4L60E life extension

There are many that have done the tranny cooler. Keeping your trans cool is the only way to really extend the lifespan of the 4L60 in these trucks.

I know someone had mentioned previously about using a in-line filter, but it really would defeat the purpose, since you would still have to keep the in trans filter, just because of the design of the OE filter.
 
TollKeeper said:
There are many that have done the tranny cooler. Keeping your trans cool is the only way to really extend the lifespan of the 4L60 in these trucks.

I know someone had mentioned previously about using a in-line filter, but it really would defeat the purpose, since you would still have to keep the in trans filter, just because of the design of the OE filter.
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My thoughts were aiding additional filtration with an easier filter change and to do it more frequently like every other oil change replace the spin on
 
I added a transmission cooler at 130K miles. I added it for towing a small trailer or boat. I have done minimal towing since installation and now have 190K miles on the original transmission. I also do transmission service 30K miles. Filter and Dexron VI. Fingers crossed....so far so good.
 
c good said:
I added a transmission cooler at 130K miles. I added it for towing a small trailer or boat. I have done minimal towing since installation and now have 190K miles on the original transmission. I also do transmission service 30K miles. Filter and Dexron VI. Fingers crossed....so far so good.
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My envoy was purchased with 186 on the clock idk if the trans was ever serviced I'm scared to do one
 
Before I bought mine from a friend, he let me take it to my local shop and have them inspect it. It would be worth having a shop check yours.
 
@Sparkie's Mower Service Here's a post I made last month from a road trip with a new (meaning replacement) aux tranny cooler I put in, and the temp differences I saw. The FL heat here is a good comparison for you.

Blckshdw said:
Saturday mid afternoon, made a drive over to Orlando to meet up with some friends for dinner. Hadn't taken a drive that far in a few years, and the last time I did, the tranny ate itself, and I believe plugged up the thermal bypass in the aux cooler I had at the time.

Since the new aux cooler doesn't have the bypass, I was interested to see what the temps did. For the most part it was an easy drive, set the cruise at 70 after finding an open section of highway and left it there. Coolant stayed around 195, tranny was at 175, both give or take a couple degrees. Got near Disney and ran into a parking lot (as expected). Within about a minute, the tranny temp climbed to 188. I knew the residual heat would do that with the airflow only coming from the fan, but after maybe 5 minutes of 1st gear stop and go, the tranny came back down to 179.

To that point I had all 4 windows down, and decided to put them up and use the AC. Coolant went up to 200 and stayed there, but the tranny readings stayed the same at 179. Once traffic got free flowing again, coolant temp came back down to 195, and tranny back down to 175. Made the drive back home at 11:30 PM, and the tranny temps stayed around 168 due to the cooler night time temps. Very happy with the performance of the Hayden model I got. The thermal bypass on the Tru-Cool that I had before was more trouble than it was worth, given the FL temps.
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Haven't done it myself, but a poster on here (several years ago) put a screw on type oil filter in the trans lines. Apparently the filter has to be changed often, as he said his trans let go due to him not changing the filter often enough.
 
I added the pcmofnc cooler kit (which I now realize is a bit controversial), but I have an Aeroforce gauge that I have always set to trans temp and it made a huge difference in temps. I rarely go over 150 degrees even on hot days under load. Definitely worthwhile and I think the only thing that really makes a big difference in lifespan. Of course, if the trans already has 200k miles it may not make a big enough difference :)
 
An aux cooler is always the first thing I add to any vehicle I come into possession as it is the single most important thing to do to extend the life of any automatic transmission, whether I tow or not.

Only exception is my new Sierra because of the warranty. However, I am rethinking this. It has a beefy cooler separate of the radiator however there is a "thermostat" on the cooler line outlets on the tranny that only opens at around 195f, which is the temp that it seems to hang around. In traffic, I have seen it climb to 215f. While towing, even in +30c, it keeps around 195-200f. They have been doing this since 2014 on the 6L80E. Why? Is it to keep fluid temps high to keep it at a lower viscosity (thinner) to improve MPG? Is it a built-in self destruct?
 
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Mooseman said:
They have been doing this since 2014 on the 6L80E. Why? Is it to keep fluid temps high to keep it at a lower viscosity (thinner) to improve MPG? Is it a built-in self destruct?
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Consistency.... the one thing we can count on when operating a reciprocating assembly is heat. If we let it cool constantly there's no telling what the variation from high to low would be. Put a thermostat and we can count on it being above the thermostat's opening temp and engineer to attempt to keep it as low as possible (but still above the set point). This narrows the operating temperature band. If they can count on a consistent temp (and by extension all the properties affected by it), they can engineer to it (clearances, friction coefficients, etc...).
 
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Valvoline max life ATF is really good synthetic dexron 6 fluid. It has solved driveability issues for me on two vehicles after I did a full fluid exchange.
The internal filter is entirely sufficient and problems with it are extremely rare. An external filter might give you some more time if your transmission is disintegrating but not beneficial under normal circumstances.
 
I did add a small cooler, but I also replaced my seperator plate at about 160K as the check balls were hammering the plate pretty good. One was so bad I was getting a slight flare in the 2-3 shift.

So I went in and replaced the plate, the accumulator pistons, added the vette servo, and so far so good. I'm at 334K miles on the original trans....hope she keeps going.
 
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Lubegard is one of the only transmission additives I'd recommend. It's basically just all of the typical "ingredients" in additive package for a good ATF. No seal swellers or anything like that.
As for the 6l80e coolers, there is a very easy to install thermostat bypass you can purchase. They're maybe $30 and install with just a snap ring pliers.
The reason the thermostat is installed is for a couple reasons.
A. The TCM has a temperature limit that is hard set (or at least I've never been able to adjust it with HPtuners or EFI-Live) that won't allow lockup until you're up to temp. Some drivers complained of driving feeling weird in cold climates because the vehicle feels different not locked up. This thermostat helped the transmission get up to temp more quickly
B. efficiency. Warmer operating temps is better for mileage
 
For that .2 MPG, I'd go for tranny longevity.
 
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I'm surprised they haven't found a way to warm up the diff for another .2 MPG :laugh:
 
It has a beefy cooler separate of the radiator however there is a "thermostat" on the cooler line outlets on the tranny that only opens at around 195f, which is the temp that it seems to hang around. In traffic, I have seen it climb to 215f. While towing, even in +30c, it keeps around 195-200f. They have been doing this since 2014 on the 6L80E. Why? Is it to keep fluid temps high to keep it at a lower viscosity (thinner) to improve MPG?
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That's really interesting, I never thought to extrapolate to trans fluid temps...

Any cooling system with a thermostat is designed to raise the temp to the thermostat opening temp. the thermostat has nothing to do with cooling it's for warming.

I took the thermostat out of the Envoy last summer and I had trouble getting the coolant above 65C/150F. I put it back in and it sits just shy of 100C all the time, the addition of the thermostat warms the system up, it doesn't cool it off.

The same would be true for a thermostat in a transmission cooler line, without it the trans fluid may get too cold.

Now I wonder if the addition of the PCMofNC cooler I installed is making my trans fluid too cold, maybe I need to retrofit a thermostat from a 6L80E into my system.
 
I don't think you could. It attaches to the tranny with special ports. In fact, some of the bypasses are entire blocks that replace the thermostat. And even if you could, you shouldn't. When I was towing with the Avalanche with its 6.0L and 4L70E, it got hot, even with the extra cooler. However, I have seen in-line thermostats for tranny coolers that could be added to the aux cooler if you think it's running too cool, like in -20c. I always ran mine without such controls, even in really cold temps, I never had any problems.

So far I haven't seen temps high enough in my Sierra's 10L90E to warrant removing it yet. I have heard of failures of these thermostats that have fried trannys in the past. The 6L80E didn't have one until 2014 so why add one? I think it's all BS.
 
JayArr said:
That's really interesting, I never thought to extrapolate to trans fluid temps...

Any cooling system with a thermostat is designed to raise the temp to the thermostat opening temp. the thermostat has nothing to do with cooling it's for warming.

I took the thermostat out of the Envoy last summer and I had trouble getting the coolant above 65C/150F. I put it back in and it sits just shy of 100C all the time, the addition of the thermostat warms the system up, it doesn't cool it off.

The same would be true for a thermostat in a transmission cooler line, without it the trans fluid may get too cold.

Now I wonder if the addition of the PCMofNC cooler I installed is making my trans fluid too cold, maybe I need to retrofit a thermostat from a 6L80E into my system.
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This is absolutely true!!! As long as the thermostat itself isn't a restriction to the circuit, or if we assume the thermostat doesn't have issues.

The issue with the thermostat in the 6l80e family of transmissions...is both.
It is a flow restriction
And they often have issues. Sometimes stuck totally closed (nuclear meltdown for someone who doesn't notice/catch it) or sometimes their travel gets limited and acts as a partial bypass loop for cooler oil.
 
However, I have seen in-line thermostats for tranny coolers that could be added to the aux cooler if you think it's running too cool,
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Yes, this!

I'm wondering if the extra radiator for the trans is now overcooling the fluid when I'm not towing anything and/or in the winter.

Can I get a transmission fluid temp on Torque Flight or do I need my Tech II?
 
Torque has several PIDs for trans fluid temp (221940, 221949).
See Settings > Manage extra PIDs/Sensors > Add predefined set > GM/Opel)
 
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I finally got back to this issue today and programmed trans fluid temp into my Torque Pro and took the vehicle for a drive.

It was about 5C outside (41F)

I drove about 1.5 miles to the store, bought milk and then drove home.

The fluid started at 5C and only rose to 33C (91F).

The coolant was up to temp by the time I got to the store but the trans fluid lagged far behind.

It started to slowly climb on the way home but keep in mind that when I installed the aux trans fluid cooler I left the plumbing to the internal radiator OEM cooler intact.

I think what's happening right now is that the radiator coolant is warming the trans fluid.

Is the trans cooler in the radiator supposed to cool the trans fluid or warm it?

JayArr
 
JayArr said:
The coolant was up to temp by the time I got to the store but the trans fluid lagged far behind.
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This is normal. I have a Sierra w/ factory external cooler and dash gauge. It takes much longer to get the fluid up to temp, vs. engine oil and coolant. Especially if you're under steady state cruise, vs. continuously shifting up / down (stoplights, etc.) It can take an hour for mine to get to 150F on the gauge, which is where it normally sits at when warm (I think 'full operating temp' is 160F, IIRC)

JayArr said:
Is the trans cooler in the radiator supposed to cool the trans fluid or warm it?
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Cool only. It doesn't need help to get warm... LOL. Friction creates heat.

If you have the external cooler plumbed in series with the factory cooler, it'll be that much longer to get to op temp. BTW, if you do have them in series, the aux cooler should be last, before the fluid is sent back to the trans, as it will cool more / better than the factory cooler will.

My V8 Envoy bypasses the factory cooler and runs on a small 10K BTU Derale stacked plate. Unless I'm towing 5000 lb with it up mountains in hot summer temps (which I don't do anymore), it runs about 165-180F, depending on the season, and *never* goes past that point.
 
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The radiator 100% will help get the fluid up to temp more quickly in a cold climate.
typically with a factory cooler setup that only runs through the radiator, the transmission will operate within about 15 degrees F of whatever the engine is operating at.
And in cold climates, it's important for that oil to get up to temp as quickly as the engine because fluid that is too cold does not perform as good as warm fluid, and the time saved getting up to temp is better for economy.
 
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My main concern is that in order to stay cool while pulling our travel trailer through the mountains in the summer I've now set the vehicle up to run with cold trans fluid all winter. A quick google search has me believing that trans fluid should be about 170F for the shifts and clutches to operate properly and that some vehicle computers won't lock into overdrive if the fluid is below a set threshold.

I'd love a set of reference data, would someone without an external cooler put PID 221940 into their Torque Pro and watch it next time they have to go out for a drive?

My instinct is to put a Derale thermostat after the stock radiator but before the PCM of NC external cooler. This way on cold days the external cooler is left out of the system completely until/unless the trans fluid reaches 180F. Driving without a trailer in the winter that may never happen.
 
JayArr said:
I'd love a set of reference data, would someone without an external cooler put PID 221940 into their Torque Pro and watch it next time they have to go out for a drive?
Click to expand...


I save my past data recordings from Car Scanner. Here is a sample from last year about this time ....

A quick edit: I have seen that my engine oil temp sensor is not accurate at low temps. This can be seen as it is always a good deal colder than both the trans fluid and engine coolant temps at dead cold startups.

Screenshot_20221107-193439.jpg
 
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