Time to Get Serious With 4L60e/4L65e Cooling...

[alpinecrick]

The TruCool 40K GVW cooler is NOT a LPD cooler. For those who live above or below the equator LPD coolers are a good thing for the trans when it's cold outside (and I don't mean only when it's 20 below).

Edit to add:
I have one of these I picked up really cheap in the event I do use something like the 40K cooler. It does the same thing as a LPD:
https://derale.com/product-footer/fluid-coolers/thermostats-1/fluid-control-thermostats/13011-detail

2nd Edit:
I bet half the condensers on trucks with 50k or more on them are partially filled with debris/dirt in the fins.........
Pull the top and bottom shrouds, fan and clutch, radiator brackets, shine a flashlight from the backside of the condenser and see how plugged the condenser is.

 

[df2x4]

As much as I'd love to go that route, I really can't. Swapping the transmission means tuning the factory computers, making the truck unsmoggable. California is a weird place...

Just playing devil's advocate here as an outside observer... But how do they verify something like this? Is it a VIN check or something? I bet there's a way to get it done under the radar. Maybe someone more well versed in tuning can chime in on that. Diesel K1500 'burbs were available with the 4L80E so it was technically part of a factory combo in your exact chassis.

I wish you the best of luck and I hope this solves your issues, but I do think your lift/tire combo combined with towing is probably stressing the 4L60Es pretty hard. I'd say the fact that you've blown up a few of them is evidence of that. Just out of curiosity what gears are you running in the differentials?

 

[Curt]

A few things....

The temps on Curt's trans seem to be awful high for towing a boat that size, even in the rolling hills of the Bay Area. I'm wondering if there is more going on with the trans and cooling. The 5 3/4x11 standard size stacked plate cooler is a good cooler. Stacked plate coolers are 10-20% more efficient than tube and fin coolers, and are a lot more robust concerning vibration or impact from rocks and such--important because it's the tip of the spear once stuff gets past the grill.

I'm considering the 8x11 or 11x11 stacked plate cooler with a small 10"-12" e-fan to cool my 4l60e's on the 96 and 97 for when I do pull my 18ft TT or my other trailers ('cause I'm thinking about selling my Sierra TD).

The tubes in the DeRale WILL plug up if you off road or drive muddy roads, I know a guy who has one. Plus the DeRale does hang down further than the CRF pan. The CRF doesn't evoke any concern about clearance issues the way the DeRale does, at least in my mind. The CRF does hold 6 1/2 qts--I've measured several times when I drain them (which is two or three times a year because I keep the fluid bright red). Clean ATF carries heat away better, and that goes for any other fluid in the vehicle.

I agree. Something is up, I expected high temps while towing, but it blew my mind to see the gauge pegged to the point where the trans started slipping. I was also worried about that pan with holes and clogging. Thanks for confirming my suspicion on that. Definitely sold on that pan you linked. Pops agrees too, not a fan of the pan hanging down low.

 

[Curt]

The TruCool 40K GVW cooler is NOT a LPD cooler. For those who live above or below the equator LPD coolers are a good thing for the trans when it's cold outside (and I don't mean only when it's 20 below).

Edit to add:
I have one of these I picked up really cheap in the event I do use something like the 40K cooler. It does the same thing as a LPD:
https://derale.com/product-footer/fluid-coolers/thermostats-1/fluid-control-thermostats/13011-detail

2nd Edit:
I bet half the condensers on trucks with 50k or more on them are partially filled with debris/dirt in the fins.........
Pull the top and bottom shrouds, fan and clutch, radiator brackets, shine a flashlight from the backside of the condenser and see how plugged the condenser is.

Shoot... it's not? I'm looking at the Amazon link and they state its an LPD cooler. https://www.amazon.com/Tru-Cool-LPD...APQF94JE27J&psc=1&refRID=2Q1JDQSMBAPQF94JE27J.

Just playing devil's advocate here as an outside observer... But how do they verify something like this? Is it a VIN check or something? I bet there's a way to get it done under the radar. Maybe someone more well versed in tuning can chime in on that. Diesel K1500 'burbs were available with the 4L80E so it was technically part of a factory combo in your exact chassis.

I wish you the best of luck and I hope this solves your issues, but I do think your lift/tire combo combined with towing is probably stressing the 4L60Es pretty hard. I'd say the fact that you've blown up a few of them is evidence of that. Just out of curiosity what gears are you running in the differentials?

Yeah, they verify everything by plugging the SMOG computer into the OBDII and that computer checks everything, along with a visual inspection. Honestly, it's all up to the SMOG checker person with the visual. I had a guy who helped us SMOG one of our other vehicles with LT headers, but it's a pain in the neck and always a gamble. Also, paying someone $500 for a hot SMOG every 2 years isn't really an option I'd entertain either. I could see the 4L80e option being a great way to go if I didn't live in this state with garbage laws.

The thing about SMOG is it has to come factory equipped in your vehicle, or be a CARB legal modification. Even if the diesel K1500 suburban came with a 4l80e, my suburban didn't come with those components from the factory. Basically allows for zero legal flexibility in customization. Sure you can get away with anything as long as you don't touch the computers or trip the CEL. There are always workarounds, which I know of and have access too, but I've learned it's not worth the hassle anymore. If I have to start worrying about SMOG on this truck, it won't be worth it to me anymore.

I agree. The lift, tires, and gearing set-up isn't the best in my truck, and most likely the reason it is a 4L60e murderer. I'm hoping by beefing up the cooling capability 1000x this will be the last transmission this truck will ever see.

I will get some feedback from running 3.42 gearing in the truck (I know, not optimal) but I like to cruise doing 80 MPH (GPS confirmed) on the freeway without drinking gas (not towing, obviously). With my 3.42 gearing I can cruise at 80 MPH around 1900 RPM in OD.

