Normal operating temp for 4L80E in a plow truck?

[upper_tanker]

I have a 2000 k2500 regular cab with a 454/4L80E in it. This is my first year plowing with it. I noticed that during the first snow, once I got rolling with it, the trans would kind of hesitate once you put it in reverse and gradually pressed the gas pedal. It would do this until about 5-10 mph in reverse, and then it would "go" like normal.

The next time out, I decided to grab my BT OBD2 dongle out of my Tahoe and plug it in while I was plowing to see what the temps were. It was a 30-40 degree night, so not cold by any means. Once I got going at a steady pace in a parking lot, I was seeing temps of 210-220 degrees F. Once I'd leave the lots and start moving, it would go to 180 or so, even on the expressway.

I feel like this is an absolute issue, but I am looking for advice from you here. My rebuilt 60E In my Tahoe doesn't get above 150, but I don't plow with it. My dad has plowed with this 2000 for the past 10 years, but he says he doesn't remember it doing the reverse issue thing that I said earlier in this post.

The truck has 160k miles and is still in pretty decent shape. There is absolutely NO issues in any of the forward gears, or shifting out of/into gears. The truck has a trans cooler with a fan on it. I have no clue if it's stock or aftermarket, but it looks stock the fan IS working.

TL;DR - is 220 degrees F too hot for a 4L80E in a plow truck? Also, could this be causing my reverse issue? I'd at least like to get this season out of it plowing before I pay to have it rebuilt.

 

[thinger2]

The temp is not causing your reverse problem.
The reverse problem is causing the temp.
The 4l80e is a pretty damn stout and reliable transmission.
The temp doesnt really bother me anyway near as much as the actual behaviour and functionallity of the trans does.
I think you are at a point where you need to decide if you are going to save that trans or run it and burn it and pay the price down the road.
That said, if it was my truck?
I would get the trans rebuilt by a good shop while it is still rebuildable.
I know, you are in a kinda tight spot.
But, if you keep beating it for a another year,
Then you have nothing but a dead truck.

 

[CKVortec]

If you're plowing for profit it wouldn't kill you to have a spare tranny, get one from a junk yard, have it rebuilt and swap it out before you destroy what you have. then you can stick that one in a corner somewhere to be rebuilt if you have signs of immanent failure or if your trans totally fails you have something to get you back up an running (even if limping) on short notice.

 

[Frank Enstein]

In a perfect world 180 all the time. In the real world 160 to 200 is fine. Every 20 degrees above 200 cuts the trans life in half. This is per TCI and I trust them. I have been selling their stuff over 25 years.

+1 on the reverse problem causing the issue. Fix it now or fix it for a bunch more later. Don't shop price for a rebuild shop reputation and customer service.

THEN put an auxiliary trans cooler on the return line to the trans. That way on very cold days the coolant will get the trans up to temp (important for cooking out the moisture from the last time you ran it) and if it gets really hot the coolant will bring down the temp of the trans fluid. Keep adding coolers until it stays at 180 degrees. It is very difficult to over cool a trans plumbed this way.

On a side note engine temp of 215 is ideal for efficiency and longevity. My GMT 800 ran 210 all year round and had 453000 miles on the original engine (and exhaust!) when I sold it.

 

[RichLo]

Agree with everything above. If your plowing for profit, start acting now, shop around for a rebuilt unit and add more coolers. If your plowing for yourself just get through the rest of the year babying it (dont go 10mph in reverse!).

You have options, you can rebuild what you have in the summer. Or swap in a SM465 manual. IMO the stick shift with granny low is the best for plowing.

 

[upper_tanker]

I have no issues paying to get this rebuilt. I finally found a guy to plow for that pays really good, but we need snow here for that. My goal with this truck was to make enough money this first year of plowing for him to get the truck up to *****, and then the next few years would only be minimal maintenance/repair costs and more profit.

I know these 80Es are beasts. My dad has had dozens of these and we've had minimal issues with them. I guess I just wasn't sure where to even start with this issue on this, but he's owned it since 80k miles so I'm sure it's due for a rebuild anyways. I will try to make it one more snow to hopefully get a nice chunk of money to put towards it, and then I'll take it to the trans shop after that. We have a very reputable trans shop here that is pretty costly, but does offer a 1 yr/12k mile warranty on plow truck rebuilds. I'll ask him how much extra to add a cooler to it while it's there since I don't have the time to do it.

 

[stutaeng]

I have an issue with K3500 4L80e that may or not be related to same issue you are having. Mine only does it cold and causes my engine to stall. I created a thread here recently that you may want to read; @andy396 posted very useful link of his build that may be helpful as well: 4L80e delayed shift into D, stalls engine

I don't have information on my transmission fluid temps for that engine, but on my other GMT800 trucks that do have the factory transmission temp guage, I've never really seen anything over 180, but never have worked them really hard either. More on the 160F range even in the Summer.

I believe the "lost reverse" tends to be a somewhat "common" problem on the 4L80e. I don't know if these symptoms are precursor to that problem? My K3500 is hardly used now, so I'm just going to run it like that for the time being. I did seem to have a slight fluid overfill last time I checked, and I don't have any history of the truck since I bought it at 204k 3 years ago. Just know it was formerly a farm truck, so likely not excellent maintenance. My plan is to drop the pan at some point and put new fluid in it.

