More Useless Information.....

[95TwinTT]

I keep forgetting to bring up gear ratios when the discussions surround 4L60e and 4L80e transmissions.

Many of you are interested in beefing up the horsepower of your engines. Often the way that power is used is over looked.

It's no secret that the 4L60e's have a weakness in the 3/4 clutch disc's. The 4L80e makes any of these trucks bullet proof in the trany department.

That brings us to the gear ratio issue.

The 4L60e has a deeper first gear and wider range between the gears.

The 4L80e is more like a close ration four speed manual.

4L60e ratios..... 1st 3.059:1 / 2nd 1.625:1 / 3rd 1:1 / 4th .696:1

4L80e ratios... 1st 2.482:1 / 2nd 1.482:1 / 3rd 1:1 / 4th .750:1

So your saying to yourself, who cares? Well, to get one of these 5600 pound slugs to move it is a matter of gear ratios and stall speed on the TC, not just horsepower.

Just something to consider when thinking about the 4L80e. It all depends on how you will be using the truck. I'm not selling anything here, just wanted to bring it up so anyone thinking about the swap will consider all the angles.

I am extremely pleased with my 4L80e and think it was one of the better mod's to the old truck. But I am also taking advantage of "all" of the features available with the trans including the paddle shifter.

That's it from here. Just thought I would share and waste some ink......

 

[JKmotorsports]

Good info. One of the reasons I don't like the 4l60 is the wide range between 1st and 2nd. RPMs drop too low when the trans shifts to 2nd. The deeper 1st gear is nice, but with the right tc and rear gears, the higher 1st in the 4l80 is easily remedied.
I bet the paddle shifter is nice:thumbsup:

 

[YukonMud]

Great Post!

 

[HitandRunDriver]

Do you have an idea of how much horsepower and torque you can run the 4l60e with before wear becomes an issue and switching to the 4l80e seems like a good idea.

 

[95TwinTT]

From my experience and from what I read and hear from other guys pushing the limits, five to six hundred HP at the crank, seems to be the practical limit. That is assuming that you are controlling the pressures to the max and all of the internals have been beefed up to the max.
We also have to consider the weight of the vehicle, it is leaning against and how aggressively you drive.

I do so much screwing around with these transmissions, that I have a transmission pressure gauge, built into the dash, or actually it is on the side of the windshield, in a “pod†mount. Each time we would make changes to the transmission, I would make my first stop of each maiden voyage, at the transmission shop, where I would pick up the owner and 4L60e technician. We would then go on a road test, where he would drive and I would have the laptop computer, setting the pressures where he wanted them, in each gear.

With the Camaro, we are typically holding 240 psi, through a WOT 2 / 3 shift. If the slippage on those clutch disc’s can be held to a minimum, they live for quite a while. The TCI, control unit makes programming extremely simple. It is this controller that also has the option for the paddle shifter.

So far, the 4L60e in my Camaro is doing just fine. It of course has the advantage of only weighing 3400 pounds. The Tahoe’s, 4L60e lost 3rd and 4th on the drag strip last year, and that was only at 12 pounds boost from the hair driers. I think the extra 2200 pounds of weight of the Tahoe is the deal breaker when it comes to expecting the trans to hold up to 600 hp. Picking up that extra weight under WOT is too much for the ¾ clutch pack.

I am going to be taking the boost up to 20 psi soon, so I had to go to the 4L80, because the crankshaft power will be somewhere, over 900 hp at that amount of boost. The 80 handles it without getting crazy with pressure. Even so, we went to the special input shaft that is good to 1,000 hp and added a torque multiplying, locking TC with 3200 stall.

We have been using Rossler as a source for “speed partsâ€. They also offer transmissions already built up. I also use their tran’s brakes for both the 4L80e and the 4L60e.

These new performance torque converters have multiple disc’s for the lock up. The locking TC is a must when going to the higher stall speed TC’s. Technology advances in these TC’s has come a long ways. I have discovered that the Torque Converter is not a place to cut costs.

Even if you stay with your stock 4L60e trans, you MUST make changes to the controlling software if you add power to the engine. I don’t know anything about changing the program on the ECM on these trucks. I use a separate controller for mine.

