Loud Whine from Transmission Today

[DonYukon]

I just checked the RPO code label in the glove box, and I found the code MT1, which, if my research is correct, indicates that I already have a 4L80E, which means I've somehow managed to have likely destroyed a supposedly indestructible transmission!

So no upgrades needed. It came with one from the factory.

c

That trans is a monster. put it this way about 5 years ago we put one in a friends drag truck with 730 wheel HP. since then the truck has been through 1 upper engine rebuild and one block and 2 turbos and blew a carrier in a 14 bolt Semi float axle. trans is still good and was not rebuilt when it came from its donor truck with 70k ish miles

 

[cc333]

So basically, if I get another one, it should last the life of the truck?

If the 4L80E is such a monster, why is mine dead?

c

 

[alpinecrick]

I checked the fluid again, and it was dark brown, very thin, and smelled burnt.

Could the fix be as simple as changing the fluid, or do I need to start looking for a new truck? I ask because I don't really want to spend $3,000+ for a transmission job unless I have to, because it seems like every time I do something like that to get everything going smoothly, something like this happens and makes it all feel pointless.

I heard these trucks were supposed to be reliable, so what's going on here? Did I get a lemon?

c

These trucks are as reliable as the owners make them.

The 4L80E is the strongest 4 speed auto out there, just like it's predecessor, the TH400, is the strongest 3 speed auto.

Being short on divulging info we have no idea how many miles on your truck/transmission.

In my experience transmission fluid doesn't become dark in a short time, it requires being overheated more than once before that happens.

On flat ground, assuming the location "Limbo" isn't located in the Himalayan Highlands, 210 degrees is not normal operating temp for a 4L60E or 4L80E in my experience, and most likely there is/was something else going on.

Keeping the fluid bright red in ANY automatic transmission contributes greatly to its longevity.

Handing a good rebuilder a 4L80E to rebuild should cost around $1200-$1300 last I checked. If the shop has to pull and install the trans it will certainly add to the cost.

 

[DonYukon]

So basically, if I get another one, it should last the life of the truck?

If the 4L80E is such a monster, why is mine dead?

c

No idea honestly . You can ask nearly everyone here has probably blown up a 4l60 or two . Im on my third rebuild . Not to many have had to rebuild the 4l80. Nothing is really bullet proof if not maintained properly. Im not saying you dont take care of it but maybe the previous owner didn't. Also from what it sounds like its the clutch packs that are burnt up. because from what I read it was having problems shifting unless you used a high enough RPM. which at that point the hydraulic pressure would get high enough to essentially force it into the next gear. what year is the truck?

 

[DonYukon]

Handing a good rebuilder a 4L80E to rebuild should cost around $1200-$1300 last I checked. If the shop has to pull and install the trans it will certainly add to the cost.

I meant to bring this up too. maybe a complete trans ready to drop in would cost 3k but not a rebuild

 

[cc333]

what year is the truck?

It's a 94. Late model I think, as it has a square parking brake pedal, which I read somewhere on this forum indicated a late 94 truck, as opposed to early 94 and below, which have a trapezoidal pedal.

On flat ground, assuming the location "Limbo" isn't located in the Himalayan Highlands, 210 degrees is not normal operating temp for a 4L60E or 4L80E in my experience, and most likely there is/was something else going on.

Well, I'm in the mainland US, out in the mostly desiccated and burnt west, in Northern California for the moment, so there's some hills, but it was mostly on flat ground that the high temps happened. Last year, the truck overheated a couple times (I shut it off to rest ASAP both times). This probably set the transmission up for failure, and yesterday was the last straw.

I try to keep it serviced regularly, but I wouldn't be surprised if the prior owner neglected it a bit, as it seemed like it needed lots of work even when I first bought it in 2017.

Being short on divulging info we have no idea how many miles on your truck/transmission

Sorry, it has 105k miles, much too young to be having these many issues unless someone abused it.

c

 

[alpinecrick]

Sorry, it has 105k miles, much too young to be having these many issues unless someone abused it.

c

That is very low miles for the year. Short of zero maintenance by previous owner(s) I would be a bit suspicious of the odometer reading. My understanding is Cali is pretty strict about that stuff, but still.......

 

[cc333]

That is very low miles for the year.

I know! That's why I'm so upset by all this.

I'm beginning to think that 3 years of shoddy mechanic work by that jerk mechanic (who kept telling me he was doing all these maintenance things, when he apparently wasn't) took its toll, and now I'm stuck.

I feel really stupid for ever trusting that idiot....

Short of zero maintenance by previous owner(s) I would be a bit suspicious of the odometer reading.

I'm starting to wonder that myself. The sorts of problems it's had seem indicative of a truck with 250k+ hard miles, not 105k easy ones! Is there any way of proving whether or not the odometer has been tampered with?

I dunno. I've read about some of the fancy mods you and others have described on these forums, and I'm tempted to make this into a project and have fun with it (I still might, if circumstances allow, because I *really* like this truck!), but I need a solid, reliable truck for towing my horse right now, and I can't be messing around with a half-broken truck when a fire's coming and I need to get out ASAP.

Anyway, since I already have a 4L80E, no conversions are necessary and I should just be able to get another one for $500-$1,000, drop the old one out and lift the new one in easily enough, so I might ask around and see if any friends-of-friends can help me out with it for cheap, because I suspect, as I mentioned earlier, that most of the cost is in the labor.

c

 

[stutaeng]

They are very robust units because they came with vehicles with high GVWR that were workhorses, but anything will and does fail. I think they are good for up to 18,000 lbs GVWR. They were also used in some exotic cars like Bentleys and Rolls Royce. Mostly it seems it's seals and bushings that wear on them.

These units are basically as new as 14 years old or as old as 30!

A tranmission shop should give you a warranty on time or mileage if you go that route.

If you swap it, well, there's risks involved. But I've seen even wrecking yards give short warranties, LOL. Either it works or it doesn't. Plenty of guys running around with junkyard units with unknown mileage. Either case requires flushing the lines/cooler to get old fluid out. Get torque converter flushed as well or a remanufactured one.

I think if you run a Carfax it will tell you when the last mileage was recorded during service.

 

[cc333]

I think if you run a Carfax it will tell you when the last mileage was recorded during service.

That's a fine idea! I don't know why I never thought to do that!

I'll have to pay though. Hmm, I'll look into it.

c