rgoolsby70

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

00Silv4.8

iTrader: (10)

weird... I dont know if theres a separate clutch pack for reverse but there could be a seal that gave up?

how many miles?

rgoolsby70

about 120000.when it went out got in back up went forward then tried to backup and nothing

oldred95

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.

rgoolsby70

all forward gears work even if you pull it down to firstand go. you can manually shift them 1st thru 4th.only problem is reverse

00Silv4.8

iTrader: (10)

wow Im baffled then. I donno much about trans' other than I can smoke up in record time with stock trucks
I would say have someone drop it and run through it...

Good luck, let us know what it is

oldred95

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.

James B.

iTrader: (1)

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.

Howie54

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

MrHorsepowerLSx

iTrader: (13)

Proper fluid level? Best place to start