Enough guys have made that mistake that the 4L60e has a bit of a bad reputation. With older “non electronic†tranny’s, you just pull a bit more on the TV cable and problem solved, with these guys, editing must be done in the computer.

Maybe there is someone on the forum here that knows how to make the changes to the ECM?

OK, that’s it from here. I’m going to stop wasting ink now. Good luck

 

[T-Bagg]

I've yet to see you waste ink 95TwinTT.

 

[treepete]

yeah, its these posts that make me well up.

 

[95TwinTT]

You guys want to talk about other ways to waste money. I can help you with that............... :yesnod:

 

[2000 limited]

bump!!! i am a new member here and i did some searching for this and found it. here is my?'s i would like to do this swap cause its a mater of time before my tranny goes. so does the 4l80e bolt right up there to my tahoe? can i use a tc from a 4l80e or get a new stock one that i have on my tahoe? and also does the pcm need to be tuned for this swap? any and every info would be great. i don't wanna drag race with this i just want a bulletproof tranny that will last me a long time. and if i do need to get a tune can black bear performance do what is needed. or can my local dealer do this? i have a 2000 limited edition tahoeopc:

 

[95TwinTT]

GM is pretty good about keeping components compatible.

There should be no problem bolting a 4L80e into your truck. The transmission shop I work with had all the parts for mine. Some new some used. They rebuilt a used 4L80e they had in stock and I dropped off my transfer case to have the larger shaft installed in it.

The rear drive shaft had to be shortened and the larger u-joint and spline welded on. I had a new front drive shaft made up. That one uses the same u-joints, but the shaft had to be about 4†longer.

You also need a new dip stick and tube. My 95 has OBD1, so I did not attempt to use the stock computer. I believe the OBD2 can be hooked up for the 4L80e, but it would require someone with specific knowledge of wiring and applications.

I find it cheaper and easier to use the stand alone computer from TCI. Their TCU (Trans control unit) can do a much better job of controlling the trans. It comes with a wiring harness that plugs right into the trans. These “TCU’s†show up on ebay from time to time and go for about $250 on ebay. The wiring harness can be bought separate from TCI, if a used one does not come with the harness. You just use your laptop with their software to program the shift points and all. It's very easy and user friendly.

The rear mount was the same, I just unbolted the cross member and slid it back to the next set of holes in the frame.

To this day, I still think the 4L80e was the best mod to my truck.

A good transmission shop may be the best resource for guiding you on the swap. :cool2:

 

[newmarketEOD]

Okay now with all your transmission knowledge i have a question on a non speed and HP question.

I have a tahoe, 6 inch lift and 35s that i will be using to tow a full car trailer with a built cherokee on it. My transmission is at about 230 thousand miles, would I be better off with rebuilding the 4L60E and keeping the lower first gear for the torque, or getting my hands on a 4L80E. This is a 98 tahoe with the vortec 350 if that makes any difference.

 

[95TwinTT]

Okay now with all your transmission knowledge i have a question on a non speed and HP question.

I have a tahoe, 6 inch lift and 35s that i will be using to tow a full car trailer with a built cherokee on it. My transmission is at about 230 thousand miles, would I be better off with rebuilding the 4L60E and keeping the lower first gear for the torque, or getting my hands on a 4L80E. This is a 98 tahoe with the vortec 350 if that makes any difference.

For your application, I would just rebuild the 4L60e. You are not making enough power to be a problem for the trans.

You would gain a lot of performance and make life easier for your transmission if you dropped the axle ratios to 4:10 or 4:56.

The change to 35" tires on these trucks, that were designed for 30" tires, does add stress to the trans.

I'm running 4:56 gears in mine and I'm still on 30" tires.

I'm not positive, but I would guess you are running 3:42's.

 

[sasquatch094]

hey what kind of torque converters are good for the 4l80E??? give me like towing, performance, Daily driving types of things. i see on TCI.com or whatever the website is, they have like Saturday night driving?? and streetfighter??? like whats the difference in between those???

 

[95TwinTT]

The TCI site describes their transmission with those names. The Sizzler is a trans they sell that is built for up to 300hp. Then they have the Street Fighter, which they build up to take 450 hp. Then they offer the Super Street Fighter which they claim can stand up to 600 hp.

