Transmission Cooler AND Engine Oil Cooler?

[camper1999]

This brings up a related topic, changing the trans fluid frequently. Most manufactures state trans fluid does not need to be changed until 100,000/50,000 miles. but depending the operating temp it may need to be done way sooner. Some said adding a trans cooler is cheap insurance so is changing the trans fluid. If you frequently run above 175 degrees requires more frequent changes

[SKnight]

Originally Posted by BadgerRoo

You reccommend the older tube and fin type coolers over the newer and supposedly more efficient designs?

Yes, to a degree. Hayden coolers have turbulators inside the tube that causes the fluid to spin inside the tube, that results in the fluid exchanging heat very well, nearly as well as a newer design flat stack cooler. They're cost effective as well.

Would a Hayden 678 or 679 be better? Sure. Worth the added cost, in this case I think the added cost is unnecessary.

He'll be fine with either one honestly.

[BadgerRoo]

You guys are great! Just want to clarify/get a consensus on how often the tranny fluid will need to be flushed/exchanged after I add the aftermarket cooler..

Does it really need to be flushed every year, or just more regularly/frequently? My local GM dealer charges $169.95 complete fluid exchange (included torque converter), install conditioner, and synthetic fluid replacement. I'm not cheap by any means, but $170/every yr. is definitely something that I want to make absolutely sure is 100% necessary.

[BadgerRoo]

Yet another question!

My GM service center can install the cooler any time next week (I'm supplying them with the aftermarket cooler and they're fine with that). Given that we're still in winter here, should I wait until the spring to do this? Will the winter temps hurt the new cooler at all?

[checca]

Originally Posted by BadgerRoo

Yet another question!

My GM service center can install the cooler any time next week (I'm supplying them with the aftermarket cooler and they're fine with that). Given that we're still in winter here, should I wait until the spring to do this? Will the winter temps hurt the new cooler at all?

Do it now ... will not hurt.

[checca]

Originally Posted by BadgerRoo

You guys are great! Just want to clarify/get a consensus on how often the tranny fluid will need to be flushed/exchanged after I add the aftermarket cooler..

Does it really need to be flushed every year, or just more regularly/frequently? My local GM dealer charges $169.95 complete fluid exchange (included torque converter), install conditioner, and synthetic fluid replacement. I'm not cheap by any means, but $170/every yr. is definitely something that I want to make absolutely sure is 100% necessary.

I think not about the $170 a year ... but over 10 years it's only $1700.00, still less than a transmission and much less of a head ache after a break down.

[Mtelkman]

Blackstone Lab will test your oil and tell you if it needs changing for about $25. No way I would spend $170 a year to change oil that might be perfectly fine.

The reason you should change the fluid when you put the new cooler on is that you may have overheated the old oil. Oil breaks down w high heat. Start fresh with new synthetic and have it tested after a year and see how it is doing.

[BadgerRoo]

Originally Posted by Mtelkman

Blackstone Lab will test your oil and tell you if it needs changing for about $25. No way I would spend $170 a year to change oil that might be perfectly fine.

The reason you should change the fluid when you put the new cooler on is that you may have overheated the old oil. Oil breaks down w high heat. Start fresh with new synthetic and have it tested after a year and see how it is doing.

I may get blasted here.. but.. I'm getting the aftermarket cooler installed next week by my GM service center and do not think I'll be getting a full trans fluid exchange at that time. I only towed my new camper once a few weeks ago (home from the dealer) and my transmission temp never got above 170 degrees F and was usually in the 150's; not to mention I never get above 120 degrees F without towing. My vehicle barely has 40,000 miles on it and has runs on synthetic trans oil already.

I think I'll be fine if I get it fully changed out at the end of next winter in approx. a year. Wouldn't you think so?

And thanks for the blackstone lab idea, appreciate it!

[AquaMan]

Originally Posted by BadgerRoo

3) So if I have both the transmission cooler and engine oil cooler installed but stick with the 3.08 rear axle, would the math still work out; that I would maybe have 7,500 lbs towing capacity since my manual states increasing from a 3.08 axle to a 3.42 only gives me 500 lbs more trailering capacity? Or does it not "work like that" with trailering?


Thank you all for your time and sorry for the novel!!!

