4l80e lost first gear and o/d

[Biggin0822]

Trans shop said that o/d slips and that causes it to shut down the “1st/ OD” solenoid. Anyone ever hear of anything like this? I put some Lucas oil trans slip stuff and it was fixed for about a week. Thought i was out of the woods because it would work fine until it warmed up (still does). So i figured a thicker fluid might just be the answer. It’s a 2001 4l80e with 37k miles on it. Trans shop thought that maybe because of low mileage some seals (solenoidK) aren’t sealing properly. Their only answer was a rebuild for $2200

 

[HotRodPC]

Sound like and I won't swear to it, but it sounds like what you're saying is it's gone into Limp mode. You pretty much have 2nd and Reverse and that's it. Is this behind and LS engine, you have a full powertrain computer or is it a stand alone controller?

 

[Biggin0822]

second third and 4th are ok. just no overdrive or first. I'll probably end up rebuilding it myself. Well, Youtube and I will do it. full computer from the donor truck.

 

[4WDKC]

look into the transgohd2 kit with your full rebuild, I am, the turbo ls guys say that kit in stock trans is good for 1k hp. No idea how true that is nor do I plan to find out but will be installing one in mine when the time comes.

 

[HotRodPC]

second third and 4th are ok. just no overdrive or first. I'll probably end up rebuilding it myself. Well, Youtube and I will do it. full computer from the donor truck.

There you go. Time to nut up and get **** done !!! You can do it.

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[Biggin0822]

Getting a parts list together to rebuild the tranny and I decided to pull the plug that goes to the transmission from the wiring harness (the big round plug)and re installed it. Also I made the coolant fan that’s right inline with the trans cooler run all the time that the truck is running. Also changed the trans tune to see if any of these may be a problem also. Doggonnit if i have had all my gears of tire shredding wonderment ever since! Must be 4 days now and I’m using it as a daily to see how long it goes and what makes the 1st and o/d problem re appear. Shrugs??