That 600 hp, is thought to be the common sense limit to the 4L60e trans. It also is based on the notion that when you put the pedal to the metal, the vehicle will move quickly.

There in is the problem with these trucks. They are burdened with an extra ton of steel to move, that cars don’t have. It is during that few extra seconds of struggle to get the iron moving that the clutches give out. The clutch pack in the 4L60e is not big enough in diameter or width to offer sufficient area needed for big horsepower.

That is the main difference between the 4L60e and the 4L80e. This is pure physics here. The 4L80e has sufficient clutch area to handle up to 1,000 hp.

As far as TC’s are concerned. That is mostly a personal thing. There are a wide variety of TC’s to choose from. I use a 10†3200 rpm stall TC with lockup.

The higher stall speed TC’s tend to be smaller diameter than stock. To achieve a locking TC, at smaller diameters, they use multiple clutch disc’s for the lockup.

The TC I have in my Hoe uses three disc’s for the locking feature. They can’t get enough area with a single disc to handle the higher hp.

The other thing you need to be aware of is that technology has made it possible for TC’s to multiply torque. I don’t pretend to understand it, but I know that buying the cheapest TC you can find is not wise. It is the key ingredient to the transmission solution.

I’m not dodging your question here, but the answer to the right TC is going to depend on many factors. How much you are willing to spend? What power range you will be in, between what rpm’s? Which transmission you have? What control system? Whether you want lockup or not.

It’s not all that complicated, but I always suggest having a good relationship with a smart transmission man when getting into modifying vehicles. I get my questions together and drive to the transmission shop and have a meeting with the tech. I also take lots of notes……….

I hope this helps………….. :thumbsup:

 

[sasquatch094]

hmm cool cool.. im not to familiar with the work "lock up" i see you used it a couple times.... ?? some help there guy?? thanks

 

[95TwinTT]

Torque converters tend to slip a little all the time. To achieve zero slippage, they came up with a clutch inside the TC that would “lock up†the converter for better fuel economy.

It feels like the last shift in the transmission. The locking feature is automatic. It disengages when you touch the brake or if you increase the throttle setting to accelerate.

I don’t remember exactly when the locking feature started, but it was for sure when the 4 speed overdrives came out.

With electronic controls, the lockup can be programmed to only engage after a specific speed, like say 35 mph. I have mine programmed to be able to lockup in either 3rd gear or 4th gear over 30 mph. That way I have engine braking in the city.

Anyway, I bring it up, because you can buy TC’s without lockup. If your building a car for the strip, you don’t need it.

 

[sasquatch094]

hmm very nice information there.. now i saw something on here before saying you need all new wiring going to the bigger tranny right? is it possible to get that out of a bigger suburban/silverado or something like that with a 350 and 4l80e in it??

 

[95TwinTT]

It’s possible to find what you need from a donor truck, but it’s tricky.

The ECM you have is OBD-1. The OBD-2 ECM is easier to alter the software.

To me the best thing is to just find a TCU “usedâ€, and control the transmission separate from your ECM.

It is easy to do and saves a lot of time and screwing around.

That would also give you the ability to have a “paddle shifter†if you wanted.

I also use several other features of the trans, that can’t be done with the stock ECM.

You should be able to find a TCU and wiring harness for under $400.

 

[sasquatch094]

i know this is really hard to talk about online, but how do you get around your ecm in the obd1 system? like how do you then control it without the ecm catching that its gone???? u get where im coming from? im just lost..

 

[95TwinTT]

It is very simple, you just unplug the OEM connector and plug in the new one from the TCU.

The TCU needs to share the signal with the TPS, speed sensor and tach pulse.

I taped up the old connector end and tucked it up out of the way, to keep it clean, in case I want to go back to it.

The stock ECM does not know the difference. It has no feed back circuits to tell it that you unhooked the connector. For all it knows, it is still shifting the old trans.

TCI sells pig tails to split the TPS signal. Tach pulse and speed sensor can be picked off in several places.

You can do the TCU first with your 4L60e to get used to it, then when you switch to the 4L80e, just click on the menu selection for 4L80e and switch the one jumper in the wiring harness and your setup for the 80.

Both transmissions use the same plug at the trans.