 

[df2x4]

I will get some feedback from running 3.42 gearing in the truck (I know, not optimal) but I like to cruise doing 80 MPH (GPS confirmed) on the freeway without drinking gas (not towing, obviously). With my 3.42 gearing I can cruise at 80 MPH around 1900 RPM in OD.

Yeah, that's definitely not doing your transmissions any favors. If I were forced to stick with a 60E in your situation I'd think about changing up to at least 4.10s. That's also going to involve a tune though.

 

[Curt]

Yeah, that's definitely not doing your transmissions any favors. If I were forced to stick with a 60E in your situation I'd think about changing up to at least 4.10s. That's also going to involve a tune though.

Haha yeah, I'm fully aware. One of the things really holding me back from changing anything drivetrain related is the money we spent replacing all of it a couple summers ago. Got the new GM crate 5.7, 65e, along with the Detriot TrueTrac gears in the rear-end. I wanted to re-gear the rear while we were doing all of it but then I'd have to re-gear the front diff as well. Didn't have the money for that so ended up sticking with the beefier 3.42s.

 

[stutaeng]

WOW 3.42?!

Well, if you can't upgrade to a 4L80e due to emissions, I would upgrade to a truck that has it. K2500 Suburbans had the 4L80e and came with 3.73 or 4.10s from the factory, not to mention a 9.5" semifloat or 10.5"full float 14 bolt. Plenty options as far as lockers for either of those 14 bolts. Better front axle 9.25". Larger brakes all around also. Depending on the engine, hydroboost brakes. The 4L80e transmission alone is worth the upgrade if you ask me. Save your new crate 5.7 for it and sell you 65e. You won't have to invest much on "upgrades" on that platform.

By the time you spend all the money on regearing both axles, rebuilding a transmission for the 4th time, you've have spent more money than upgrading the truck...

 

[alpinecrick]

Curt,
TruCool website does not specifically say those Max Coolers are LPD, but does with the other coolers. Somewhere I asked this question and was told they are not LPD. I guess a call to TruCool would be the only way to confirm.

3.42 gears probably means your TQ is unlocked more often and (importantly) slips more when not locked--for sure that will generate heat.

I ain't smart enough to figure it out myself, but I've wanted a light somewhere on the dash to tell me when the TQ is locked/unlocked. It's easy to tell when in OD and flying down the highway, but a lot harder when driving in varying speeds in 3rd and OD.

 

[Curt]

WOW 3.42?!

Well, if you can't upgrade to a 4L80e due to emissions, I would upgrade to a truck that has it. K2500 Suburbans had the 4L80e and came with 3.73 or 4.10s from the factory, not to mention a 9.5" semifloat or 10.5"full float 14 bolt. Plenty options as far as lockers for either of those 14 bolts. Better front axle 9.25". Larger brakes all around also. Depending on the engine, hydroboost brakes. The 4L80e transmission alone is worth the upgrade if you ask me. Save your new crate 5.7 for it and sell you 65e. You won't have to invest much on "upgrades" on that platform.

By the time you spend all the money on regearing both axles, rebuilding a transmission for the 4th time, you've have spent more money than upgrading the truck...

Yeah, call me crazy but I love this particular truck to death... more on that in my build thread. Only reason I'm sticking with it is because of the nostalgia I have with it. I'll put it this way, if I got rid of this truck I wouldn't be sticking with this platform. I'd upgrade to a newer 2500/3500 k2xx diesel and be done with it. But, I plan on keeping this truck and handing it off to my kid someday so I'm willing to make things work.

Curt,
TruCool website does not specifically say those Max Coolers are LPD, but does with the other coolers. Somewhere I asked this question and was told they are not LPD. I guess a call to TruCool would be the only way to confirm.

3.42 gears probably means your TQ is unlocked more often and (importantly) slips more when not locked--for sure that will generate heat.

I ain't smart enough to figure it out myself, but I've wanted a light somewhere on the dash to tell me when the TQ is locked/unlocked. It's easy to tell when in OD and flying down the highway, but a lot harder when driving in varying speeds in 3rd and OD.

I'll have to give em a call and confirm. I'm not saying anyone is at fault here but I do find it intriguing how their box advertises it as a LPD cooler. Either ways, I love the idea of a thermostat on the transmission so I'll be adding one regardless.

I typically tow in 3rd unless I'm going fast enough to lock the TC. Found out the TC locks at about 50 MPH while giving it 5-10% throttle on flat grounds. Kept the trans happy at 180F on the way home (keeping in mind I already cooked the fluid prior to going back home). Probably the only reason why I made it home a couple nights ago.

I do have a question regarding the pan though @alpinecrick, do you use the regular 4L60e filter or do you use the deep pan 60e filter?
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EDIT: I really appreciate everyone's input here. Thank you everyone for your time and help! Going to be ordering parts in the next couple days and that list has been improved thanks to you guys.

 

[L31MaxExpress]

Did you replace the radiator when you replaced the failed transmissions? The debris from a failed trans ends up plugging the cooler. I would replace the radiator if you have not done it and fit the M7B. Also ONLY tow in 3rd gear not OD. Also delete the PWM function on the torque converter. The added slip from PWM will cause the trans to run hot. PWM can be deleted mechanically with a revised PWM valve in the valve body.

FWIW I have 5.13 gears, LT285/70R16s and a 4L85E with a shorter overdrive and still run 85-90 mph for hours at a time on the highway. Fuel economy is really no worse than it ever has been. Still see 17-18 mpg running 75-85 mph turning about 3,400 rpm @ 85. When I had 3.42 gears and stock size P235/75R15s I tested it once at 70-75 mph and I got the same mileage in 3rd gear at 3,000 rpm as I did in OD at 2,000.