My 4L80E trouble codes

[Mogman]

That does not look good at all, the black is burnt fluid and clutch material

 

[Retiredwarhorses]

Ok, got the pan off. A member here confirmed I did need to take off the crossmember as did the TM when I checked that. The TM said remove the drain plug too though (there is not one [maybe 3L80?]). Supporting the transfer case with the floor jack.

Only metal dust on the magnet. Not seeing anything worrisome other than the fluid color and dirty filter, however I do not have much experience here.

What do you guys think? I have already ordered a new filter.

that’s the worst I’ve ever seen…..rebuild time.

 

[taskunitbruiser]

That does not look good at all, the black is burnt fluid and clutch material

that’s the worst I’ve ever seen…..rebuild time.

So not even worth refilling with new fluid and a filter in the off chance it was a plugged filter and just poorly maintained?

 

[taskunitbruiser]

Any recommendations on rebuild kits? Something with a great warranty and can handle diesel torque and heavy weight that will last.

 

[Mogman]

No body warrants a kit that I know of.

 

[Retiredwarhorses]

So not even worth refilling with new fluid and a filter in the off chance it was a plugged filter and just poorly maintained?

that black stuff is clutch plate and overheated transmission fluid…you can’t bring a transmission back from that.
That transmission is made for that truck, there are millions in circulation behind this same engine.
The diesel application uses a torque converter specifically for diesel engines for a lower stall speed.
The trans very well still works, just have to ask yourself how long….

 

[Retiredwarhorses]

Any recommendations on rebuild kits? Something with a great warranty and can handle diesel torque and heavy weight that will last.

You can have the best kit on the market, it’s the guy doing the work that makes all the difference, that and knowing how to apply the various upgrades and fixes to the transmission while it’s apart, that’s why I send all my transmissions out to a company here locally

 

[Mogman]

So not even worth refilling with new fluid and a filter in the off chance it was a plugged filter and just poorly maintained?

No it is toast, any decent transmission shop can build that transmission, there are literally millions of them on the road.

 

[taskunitbruiser]

I was told by a friend that the 4L80E came in both a 2wd and 4wd version and the 2wd will bolt up, but the gearing or something is different (he didn't know) and it won't work. Is this true?

Does this mean the torque converter is likely also toast? How can I tell?

 

[taskunitbruiser]

Also is it common for the up-armored Humvee's to burn up a transmission? Seems like the added weight and a 19 year old driving it could wear it fast.

 

[Mogman]

It common enough for any transmission to fail especially with a 19 year old at the wheel.
The 2wd and the 4wd have different output shafts, the first thing one puts into a transmission is the output shaft so a complete disassembly is required to change it.
I have actually seen much worse than what you are looking at, if it were me I would have that transmission rebuilt by a local shop, vet the shop looking at reviews, talk to the shop and make sure you are on the same page, you will save quite a bit if you pull the trans yourself, make sure to follow any instructions on flushing the cooler etc. the torque converter should be changed with the transmission, it also has a clutch in it that has been apparently abused, but the shop will require you to replace it anyway, they have them rebuilt so the cost is not too bad and that is a common enough converter that the shop you pick will not have any trouble getting one, yes the shop will require you to use a converter supplied by them.

You can go the mail order route but then you have to add shipping and any problems you may have are multiplied by the square root of the distance between you.

OR you can try to find a good pull out but I would only do that if you actually enjoy crawling under the truck and changing transmissions.

 

[taskunitbruiser]

I am calling a local transmission guy tomorrow. I am debating whether to call a flatbed tow truck, putting the transfer case in neutral and strapping it to my truck with my wife or someone in the Humvee, or dropping the thing out in my driveway and hauling it down. Leaning toward the tow truck! If the tow costs insane, I wonder if United Rentals has a winch on their rental trailers? I'll check that out. I still have this TPS wiring problem too, ugh.

 

[taskunitbruiser]

It common enough for any transmission to fail especially with a 19 year old at the wheel.

I get the odometer may be wrong, but it has 12k miles and little over 800 hours on the tach. Mostly hard ass military miles with armor I suppose.

 

[Mogman]

You can and should go ahead and troubleshoot that problem first if you plan on having a shop do all the work as they will not release the truck in that condition, the last I remember you are looking at a failed TCM.

You could go ahead and put a new filter and fluid in the transmission, it of course would not fix the 8x error codes but would allow you to get the TPS issue fixed and carefully drive it to the shop.

 

[Coug]

Might consider getting AAA+ towing. Will tow 100 miles or 200 miles depending on what level you buy. I do believe that towing to the shop would be covered.

 

[taskunitbruiser]

Update: I picked up the Humvee at the shop yesterday with the rebuilt transmission. The drive clutches were blown of course. Some parts were upgraded from stock. The guy said it was running good but was shifting late, said would be ok to drive home, but that I needed to get the TPS issue resolved. [He did not want to venture into unfamiliar waters doing that work].

