This is for the stock 4L80E in my 2001 Silverado. It is 2WD and currently has 188k on it as far as I know (I am not the original owner).

First off, this truck has recently become my DD again. It has sat rarely used, occasionally started and driven, in the past 2 years. Roughly 200 miles in that time. I bought it 5 years ago, and have had zero transmission problems to date. I believe the original owner has done a bit of towing with it, but I have only towed a couple times. I have never off-roaded it or abused it.

While driving around today, I noticed the engine revs going up, and me going nowhere. Then it would suddenly hit and I'd be off. At first I thought it was the tires spinning because it was wet out, but now I know it was not. The tranny started acting up, acting like it was slipping big time especially from a stop. I thought the linkage was off and popping it into neutral, but it wasn't. Putting it into all lower gears did nothing.

Finally, it gave out altogether and I had to be towed home. All forward gears and reverse are gone, the truck will not move under its own power. Strangely enough, if I let it sit for about 10 minutes, I'll get about 10 seconds of the tranny working, then absolutely nothing again. That's how I parked it after the tow truck dropped me off.

The fluid and filter have unknown miles on them, they were in it when I bought it. I know, I should have changed it before. Hindsight, etc. Anyway, the fluid was not low, and no visible leaks. The driveshaft was not turning, so I know it's not the rear end (not like I'm going to blow up a 14 bolt, but I digress). The shifter linkage has been confirmed to not be snapped.

After getting it home today, I pulled the supply line off the transmission cooler and started the engine, to check for fluid flow. It sprayed all over the place, so the pump seems to be working (possibly intermittently?). I dropped the pan, and found no chunks or metal shavings. The fluid still has a red tinge to it, not that black at all. It does not smell burnt.

Some of the fluid left in the pan. Doesn't look bad at all.



The magnet was attached to the filter near the pickup hole. It has no metal shavings on it, only a thin layer of sludge that wiped off easily enough.



Pan drained completely. The dots are just debris, doesn't look like anything sinister.



The stock filter media feels like rough sandpaper, looks like it's got quite a few miles on it (I've put at least 15k on it myself).

So, how screwed am I? Can I be lucky enough that it was a clogged filter, or is the pump done? I'm off to the parts store to get some fluid, already have a Wix filter and new gasket on hand.

 

Based on your pics, it looks like your clutches are gone. The black stuff in the pan is what is left of your clutches. I’m afraid it is time for a rebuild.

 

That doesn't seem consistent with all gears, including Reverse being lost at once.
Despite your test, I'm thinking a pump problem or major constriction.

Yes, regardless of what it exactly is, it does seem to require a rebuild.

 

We have seen the clutch debris clog the filter and cause a no movement situation. I think it's time as well.

-Brian

 

Yes what Circle-D_Brian said. The clutch debris clog up the filter and when you shut it off some of this debris will drain out of the filter. When you start it up and try it again it will only work for a very short time before the clutch debris clogs up the filter again. Changing filter and fluid now I feel would be a waste of money and time, that is a lot of clutch debris in that pan.

 

Just thought I'd update this. A filter and fluid change did solve the problem. All gears came immediately back and it was back to shifting like normal.

However, after prolonged driving on the freeway, it started to overheat. I lost OD and it started slipping in first gear, which is apparently part of the tuning to keep the tranny from overheating too much. Anyway, I figured I had some crap in the lines, so I flushed out the cooler lines and both transmission coolers. A bunch of nasty fluid came out of them, looked like maple syrup. Afterwards, I drove it for over an hour with no overheating.

I'm currently ordering a big aftermarket cooler and will change the filter and fluid again just to be safe, but I'm pretty happy to have my truck back and driving around again. Hopefully this info will help others.

 

All too often people giving advice may choose the worst case scenario by giving an easy answer such as "you need a new transmission....esoecially since they aren't gonna dish out the money for the replacement. But you my friend were smart enough to diagnose the problem and perform Process of Elimination via a much cheaper and easier route by changing your filter and fluid. Other common problems on the 4L80e transmission incluse the shift solenoids, TCC solenoid, and leaking internal wire harness connector.

 

I think a can of kooler Kleen and a filter and fluid is generally the first step in any transmission problem diagnostic.

but the cooler being full of schmoo begs the question....where did it come from? i would guess the converter lock up clutch.

I personally would eliminate the TCC PWM programming and just have it function like an on/off switch.

190k is about the average lifespan, so plan on a refresh at some point. probably wise to calibrate the dipstick next time you have the pan off...the stock ones are notorious for reading full when they are actually 2-3 qts low.

 

You do realize that you are replying to an 8 year old thread dug up by a bot, right?

 

nope totally missed that lol. using this forum on mobile is super clunky. I do wonder how long that dude's transmission lasted tho. I'll leave my comment as it's still relevant and useful

 

How do you calibrate the dipstick? I just installed a used 4l80e and am really hoping I lost all gears cause the dipstick is inaccurate.

 

It is very unlikely you lost all due to a dipstick error, But the way I do it is with pan off dipstick installed mark stick at pan rail.
Here is the issue with a used 4L80E THEY ARE OLD, No one throws away a 70k plus truck till it's beyond done, They are many times in commercial vehicles and used abused with little if and services done.
I always tell people the odds at this point of getting a GOOD USED 4L80E are nill . Unless you are lucky enough to find one that was recently properly rebuilt or from a low milage wreck that has been sitting many years .