OT Truck transmission cooler

Same old problem: Tranny heat. :>)

Yes Sir, to my mind there is only ONE axillary transmission cooler for your truck and that is the one from GM. If you have one of those "hayden" or other after market types sold by the auto market parts stores, in my view, you are flushing your money down the toilet; they just don’t have the cooling capacity even though they are physically bigger. Just my view. :>)

The "absolutely essential" external cooler (for towing) should be inserted AFTER the radiator and just before the transmission’s "in" port.

The way those things work is that they take the transmission's lube oil and cool it, then return that lube oil to the reservoir.

The only enemy an automatic transmission has is heat; and at 305 degrees, the adhesive holding the clutch material to the plates starts to melt and lets the friction material go. So, I try not to run a tranny much over 270 degrees to be on the safe side. A transmission temperature gauge is a good idea if you tow a lot.

The reason your friend says that they do not work in the cold wintertime is not because they do not heat up; they will, that tranny always runs at better than 200 degrees. Just running down to the post office is going to heat up that tranny.

Rather, it is because when first started in the wintertime, that cold oil is thick. If the cooler is not plumbed into the system right, the pressure will blow the hoses off even though that lube pressure is only 7 lbs; it is unforgiving; it has to go somewhere.

Always use steel line on a transmission cooler connection and never, ever use rubber hoses and clamps.....they don't work in cold climates and will result in a failure.

Hope this helps you a little,

Allan

I like to use either 5/16 or 3/8" steel brake lines (depending on the transmission), cut to length and use double flared or stout compression fittings to tie in. If you want to gauge the temperature of the transmission oil, grab it at that ‘out’ port of the tranny. This is where it is the hottest.

Like I was telling Bob, I used to rebuild up there in North Dakota. They have some very high temperature summers and the winters are at the opposite side of the coin, often at 30 below or better for weeks on end.

Those guys are experts on towing with automatic transmissions; they see both sides of the question.

Allan

Boy, I'm not gonna get in a screamin' match with ya, but that just isn't the way of the real world.

Why would you spent upwards of $300 for a decent cooler and then have it's product reheated back up to 205-210 degrees (15 degrees from the safe upper operating zone)? This routing method is defeating it's purpose altogether, to my mind. ????

Automatic transmission oil is a contact sport; if it is there, it's gonna lube. The trick is keeping it where it belongs and not havin' it blowin' out that vent due to heat.

This is just my humble opinion and stated as such.

Regards,

Allan

Also whenever there is a transmission failure which produces metalic trash some of the trash ends up being stuck in the cooler. This metalic debris works it way loose and will eventually destry a rebuilt tranny. The best thing to do is to replace all coolers and blow out the lines when doing a trans repair.

Boy, we're just disagreeing' all over the place, but that's okay, it would be a very dull world if we all thought alike.

About that 350 crackin' the case. Sure wasn't from pressure that's for sure and this is because of two reasons: that regulator dumps at 62 lbs (or thereabouts) thru a port as big as your manhood. When cold, getting oil thru that paper filter is a task in it'self and applying the low/reverse clutch when cold is always “slow” because of this ‘lower’ pressure.

Regulated pressure will not run higher than rated line pressure, no matter the temp, because if it did you would never have a shift. This is how the silly things work.

Trucks were very hard on that anti-clunk spring allowing it to "work". This wore the case away at the center support’s indexing land. Soon, the snap ring could no longer hold the center support in place and bang, there she goes.

Also, most of the cracked 4x4 cases were because that big strut rod was not in place. Hit a restriction or a hole with that right front wheel and and you’ve got that front drive shaft right in the tranny’s lap. It had to crack, no way around it.

Just my next disagreement, have a good one, :>)

Allan

Yes Sir, so true.

That's why early, early on I made my mind up to absolutely know what was wrong with an oufit just by listening or driving the unit, before I ever walked over to the tool box. I never wanted to just "guess" at a repair. That is just not fair to the owner.

I would suppose you do this too; to know any given system's operational ins and outs like the back of your hand. Just makes the darned jobs go so much eaiser, but it takes a little more studing is all.

What kills me is these guys that throw parts at something 'til they finally hit on the cure; what a waste of money and time; and guess who pays for it, the poor customer! :>)

Nice talkin' to ya Buddy, I really enjoyed visiting with you. What part of ND do you live? Maybe I know you. :>)

Allan

You are correct about the 2 ways being suggested to plumb in the cooler. However, in the real world, either one works out about the same.

You want a good-sized cooler that's not too restrictive, though. What you are doing is cooling hot oil leaving the torque convertor, and the return from the cooler supplies the lubrication circuit in the tranny, lubing bearings, bushings, and thrust washers and needle thrust bearings.

How's thing going up there in the great ND, anyway?

Spent many a day up there, keepin' those auto trannys moving for the oil patch boys in your summer heat. That state will test any tranny! :>)

Later,

Allan