4L60E

[YukonMud]

I saw several other threads pertaining to transmissions, but I wanted to ask several other questions...I am also not sure if this is the correct thread as I own a 1993 Yukon.

Now to the issues and a little back ground information....I don't drive my truck to often as I also own a car (for gas mileage purposes...In the last 12 months I have driven about 3500 miles) but I do love to take it camping. I also use it to pull my boat. About 3 weeks ago I noticed that my transmission started to slip while driving on the freeway and last weekend I hooked up a 12' U-Haul trailer to help a friend move, not much after I got back on the main road I realized that I could not go over 35 mph. After going straight home, did not help anyone move, I took it to a shop. They mentioned that my 3-4 clutches burned out.

My Yukon is my dream vehicle. At some point I want to replace/upgrade the drive train (engine, transmission, axles), lift it with a 4-6" lift and place some bigger tires under it. Since my transmission has died it looks like I am going to have to move my time table up. After doing some research I realized that I will not be able to put a different transmission in as it would require a new/upgraded computer and a new wiring harness.

With that said I want to make my current transmission "bullet proof".


Will I have any engine limitations with keeping my current transmission?

My future engine will have between 300-600 hp (not sure what I want to do yet).​

What upgrades should I do to my transmission?

Some recommendations thus far: high capacity 3-4 clutch, 'the beast' sun gear shell, 'tow-to-go' kit.​

Whatever I do I want to insure that I can continue my upgrades and insure that the transmission will have a long life ahead of it.

Sorry this post is so long and Thanks for all of you help!!

 

[95TwinTT]

I have had the pleasure of taking the 4L60e trans to the limit of what it could take and beyond.

I am still getting away with it in my 94 Camaro, but that is because it only weighs 3400 pounds. I have every option made for the 4L60e to make it tuff, but they suffer from the fact that they don't have large enough 3/4 clutches. To make up the difference we add to the number of disc's. That helps some, but taking the pressure up makes up the rest.

With the Camaro the 580 rear wheel horsepower, turns into acceleration quickly. With the Tahoe, it's 575 rwhp, has to lean against an extra ton of steel to make it move. That is where the problem comes in.

First and Second are never a problem, it is just Third and Fourth, can't take the torque for very long. Once they start to slip, it is over quickly.

I was frying clutches in the Tahoe often enough, that something had to be done. My transmission guy suggested we take it up to the 4L80e. The 80 has large clutches and can run at normal line pressures while handling the big horsepower.

The conversion was simple. The holes were in the frame to slide the cross member to the next position. Same rear transmission mount. We upgraded the existing transfer case, which just took swapping out the shafts. The only custom work was having a new set of drive shaft's made and lengthening the shift control rod for 2/4 wheel drive.

I am extreme pleased with the performance of the 4L80e. I wish I would have switched sooner.

The gear ratios are different between the two transmissions, but I like the 80 better because it is just like a close ratio 4 speed manual. I also have 4:56 gears and a 3200 stall speed TQ.

4L60 ratios are 3.059 / 1.625 / 1 / .696 to one.

4L80 ratios are 2.482 / 1.482 / 1 / .750 to one.

I also have the "paddle shifter" hooked up, although I don't have it on the steering wheel, but on a switch next on the console, next to the seat.

If you are planning on going up near 600 HP at some point, you might just as well invest in a 4L80e now and make mod's to it as you go. You don't have to do all the mods at first. A stock 4L80 is tuff as nails to start with.

Good luck.

 

[YukonMud]

First off, thank you for all the advice 95TwinTT!

My only concern is the initial investment, today I only have around 3k to put into my Yukon. If I were to switch to the 4l80e what other things would I have to do at the same time, to get it drivable; I am not planning on upgrading the engine/axles for another couple years.

From what I have heard I would have to replace the wiring harness and computer, you mentioned you also replaced/modified the transfer case, drive shafts & shift control rod for 2/4 wheel drive.

Do all of those things need to be done at the same time? Are there any other things you would suggest to add/replace?

Thanks

 

[95TwinTT]

I would just do the 3/4 clutches for now and get it back on the road. Investing any more than what it takes to get it back on the road is throwing good money after bad, as they say.

The trans swap, needs to be done all at the same time. Drive shafts and transfer case, plus the computer. The least expensive way into a 4L80 would be to fine one for sale that needs rebuilding. Also the TCU computer's show up on E-bay every so often. They go for around 200 on Ebay. New ones are a little over $700.00.

The bell housing of the older 4L80e's did not use the top hole for bolting to the engine. You might want to get a trans that is new enough to have that feature.

Other than that, a good torque converter is worth the extra expense. I would go with at least a 3,000 stall speed with lock up capability. They are hard to tell from stock, but can actually multiply the torque if you get the right package. I'm thinking you could get the 4L80e in built up and installed for $2,500 if you shop around a bit.

I'm assuming that you can do some of the work yourself, like wiring and removing and installing the trans. It also helps to have a good relationship with a transmission shop.

If you go through the 4L60e and beef it up with all the goodies, it will cost between $1,500 and 2,000.

If you are serious about working your way to 600 HP, the little extra you spend on the 4L80e, will come back in big dividends by not having to redo you 4L60e every six months.

Rossler is the best resource for the heavy duty parts in the trans. I think they are good about talking to you about alternatives too.

I don't know if this helps, but let me know if I missed something. :shhh: