transmission cooler

not sure what is best . But on my 04 3500 they told me to change the cooler fluids at least every 12 to 15k....does that sound right? Have a Great One ! Bob :)

I've been told the plate-style coolers are more efficient. (not the ones with the round tubes running through the skinny fins)

They usually get mounted a few inches in front of the radiator or AC condensor, behind the front grille.

-marc

Yup.

GMC Gremlin

As far infront of the radiator & AC condenser as possible. I have a tube type, it was the largest offered by AutoZone in the manufacturer that TranSurgeon recommended.

GMC Gremlin

The farther away from the radiator the cooler is mounted the less efficiant it is at lower speeds and durring a stop its efficiancy could drop to zero! With the cooler mounted directly against the radiator(with a half inch dence foam cussion) it will have awsome cooling efficiancy durring a stop because the fan will be pulling air through it. A trans can really heat up durring a stop and slow town driving! Like the quote goes, Heat is the enemy or your transmission!

I have been told by auto trans Gurus that it is impossible to have too big of a cooler for a GM trans. There are exceptions to every rule, but its a good place to start!

Install the largest radial flow cooler that you can sensebly install against your radiator. If you instal its own small elec fan with a thermostatic switch, all the better!

I like that fan idea. But if you mount it that close the radiator your just going to pick up engine heat.

GMC Gremlin

five words: heat from the AC condenser

what good does a 'cooler' do if it's crammed against a condenser that can reach 300 + on a hot day ?

if you're directly against the radiator, the cooler can pick up heat from the engine, if it's against the AC condensor, it's even worse as they can get well over 300F on a hot summer's day.

on my truck I've got a Hayden Ultra-Cool 404 mounted about an inch or so in front of the AC condensor. the in tank cooler is also bypassed. around town, my trans heats up to about 100F-125F on my autometer temp gauge. the warmest I've got it was 210F going up and over Jellico Mountain (20 miles stretch between Jellico, TN and Caryville, TN, 4% grade for 10 miles) 8 times a week during July - august of this year. even with the cooler mounted away from the condensor, there is SIGNIFICANT airflow through it, even at a stand still.

-Bret

What did you guys say about how often you need to change the trans fluid with an oil cooler? 12-15k?

'normal' (everyday driver) use :12-15k occasional towing or heavy loads 10-12k everyday loaded ('work' truck) 8-10k heavy loads all the time 5-8 k

with heavy loads or towing more than half the time, I'd use 50-50 mix of ATF and MobilOne 5-20 engine oil

My Dealer told me every 12-15 the External trans cooler fluid should be changed on my 04 Duramax 3500.... Have a Great One ! Bob :)

Gary, I have a large Hayden (forget #) cooler I installed in my 1990 F/S Jimmy w/ TH700R4 bypassing the OEM "cooler". I was thinking of attaching another one in parallel, as you would for a heavier duty application. Would a 50/50 mix be bad for a daily driver that never tows, but occasionally gets the living piss kicked out of it?

GMC Gremlin

so when you say external transmission cooler, that means like the trans pan filter along with the fluid, minus whets in the torque converter? right now I change the fluid in my truck every 35,000 miles like my owners manual says for normal driving conditions. Why would it be less with an oil cooler. I'm confused. Forgive my ignorance.

Kiel Uyttenhove

one large Hayden is plenty for a 700

and go ahead with the 50-50

radiator(with

because (ready ??)

fluid costs a lot less than an overhaul

Well my Silverado has its own trans cooler, and the owners manual says the same on that unless its being driven hard. I've done this since I have owned both my vehicles with less then 35,000 miles and I never have problems, I'll stick with what works for me.