I drive it home, the gym, and the parts store to pick up some electrical contact cleaner and it is shifting well (about 10 miles total). When I get home I sprayed the TPS connector really well with the cleaner to re-test it. I also disconnected the batteries to clear any codes. Now I get the 5V reference! I didnt have alligator clips or my wife home to press the throttle while I tested the variable voltage wire for the TPS. I decided to plug the connector back in (since I had to do that anyway to test the variable voltage) and test drive around the neighborhood. It shifted like complete #### and went into limp mode.

This morning I jumped the J2 and put it into diagnostic mode. It just does cycles of 12, which is normal. Tried to drive again and was out of limp mode but really late hard shifts, noisy/squeaking shifts, etc. #### basically, and I am very afraid to damage the transmission I just paid to be rebuilt. At this point I am thinking the TPS sensor is trash and maybe the TCM does better with no signal than a complete garbage signal. It isn't perfect and I have some anxiety pushing it up hills hard, but it is shifting much like it did when I picked it up from the shop (where sensor wire was unplugged). That was a relief. Picked one of my kids up from school in this setup and performed ok.

So I am quite sure the TPS is bad. Does anyone still think my TCM is bad? Seems like wiring is good now since getting proper 5V reference after cleaning it well.

To go back, it had these crap shifts and funny noises when I got it from the government. I am sure the TPS was bad when I got it. Did I burn up the clutches operating it with a faulty TPS or were the clutches probably already going bad and destined to get steadily worse? The fluid always had a clutch burn/brake pad type smell, but used to be a decent red on the dipstick, not the black it became later.

 

[taskunitbruiser]

Might consider getting AAA+ towing. Will tow 100 miles or 200 miles depending on what level you buy. I do believe that towing to the shop would be covered.

I did get $50 (policy limit) reimbursed from the insurance company for the tow. Helps.

 

[Retiredwarhorses]

Update: I picked up the Humvee at the shop yesterday with the rebuilt transmission. The drive clutches were blown of course. Some parts were upgraded from stock. The guy said it was running good but was shifting late, said would be ok to drive home, but that I needed to get the TPS issue resolved. [He did not want to venture into unfamiliar waters doing that work].

I drive it home, the gym, and the parts store to pick up some electrical contact cleaner and it is shifting well (about 10 miles total). When I get home I sprayed the TPS connector really well with the cleaner to re-test it. I also disconnected the batteries to clear any codes. Now I get the 5V reference! I didnt have alligator clips or my wife home to press the throttle while I tested the variable voltage wire for the TPS. I decided to plug the connector back in (since I had to do that anyway to test the variable voltage) and test drive around the neighborhood. It shifted like complete shit and went into limp mode.

This morning I jumped the J2 and put it into diagnostic mode. It just does cycles of 12, which is normal. Tried to drive again and was out of limp mode but really late hard shifts, noisy/squeaking shifts, etc. Shit basically, and I am very afraid to damage the transmission I just paid to be rebuilt. At this point I am thinking the TPS sensor is trash and maybe the TCM does better with no signal than a complete garbage signal. It isn't perfect and I have some anxiety pushing it up hills hard, but it is shifting much like it did when I picked it up from the shop (where sensor wire was unplugged). That was a relief. Picked one of my kids up from school in this setup and performed ok.

So I am quite sure the TPS is bad. Does anyone still think my TCM is bad? Seems like wiring is good now since getting proper 5V reference after cleaning it well.

To go back, it had these crap shifts and funny noises when I got it from the government. I am sure the TPS was bad when I got it. Did I burn up the clutches operating it with a faulty TPS or were the clutches probably already going bad and destined to get steadily worse? The fluid always had a clutch burn/brake pad type smell, but used to be a decent red on the dipstick, not the black it became later.

Are you waiting on something before you just spend a few extra bucks and replace the TPS?
also, to Set and adjust the TPS, you rotate the throttle linkage At the Injection pump.
I also wouldnt use a transmission shop that doesn’t know how to adjust a TPS on a 90’s GM product, that’s pretty sad, they should have The
scanner to see exactly what the tcm is doing as well as the scanner can act as the TCM to eliminate the TCM as a culprit.

 

[taskunitbruiser]

I just ordered a new TPS.

Are you referencing the Tech 2 scan tool? Where does it plug in? (unlikely to have a J1?)

 

[Retiredwarhorses]

I just ordered a new TPS.

Are you referencing the Tech 2 scan tool? Where does it plug in? (unlikely to have a J1?)

The harness connections are OEM like all GM connectors for the transmission, A tech with proper tools can connect inline and perform diagnostics both ways while in monitor mode or control the transmission altogether.