I would say it doesn't work like that. The COMBINATION of the ratio and coolers is what raises the capacity to 8000lbs. The addition of just one of these would still only give you maybe 500lbs capacity.

[SKnight]

Originally Posted by BadgerRoo

I may get blasted here.. but.. I'm getting the aftermarket cooler installed next week by my GM service center and do not think I'll be getting a full trans fluid exchange at that time. I only towed my new camper once a few weeks ago (home from the dealer) and my transmission temp never got above 170 degrees F and was usually in the 150's; not to mention I never get above 120 degrees F without towing. My vehicle barely has 40,000 miles on it and has runs on synthetic trans oil already.

I think I'll be fine if I get it fully changed out at the end of next winter in approx. a year. Wouldn't you think so?

And thanks for the blackstone lab idea, appreciate it!

Odds are your fluid is fine right now, and you're coming up on a regular change interval since I think you're on a 50,000 mile schedule with the syn. I'd get it changed at the normal mileage when you reach it.

The yearly thing is mainly to get people to think about it. Is it best? Yes, truly necessary? Not at all. The big concern is if it sits a lot and isn't run regularly. That allows the oil and detergents/additives to separate, moisture to condense and never get burned off, etc. That's where the yearly comes to play.

As for the future, once you get your change done at a regular interval if you tow a lot I'd keep an eye on it and change a little early, I'd subtract your towing mileage from the interval. For example, if the interval is 50,000 miles as I suspect and you tow it 10,000 miles over that interval then I'd get it changed at 40,000 miles, up to half the interval or 25,000 miles. Even at 40,000 miles that's still two or three years if you're an average mileage driver.

And I'd still look into the oil cooler, engine oil is very neglected and the lines and all won't cost that much.

[beerjay]

Originally Posted by AquaMan

I would say it doesn't work like that. The COMBINATION of the ratio and coolers is what raises the capacity to 8000lbs. The addition of just one of these would still only give you maybe 500lbs capacity.

Yes, I looked at the 2012 Towing Guide (on Trailer Life site).

The 2012 Yukon XL 1500 4x4 with 3.08 is rated for towing 5000 lb. You may not gain anything with the trans cooler. Best to call a GM service place and check ...

Suburban/Yukon XL 4WD 5.3L V-8 5,000 (b) 3.08

Suburban/Yukon XL 4WD 5.3L V-8 5,500 (g) 3.42

Suburban/Yukon XL 4WD 5.3L V-8 8,000 (g,p) 3.42 plus trans cooler

[thebrakeman]

A 1 hour trip on the highway (convertor locked, no trailer, lots of air movement) is not going to give your worst case non-towing trans temp. Get a look sometime when you've been running errands around town, with a decent amount of shifting.

Also, your original post says you have no trans cooling. Not entirely correct. All (nearly all?) automatic transmissions will have a cooling line running the engine coolant radiator, where it will flow thru a bulb-type cooler. The engine coolant circulates around this bulb.
a. When you start the truck on a cool day, the engine coolant will warm up before the trans fluid, so this will help the trans coolant come up to normal operating temp quicker.
b. When trans is getting worked hard, it works the other way. The engine coolant has been cooled by the air flow, and in-turn is able to cool the trans fluid.

You need some auxiliary trans cooling, which will allow the fluid to run thru both coolers. There is debate over which order they should flow. I would say run thru the air-cooler, then the bulb cooler, then back to the trans.

[Platokidd]

Originally Posted by thebrakeman

A 1 hour trip on the highway (convertor locked, no trailer, lots of air movement) is not going to give your worst case non-towing trans temp. Get a look sometime when you've been running errands around town, with a decent amount of shifting.

Also, your original post says you have no trans cooling. Not entirely correct. All (nearly all?) automatic transmissions will have a cooling line running the engine coolant radiator, where it will flow thru a bulb-type cooler. The engine coolant circulates around this bulb.
a. When you start the truck on a cool day, the engine coolant will warm up before the trans fluid, so this will help the trans coolant come up to normal operating temp quicker.
b. When trans is getting worked hard, it works the other way. The engine coolant has been cooled by the air flow, and in-turn is able to cool the trans fluid.

You need some auxiliary trans cooling, which will allow the fluid to run thru both coolers. There is debate over which order they should flow. I would say run thru the air-cooler, then the bulb cooler, then back to the trans.