I hope this helps.

 

[upper_tanker]

I have an issue with K3500 4L80e that may or not be related to same issue you are having. Mine only does it cold and causes my engine to stall. I created a thread here recently that you may want to read; @andy396 posted very useful link of his build that may be helpful as well: 4L80e delayed shift into D, stalls engine

I don't have information on my transmission fluid temps for that engine, but on my other GMT800 trucks that do have the factory transmission temp guage, I've never really seen anything over 180, but never have worked them really hard either. More on the 160F range even in the Summer.

I believe the "lost reverse" tends to be a somewhat "common" problem on the 4L80e. I don't know if these symptoms are precursor to that problem? My K3500 is hardly used now, so I'm just going to run it like that for the time being. I did seem to have a slight fluid overfill last time I checked, and I don't have any history of the truck since I bought it at 204k 3 years ago. Just know it was formerly a farm truck, so likely not excellent maintenance. My plan is to drop the pan at some point and put new fluid in it.

I hope this helps.

Thank you for posting that, I will check that out. My issue is a bit different I think. It has no problem shifting into drive from reverse or vice-versa. It has no issues getting moving in reverse if you give it throttle a little aggressively. I do try to baby the truck, so I don't really beat the crap out of it. It's just a little slow moving in reverse under very light acceleration until you hit a certain point, and then it goes. I was thinking about doing a trans filter/fluid change but have heard nothing but horror stories on a high mileage trans when you do that. I'd rather just have it rebuilt and be done with it.

 

[stutaeng]

I understand. On the new fluid change, the thought is that the particles in the fluid helps with with friction on the clutch packs, I think. Some people swear this is true, but I don't honestly.

On my 99 1500 4L60e last time I went to get it serviced the Penzzoil shop made me sign a waiver because of the "high mileage." At that point it had 220k-ish. Since about 200k I had some valve body code that made a harsh shift under some conditions. I just pulled it because of that valve body issue, and the fluid looked pretty darn clean at 255k still. Could have changed the valve body and kept going on it.

The way I understand it, if you already have metallic particles on your fluid, you are already screwed. So changing the oil doesn't cause the tranny to go...you get the point. But changing your fluid could also get rid of some gunk if your clutches are still good. That theory was probably started by folks that never changed the fluid per manufacturer's recommendations to begin with and tranny is already on the way out, and when it fails after some shop changed the fluid they blame them for it. In reality, it was just a coincidence, LOL.

Anyways, it can be argued both ways.

 

[Schurkey]

once I got rolling with it, the trans would kind of hesitate once you put it in reverse and gradually pressed the gas pedal. It would do this until about 5-10 mph in reverse, and then it would "go" like normal.

Are you saying the trans slips in reverse up to 5--10 mph, then fully-engages? Slipping is NOT GOOD.

is 220 degrees F too hot for a 4L80E in a plow truck? Also, could this be causing my reverse issue?

1. 220 degrees, by itself, is nothing. GM doesn't turn on the second electric engine cooling fan until about that temperature, so GM clearly doesn't care if the trans cooler in the radiator is warming the fluid.

Yes, I remember the old deal about trans life being cut in half for every twenty degree rise in temp. When I first heard that, dinosaurs still roamed the Earth, and the lower temp started at 170 degrees. Now, I guess, the story is starting at 200. It's like every other "rule of thumb"...wildly inaccurate, and perhaps deliberately so. Your trans is not constantly at 220, it's seeing occasional 220.

2. Delayed reverse is a genuine problem. My Trailblazer (4L60E) spent ten-something years with a delayed reverse problem, only when cold. Spring--Summer--Fall--NO PROBLEM. Winter...the colder it got, longer the delay. No reverse at all. Once the trans engaged reverse, it was fine until it sat long enough to fully cool-off again. I though there was something actually wrong with the trans, although I didn't know what it might be. Local trans shop thought "maybe" it had a warped valve body that caused the valve(s) to stick when it contracted from cold.

Last fall, I notice that the fluid is no longer bright red. Turning maroon. I changed the filter and flushed the fluid (15 quarts all together). END of delayed reverse. I still don't understand it. But there it is: Fresh fluid and new filter, it's winter, and it hits reverse like it should...for the first winter in a decade.

The FIRST thing you need to do is to verify the fluid level. If the fluid level isn't right, and the fluid looks reasonably red--adjust fluid level as needed. If the fluid level is appropriate, or the fluid looks burnt...REPLACE THE FILTER AND FLUSH THE FLUID.

The story about particles in the fluid helping the clutches to engage is bullshit. If there's particles in the fluid...your filter isn't working, and the bushings in the transmission are being ground down. REPLACE THE FILTER AND FLUSH THE FLUID.

AFTER you've done that, and IF it's still got delayed reverse, you may need to consider a trans overhaul. This could be a control problem--the valve body or fluid passages not directing fluid to the friction elements the way they should. This could also be a problem with the friction items themselves--"Reverse" is engaged by applying the Low-Reverse band, and the Direct clutch (Ford calls it the "High-Reverse" clutch.)