My wife's '94 K1500 Suburban 350/4L60E has an external transmission cooler on it the same size as my engine oil cooler. My K2500 HD 6.5/4L80E has an external transmission cooler about half that size. Does anyone here have the larger cooler from the factory on their 4L80E? The fittings are the same, so I'm thinking seriously about buying the larger one to put on my truck for added cooling. I've only ever seen the small ones on the 4L80E, though and wondered why that is.

Can anyone help on this?

SnowDrift

If anyone is unclear on what I mean by "small" then you can check out Canadian Rigger's post under "Cowl Induction." He's got a photo of the front on his truck with the same setup as my truck. Small cooler on the passenger side is the tranny cooler I'm referring to.

I've had both 4l60 and 4l80 and IMO the 4l60 is junk (700R4 with new name) and more prone to overheating and heat damage than the 4l80 which is essentially a turbo 400 with overdrive. This is why I think the 4l60 might have and need the larger cooler.

Tru-Cool is the trade name of coolers sold by the company that made the coolers (Long Mfg) used on our trucks. I used the H7B model for my tranny cooler and it really has worked well. I was able to re-use two mounting holes by using this brand, and I believe they also make coolers for B&M.

I never exceed 175F on the hottest summer days, but will qualify by saying I have not towed heavy loads in the heat either.

Try this link for Tru-Cool coolers:

http://www.bulkpart.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=2&Category_Code=tru-cool-ind

Thanks.

I'll take a look. For those prices, it may be worth it to switch if it's the same thing. The OEM cost is about $125, if I remember right. What about the fittings in the bottom for the line clips? I see these are NPT fittings.

SnowDrift

I just put the 25000# Tru Cool cooler on my dually. I found the stock one wasn't up to the task when hauling some heavy loads on my trailer in the summer heat. The new one fills up the entire grill opening on the pasenger side and so far seems to be way better. I haven't hauled anything yet but even normal driving now the temp hasen't been above 160. I am going to haul the car to a show on Fathers day about 120 miles from here so I will know exactly how much difference it made then. Oh, and the cooler only cost me $75 CAD brand new in box from an auto parts store! Cheap upgrade IMO.

With respect to the fittings, the OEM units are an odd size. I simply cut the metal pipes and used hose to connect it. I put nipple adapters into the cooler with #1 or #2 Permatex on the threads and there haven't been any leaks. I think the HB7 provides about 29000 btu heat rejection.

I didn't have to cut a thing! Just pulled the circlip from the fittings and was able to pull them right off the lines I think. Now i am going to have to go and look again. Didn't cut anything though. And on the trip yesterday, I managed to get it up to a whopping 170deg on a real long hard pull. With the factory cooler, that would have been in the 230 range for sure.

Ok, then. Tell me more - if you didn't cut anything, I'm interested. Got photos?

Didn't cut a thing. All you have to do is slide the new hoses over the hard lines that went to the old cooler and secure them with hoseclamps. I don't have any pictures but was thinking of doing the old "cleaning of the cores" this weekend. I'll take some when I do that if you'd like. One thing, it was a bit of a strugle to get the hoses on due to the position and the soft part of the other lines, but I was able to get em on with a little strugling.

Yeah, I would like to see photos if you wouldn't mind it. Would the install be easier if the valance was removed between the grill and the bumper or was yours already removed? Looks like I'm going to be replacing tranny oil cooler lines shortly, too. I have one starting to leak that I noticed when I was replacing the engine oil cooler lines.

Thanks!

SnowDrift

Sorry, didn't get to it this weekend. You know how the old honey-do list goes.:rolleyes: I did look at the fittings and stock cooler though to refresh my memory. The fittings thread into the cooler and are held in place on the hard line end over a flare on the line about 1/2" down the line with a little clip that slide through the threaded fittings that go to the cooler. Kinda like how the oil cooler lines are attached to the block by the filter adapter.