GM Trans cooler

rocksolid · April 14, 2001

My truck did not come with one stock,can I get one online for a good price? I would like to go with a GM cooler.

Thanks.

MountaineerTom · April 14, 2001

If you can get the part number, try gmpartsdirect.com They seem to have good prices. I've never ordered from there though.

(Edited by MountaineerTom 99Z71 at 11:01 pm on April 13, 2001)

Shaners · April 15, 2001

Rock solid,

My truck did not have one on it when I bought it. I tow so I thought it would be best if I went with the factory cooler, and I wanted the dealer to install it for me for obvious warranty related reasons. I think he did itfor around ? installed. I'll double check my sales slip later on and let you know if I'm wrong on the price I paid.

2k1 2500hd · April 17, 2001

I had a trans cooler added to my 95 Blazer by the Dealer. They used an aftermarket cooler I don't remember the brand. I was told by the service writer that it was far superior to the factory one. I did a compare a couple of years later with my 97 2500 and he was correct the after market was much larger with larger cooling coils.

Also be aware that the fluids in the transmission sould go from the tranny to the factory cooler in the radiator then to the external cooler then back to the tranny. This helps to maintain the fluid at the proper working temp (not to cool).

CapnDean · April 23, 2001

Bruce: Please clarify "Not too cool".

The routing you suggested (which I agree with) would provide the greatest amount of cooling possible.

Example: If your fluid went from the tranny, through the aftermarket cooler, through the radiator's tranny cooler then back to the tranny..it could conceiveably be "re-warmed" by the radiator.

If you go as you suggested it would be the coolest it could be upon return to the tranny....so why would you worry about it being "too cool" and if so...wouldn't you route it the other way if you thought that might be a problem?

2k1 2500hd · April 23, 2001

This is long, so bear with me.

Transmission fluid is designed to give the best hydraulic properties at a certain temp (not sure what the temp is). If you run your fluid straight from the tranny to the cooler (bypassing the radiator) and its really cold outside your fluid will never reach the proper operational temp. Running through the radiator warms the fluid up before reaching the cooler and helps it retain the wanted heat. Also, I think it's also like engine oil, you want it at a certain temp to boil off an moisture from setting over night. Auto tranny's are not 100% sealed, so moisture can get in.

You have to remember that an external cooler really only does good if you are pulling or hauling a load other then that it's not really needed.

There are aftermarket coolers that have temp controlled bypasses, so the fluid does not go through them unless the fluid reaches a certain temp.

CapnDean · April 23, 2001

Bruce: I respectfully disagree. I agree that the properties of hydraulic fluid are such that temperature is a factor in their viscosity. It is my belief that unless you are freezing your fluid in a tranny cooler (which incidentally would require an OAT of about -20 degrees) by driving so fast in such cold climate that the transmission could not produce enough heat to overcome the "chilling" effect of the wind across the vanes.

Keep that fluid cool....the cooler/the better!

Question for the board (for those Canadian Geese and Cold Climate follks)...Has anyone ever experienced frozen transmission fluid in an auto trans vehicle?

2k1 2500hd · April 23, 2001

CapnDean, you are more then welcome to disagree. This is what makes these discussions worthwhile and generates more interest in the topic.

I thought I was going to have a devil of a time backing up my statement. I couldn't find anything that would back me up. Then I found Hayden's transmission cooler site and found the answer under their FAQ.

I Quote: Q. Can you over cool the transmission fluid?

A. Transmissions are not highly sensitive to cool operating temperatures. However, in sub-zero (20-30° F) weather conditions transmission fluid can actually gel up in an external cooler and cease to flow, causing damage. Use of the radiator cooler actually helps warm the fluid under these conditions. It is critical in extreme cold conditions to use the original equipment cooler in series with the auxiliary cooler and allow the vehicle to warm up before driving. End Quote.

Their WEB site is located at:http://www.haydenauto.com/faq.html

I hope this clarifies my statement.

Also on several Oil Company WEB sites including Mobil and Valvoline the mentioned proper auto transmission operating temp but never mentioned that temp.

(Edited by 2k1 2500hd at 4:00 pm on April 23, 2001)

gmcblu · April 24, 2001

Somebody clarify for me: Are y'all saying is that I don't have to worry about overcooling it if I live in Central Texas (where the temp dips to the +20s a couple of times a year)?

CapnDean · April 24, 2001

I am saying that Bruce's suggested routing is correct and would provide the greatest amount of cooling possible which (unless you live at the north pole) is the goal of an aftermarket tranny cooler. E.G. The cooler the better.

Bruce's comment about "overcooling" the fluid is not consistent with the routing he suggested. I am saying that IF you were worried about over-cooling your tranny fluid THEN you should route the fluid from the tranny..to the after-market cooler then trough the radiator (to sorta warm it back up) and back to the tranny.

I am skeptical that in the USA we EVER have a region that gets sooooo cold that you would actually need to "re-warm" the fluid. If that were the case I'd just skip installing an aftermarket cooler.

This is a friendly disagreement here...I'm not rabid about it!

2k1 2500hd · April 24, 2001

CapnDean, I think you misunderstood my original post, or maybe I wrote it poorly. What I was referring to came on the paper work of the cooler I had installed on my Blazer. It stated that the cooler should be installed after the factory cooler in the radiator of the car. This helps maintain proper operation temp of the transmission while not towing. If the cooler is put on and completely bypasses the factory cooler the transmission will take longer to reach proper operational temp.

So in a nutshell all I was stating is that, using the radiator cooler in conjunction with the external cooler will help the transmission reach operational temp sooner.

(Isn't this fun, arguing (I know were not arguing) via fiber optics!!)

(Edited by 2k1 2500hd at 8:59 am on April 24, 2001)

2k1 2500hd · April 24, 2001

DUP Post

(Edited by 2k1 2500hd at 7:35 pm on April 24, 2001)

2k1 2500hd · April 24, 2001

rocksolid

To get back to the original supject of this post. One of the best ransmission coolers on the market is Hayden. All of the good RV shops use Hayden and alot of the car dealers here use them for after market installs.

There WEB site follows:http://www.haydenauto.com/

the coolers run somewhere between ? and ?.