Autobox Cooling questions

[jcasey007]

Hi All

I've just come back from vacation where we were fully loaded and towing a folding camper over 2 weeks we covered nearly 3000 miles in France.

I prepped for the tranny with Synthetic ATF (AIMOIL) and fitted a transmission temp Guage.

There were a few times when I had some concerns on the temp especially on long uphill drags when the temp would spike at about 80 degC. At one point it hit 85 degC and the tranny went into 'limp home' (it would not allow top gear) a cooldown and a restart saw the error and problem go away.

So I'm going to fit an aux oil cooler to the tranny and have a couple of questions..

I'm going to fit a big one but is over cooling just as bad for the transmission?

What pressure is the oil being pushed through?

The standard oil cooler is being cooled (or heated?) by the water in the main engine radiator, Can I disconnect it and just run my aux cooler in the air? The water is at about 87 degC, if I'm trying to keep the transmission oil at 60 degC will I be fighting against it.

cheers

Jim

 

[Maniak]

Yes, overcooling can be bad for the transmission.. But..

I "think" your 1997 is new enough to have the thermal bypass in the transmission. That means it doesn't let the fluid go to the cooler (in you case, the radiator) until its warm "enough". Hopefully someone can post if I remembered that right (can't remember what year they started that)

Having an aux cooler only (bypassing the radiator) is still up for debate. There a are a couple rules of throught on it. Most external transmission cooler just aren't big enough to cool the fluid by themselves. Also, depending on what temp your transmission is the radiator temp should still be cooler than the transmission fluid temp as it comes out of the converter. Therefore it (radiator) is still cooling the transmission.

If you put on a nice sized transmission cooler it should definatly help. I'd go with the biggest one you can fit behind the grill But remember you will be putting something "hot" in front of the radiator and the a/c condensor which will put some more heat into the radiator (hotter air). Also, The farther forwards the cooler is the less air the radiator fan will pull through it.

I hope that helps more than it confuses....

~Mark

 

[jcasey007]

OK so I will leave the OEM cooler in place.

This is what I'm thinking of fitting (240mm wide, 10 row high) it's about the biggest one I can find at the moment in the UK, but will keep looking tonight.

out of interest how big is big?

cheers

jim

 

[Maniak]

The biggest one I have found is the one I'm using on the tow rig. It is used as the only cooler and it keeps the pan temp of the c6 (somewhat cool running trans anyway) 160F or less even when towing up hill. Tow rig + trailer plus what I was towing came out to around 13k lbs.

Here is the cooler I"m using there.
Tru-Cool # LPD47391 40,000 GVW rating, 45,000 BTU rating
8 1/2 x 22 3/4 x 1 1/4 inch

Here is a pic of it. I "think" it might be a little big for an explorer. Its pretty wide and is 1.25" thick.

On our 1st gen X, I'm running two trans coolers. IIRC one is a 30k gvwr and the other is a 24k gvwr.. The fan is from a 92 Geo Prism/toyota corolla (a/c fan).

Its the most I could fit in there..

Most trans cooler I see in auto parts stores are < 15k gvwr coolers. It would help, but no where near enough to be the only cooler.

~Mark

 

[willindsay]

I know I'm bringing up a kinda old thread but I'm lookin for some info on wiring a pusher fan up. I picked up the same fan as you Maniak as I saw you recommend it to RookieShooter in his thread.