GenBiltstein View Post
OK let's walk backwards a bit. You changed the Injector pump. Good start from there. Do not blame anything else. Misadjusted kickdown switch of some sorts. Check any sort of linkage going to the IP on the left side. Any wires. Most of the time I ever trouble shoot equipment it's 85% nut behind the wheel? If you realize thet one first you save big dollars.
My pump doesn't have any linkage on/ near it. I will double check to make sure all the plugs are tight. Where is the kickdown swithc located at on a 6.5? Also, just to clarify, the trans started this before I changed the pump, if that matters or not..

And what nut behind the wheel?!
thanks you for your reply!
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