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No reverse in '95 K2500 Suburban with 4L80e

95Burbnc

95Burbnc

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Messages
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Location
Hays, NC
Over the past 2 months, I noticed my Suburban was slipping into reverse more and more. 190K on it by the way but only about 14K on the rebuilt 6.5TD. Now reverse is completely gone. The forward gears / OD work fine with no slipping and I even pulled my camper last weekend (it was a bear to back the truck up to hitch it!)
The local transmission shop checked it out and said the fluid level was fine and it doesn't smell burnt. He recommended a full rebuild though with "the upgrades" - whatever that means - $2000 was his estimate. I guess he really doesn't want to work on it.
I've looked through the threads here and found tranny issues with reverse + OD but my problem seems different and the fact that it slowly lost reverse to increased slippage over the past couple months makes me think it is a different problem.
Is there a good troubleshooting FAQ for the 4L80e on the net - or does anyone have some experience with a similar problem?
Currently I'm looking for a junkyard transmission to swap it out with unless I can find a way to troubleshoot this one.
Thanks for your help!
 
Cracked reverse input drum would be my guess. This is a fairly common issue with early 4L80E trans due to pressure spikes from the early pressure regulator boost valve. Whatever route you go, make sure and put a TRANSFO SK or HD2 shift kit in to upgrade the trans and prevent this from happening again. And $2K for a full build is not that bad if they are doing all clutches, steels, torque converter, and electrical. I get that much out of my house for doing em as I will have close to $1500 in just parts to do one my way.
 
Thank you so much for the info about what this problem could be and what to look for and to upgrade if we go with rebuilding this one. Also I really appreciate you confirming that the estimate is not that far off for a quality rebuild. My local shop is well respected and they've done work for me before. I think my comment earlier was from sticker shock!
 
Before you do anything else drop the pan and make sure the reverse servo isnt cracked, Its a common problem with 4L80E's and you will lose reverse when it goes, Wait I see you said it was gradual if thats the case when you drop the reverse servo, Take the pin to someone that does tig welding Lengthen the reverse servo pin about .200 where it engages with the Band, make sure you radius the end, then heat it red hot and imerse it in oil to harden it, More likely than not it will take care of your problem
 
Cool! We'll give it a try. Good to hear from you neighbor!! Let me tell you again how much I like your wiring kits!! The batt cables and the glow plug harness have worked great and the terrific personal service you gave me could not be beat! Worth every penny!! Thanks for the tranny help!
Mike
 
95Burbnc said:
Cool! We'll give it a try. Good to hear from you neighbor!! Let me tell you again how much I like your wiring kits!! The batt cables and the glow plug harness have worked great and the terrific personal service you gave me could not be beat! Worth every penny!! Thanks for the tranny help!
Mike
Click to expand...

Well Thank you I certainly appreciate the Kind words, and I hope that turns out to be the problem it will buy you 10-20k more miles out of your trans
 
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