If Im not mistaken, all my GM's runs from the trans to rad tank cooler to the air cooler then back to the tranny.

[BadgerRoo]

Originally Posted by Platokidd

If Im not mistaken, all my GM's runs from the trans to rad tank cooler to the air cooler then back to the tranny.

Yeah.. that sounds right (I think!) if I remember what I read recently.. anyway, if that is indeed the order of things; where would you recommend running the trans cooler lines?

Am I wrong to assume a GM service center (which is installing my aftermarket cooler next week) should be smart enough to know where the best place to install the lines would be?

[BadgerRoo]

Originally Posted by beerjay

Yes, I looked at the 2012 Towing Guide (on Trailer Life site).

The 2012 Yukon XL 1500 4x4 with 3.08 is rated for towing 5000 lb. You may not gain anything with the trans cooler. Best to call a GM service place and check ...

Suburban/Yukon XL 4WD 5.3L V-8 5,000 (b) 3.08

Suburban/Yukon XL 4WD 5.3L V-8 5,500 (g) 3.42

Suburban/Yukon XL 4WD 5.3L V-8 8,000 (g,p) 3.42 plus trans cooler

Yeah, I'm plenty aware of the vehicles towing limitations, and I'm comfortably under those with what I'm towing, I just want additional piece of mind with the trans cooler. On a different RV board there are several posters with the exact same 2012 Yukon XL 4X4 I have with the same 3.08 rear axle as well as an aftermarket cooler added, and they're towing much much larger TT's. I'm not agreeing with that being wise, I'm just hoping to eliminate a little bit of the stress and "white knuckling" when towing in this upcoming and hopefully hot summer, and not necessarily looking for increased lbs I can tow.

[Platokidd]

Originally Posted by BadgerRoo

Yeah.. that sounds right (I think!) if I remember what I read recently.. anyway, if that is indeed the order of things; where would you recommend running the trans cooler lines?

Am I wrong to assume a GM service center (which is installing my aftermarket cooler next week) should be smart enough to know where the best place to install the lines would be?

GM will know how to do it. I did my own on my 98 Silverado. The hardest part was removing the grill. Other then that the kit came with the lines to run.
Can of corn job took me about an hour.

[BigTJohn]

I put a Hayden trans cooler on my 09 RAM 1500 when I had my Grey Wolf. Before install trans temps were high - 200-250 and up. after that I installed the Hayden changed/flushed fluid and never saw temps above 170. Those temps were same VA/TN hills same time of year, etc. not scientific but enough data for me to know the trans cooler is a good thing

[BadgerRoo]

Originally Posted by BigTJohn

I put a Hayden trans cooler on my 09 RAM 1500 when I had my Grey Wolf. Before install trans temps were high - 200-250 and up. after that I installed the Hayden changed/flushed fluid and never saw temps above 170. Those temps were same VA/TN hills same time of year, etc. not scientific but enough data for me to know the trans cooler is a good thing

Hey, thanks for the response BigTJohn! Would you (or anyone else reading this) recommend I get a full flush/fluid replacement done when the GM service center installs my Derale tranny cooler this Wednesday? I'm currently at about 45,000 miles on my 2012 GMC Yukon XL and my manual says to change the fluid at about 97,500 miles; so I'm well before that. I've only towed with truck a couple times and the tranny temps never got above 175 degrees (granted this was in winter).

I don't mind spending the extra $170 to have this done if it is strongly recommended; but if it's a matter of personal preference only, I'd like to save the $170, too.

Thanks!

[SKnight]

97,500? Wow, they're really stretching it out.

If the fluid looks and smells good, then leave it be. They'll have to add a couple of quarts when they add the cooler so you'll get some fresh then also.

[BadgerRoo]

Originally Posted by SKnight

97,500? Wow, they're really stretching it out.

If the fluid looks and smells good, then leave it be. They'll have to add a couple of quarts when they add the cooler so you'll get some fresh then also.

Yeah I was a little surprised too considering older models of the same vehicle had their manuals recommend doing it at 45,000 miles, but mine says 97,500. I'm thinking maybe it's because of some higher grade synthetic fluid they may have started adding to the 2012's and up?