4l80E, What to be done to tow heavy, as in HEAVY!!

[cabodiver]

Hi guys, I am new to the forum and appreciate the info this great site has given me in the past. I am retired military and live in cabo, mexico so most times I only get one shot at doing something right or I may be down for a while. anyways I just bought a used 1995 k2500 burb, 7.4 with the 4l80e, np 241, 160,000 miles. Truck is in great shape and runs smooth. I am changing the gears to 488 and have already taken off the smog gadgets and put on 33" tires with the two 2" lift keys up front on the torsions. Today I will put in the manual front axle posi lock disconnect kit and rear air bags tomorrow. Gives me the ability to move around in low gear without the front axle engaged. I tow an 18,000 lb boat. yes, 9 tons. I have towed it for years with my past truck an 89 k3500 with a th400 that was gone through by pact. I am not familiar at all with this 4l80e tranny. what should I do? I love the 4th gear but am I better off trying to change in another th400 or 700r4? what about the TC? Should I change the tc to a different stall speed? if so what? The motor is strong and I have already done k&n intake, headers and exhaust with no more cat. I have the heated O2 sensor in and will be putiing in a better cam and heads along with a chip. I need answers quick, I need to hook up next week and don't want to leave pieces and parts on the ramp. Thanks guys for all your info and a speedy response.

 

[19trax95]

I would tow with the selector in "3". That way it will stay out of overdrive.

 

[cabodiver]

I would tow with the selector in "3". That way it will stay out of overdrive.

thanks for the reply. I had read that somewhere else as well. sounds like good advice to me. what I am more concerned about is the initial hook up, like when starting to pull it out of water. that is when max load is against her. boat, trailer, with water resistance and uphill. can thjis tranny handle it in stock form?

 

[sewlow]

A trans cooler, & an RV shift kit or have it reprogramed. Do a service job, -new oil, filter & gasket.
The 4L80e (the 'e' stands for electronic) is a better, stronger tranny than the 700R4, which is basically a non-electronically controlled 4L60e.
The 2 'e' tranny's are sort of different from each other in the way that TH350's & TH400's are.
If you wanna spend some bucks (!) you might (MIGHT!) be able to use a TH400, backed up by a Gear Vendor's over/underdrive, or similar unit. Although wether it should be installed before or after the transfer case, if that is even possible, is a whole 'nuther question. The GV overdrives can be found in Class 'C' motorhomes.
Not really familiar with 4X's, so I may be giving ya false hope! Lol! Fabbing one to work with a 4X4 may be a nightmare.
I do know that the overdrive units are pretty simple in operation, & work fully automatically. A simple on or off switch. They'll handle up to 1000HP, in stock form.
Someone here may have some experience doing this, if it's even possible. Just a thought!

 

[94Sierra4x4]

4 Low, 1st gear, crawl up the ramp until your on flat
If it's a decent boat launch you should be fine coming out of there heh
I realize that's a lot of weight lol

 

[great white]

Thats pretty heavy work for a 4l80e.

Miles are reasonable on your unit, 300,000 is a normal expectation for them if not abused.

The 4l80e is much stronger in stock form than a 700r4.

The 80 is a clutch and disc transmission and the 700 is a "band" type is why.

The 4l80e is a stout unit, it was the "top dog" at GM until the 4l85e came out and then the allison when the duramax came out.

It does have weak points though. Your year will have the drilled input shaft (oil passage), around 99-ish they went to a solid shaft.

It may also be worth your time to get a recalibrated "chip" and have your line pressure tweaked up a bit and your shift points adjusted being that heavy.

I wouldn't even consider 4th and OD pulling 18,000 lbs. You will frag the small lockup disc in the transmission pretty quickly at that weight. There's a few other small gotchas waiting in there like the shell bolt, which you very well might find towing that heavy.

Another thing to consider is a "performance build" transmission boasting a rating of *** hundreds of lb/ft is very different than a tow rated transmission build. You can get 700 r4's with very high ratings, but it' not the same as a sustained load.

Your burb should have an external cooler. If it doesn't then gt one. A BIG one considering where you live. If it has an external cooler already, consider a bigger one. Heat frags a transmission faster then you can say "bingo" and your intended use is going to generate a lot of heat....

I'm sure you know this already and i don't want to play weight police but you are double the tow rating on your burb at that weight. That is way, way waaaaaaayyy overloaded.

A 1 ton 454 4:10 truck is rated at 10,000 lbs towing weight, just for consideration.

The 4:88's will help, but I personally wouldn't be towing that heavy. Even less so on 33's and a lift.

You need E rated tires at least, not LT.

You're going to gross around 25,000 lbs up and rolling.

Do not fool around with anything less than E rated tires.

Personally, I'd be looking for a different tow vehicle at that kind of load.......

Cheers.

 

[19trax95]

^^^ LT is not a tire rating. It stands for "light truck" and is used as a designation. Such as LT245/75-R16. Then the load range which is E. (Or D) but you are correct in that he needs load range E tires.

 

[great white]

^^^ LT is not a tire rating. It stands for "light truck" and is used as a designation. Such as LT245/75-R16. Then the load range which is E. (Or D) but you are correct in that he needs load range E tires.

Jeez, ya make one misstep and ya get jumped all over.

D range isn't gonna cut it either.

My 2500 requires E range and 80 psi to meet it's ratings of 8600 gvwr and 8500 lb trailer with a wd hitch.

Mine is factory rated 8500 vice 10,000 as it has the 6.5 with 4:10 and not the 7.4 with 4:10.

It can haul considerably more than that (it's far from stock in more than just the engine), but I won't any more than maybe around the block. I've moved bobcats, backhoes and heavier construction equipment without issue, but only so far (ie: on site or just down the road).

Long distance tow above rated weight is not something I'm in for. If i need to haul more weight and further, i'll get the right tool for the job.

Anyways, back to topic and 4l80e questions....

 

[thz71]

I wana see pics of this burb sounds sweet with all the work your doin to it

 

[Tavi]

Jeez, ya make one misstep and ya get jumped all over.

Long distance tow above rated weight is not something I'm in for. If i need to haul more weight and further, i'll get the right tool for the job.

I was thinking the same thing about getting jumped on. Your one of the most informative people on the forum. I always enjoy the odometer reference.

And I agree. Over loading is kind of a peeve of mine. See so many people with rangers and s-10s, and way too many half tons. Saying if it moves it. It is good. I bought my truck for its capability. Little did i know it was far lower than I was expecting. 10,000lbs for a towing for a dually? So had to change plans. Smaller trailer in the works.

And i second pics of the burb.