4l80e no reverse
#1
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4l80e no reverse
I HAVE A 1998 CHEVY PK 3/4 TON
WITH A 454 AND 4L80E TRANNY
ALL OTHER GEARS WORKING BUT
REVERSE WILL NOT WORK
HAD NO PROBLEMS WITH REVERSE PRIOR...JUST STOPPED
I'V ALREADY DROPPED THE OIL PAN..NO SIGNS OF METAL SHAVINGS OR VISABLE DAMAGE
UNABLE TO FIGURE OUT WHAT IS GOING ON WITH THE REVERSE
CAN SOMEONE PLEASE ASSIST ....
THANKS
WITH A 454 AND 4L80E TRANNY
ALL OTHER GEARS WORKING BUT
REVERSE WILL NOT WORK
HAD NO PROBLEMS WITH REVERSE PRIOR...JUST STOPPED
I'V ALREADY DROPPED THE OIL PAN..NO SIGNS OF METAL SHAVINGS OR VISABLE DAMAGE
UNABLE TO FIGURE OUT WHAT IS GOING ON WITH THE REVERSE
CAN SOMEONE PLEASE ASSIST ....
THANKS
#4
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Looks like the only apply device that could fail and not effect the forward gears is the Low Reverse band which is located in the rear of the transmission. Going by the range reference chart you SHOULD NOT have manual first gear either. Meaning if you pull the shifter down to 1st it should not move if it is the Low Reverse band that has failed in some way. If that is the case its probably something like an anchor pin/bolt or something in that fluid circuit for the servo causing the problem.
Last edited by oldred95; 07-26-2009 at 07:40 PM.
#7
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I put an 80E in a 03 truck the first of the year because of this exact same problem. It was pushing 200k miles and the guy just wanted a GM reman with warranty and be done with it. It had the exact same problem. Just no reverse. Its got to be something in the fluid circuit then that puts fluid to the low reverse band servo when in reverse. I know there is a "reverse" check ball. Possibly an issue there? Maybe blow through the seperator plate? I hope mine doesn't do this.
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#8
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You don't need the rear band for any forward gears. In manual low it only prevents overrun. So, if the band broke all forward ranges would still work identically in "D". Still could be that band, and breaking them is not uncommon especially in trucks that experience a lot of "Reverse" during a forward roll, not saying that happened.
Here's the fun part: getting to that band requires removal of literally the entire rest of the transmission to get to.
Here's the fun part: getting to that band requires removal of literally the entire rest of the transmission to get to.
#9
Hi .I know this is an old thread but I have a similar problem with a 4L80 in a 1994 National RV motorhome. shift into drive and it feels as if it goes in but no drive and no reverse .unplug the connector on the gearbox and I think it goes into limp mode as it does drive but still no reverse. Thinking a will have to pull the box out. Would be grateful for any ideas. Thanks