A/C condenser into tranny cooler?

[donaldbaze]

So I ran into an idea what if run my tranny lines to the A/C condenser and turn it into a tranny cooler does anyone know if the flow would be to restricted for atf? And would it cause my tranny to run cold in winter if it does work? Anyone have any thoughts on this before I try it out?

[OldGreen]

Tons of people do it. . .seems to work fine. Try it and report back. I think that I would try and flare the tubes or figure some other way to connect it so that it doesn't come off at the wrong time and catch your Jeep on fire.

[donaldbaze]

Im going to swap out the tranny today and hook the A/C condenser up. Ill post some pictures after I am done. Hopefully ill have 2d gear again. I have never been able to drive my jeep in 2d gear.

[Lurch]

I've heard it was a bad idea but cant remember why right now. If you do try it make sure you flush all the oil and possible metal particles out of the condenser first.

[OldGreen]

Certainly have heard both ways, but there are a lot of Jeep 4.0 guys that do it and report good success. I think that I would put on a tranny temp gauge and keep an eye on it.

Actually. . .I wouldn't do it myself, but that's another story.

[79chevy39.5's]

havent on a cherocar, have on other rigs and worked better than bleeding atf into coolant, never had a gauge on it though

[donaldbaze]

Ive read both ways aswell. Ill put a temp gauge on and figure out proper fittings. Is.it possible to harm anything doing this? Or if i dont like it can run new lines?

[mattawajeep]

Do you not have the ports on the radiator? If your radiator is set up for ATF I'd run the fluid through the radiator first and then some sort of external cooler. That way your fluid won't run too cold, and you still get the added cooling.

I've heard that AC condensers get plugged up easier, but that was only anecdotal. If you're trying to be cheap, I'd go to the junkyard and see if I could find an actual additional tranny cooler out of a 3/4 ton truck, flush it out really well and use that instead of the AC unit. Transmissions are kinda expensive, if it were me, I wouldn't risk messing it up by using something that might not flow correctly.

Whatever you do, I'd stick a temp gauge on it.

[donaldbaze]

Thanks for the advice I think im going to get a different unit so i don't have to worry about it getting clogged. My buddie is going to continue and do this to Cherokee tonight ill let you know how that goes and ill post what i pick up for mine.

[Lurch]

I don't (and wouldn't) run mine through the radiator. The cooler a Trans runs the better. I actually have 2 external coolers on my wheeler. I also run a gauge to keep an eye on things. I would recommend the pickup for a gauge actually be in the pan. The test ports on the side of the case don't give very accurate temp readings.

[mattawajeep]

I don't (and wouldn't) run mine through the radiator. The cooler a Trans runs the better. I actually have 2 external coolers on my wheeler. I also run a gauge to keep an eye on things. I would recommend the pickup for a gauge actually be in the pan. The test ports on the side of the case don't give very accurate temp readings.

Where's yours been running with the second cooler added?

I've heard lots of numbers thrown around - but if you can keep your temps around 150 that's just about optimum. If things aren't staying colder than that when you're bypassing the radiator I'd say things are fine.

I don't know about the AW4, but lots of transmissions have a harder time shifting when the fluid is colder, and you get more wear, possible slippage, and some even say that water doesn't evaporate out fast enough. Probably not the end of the world, but that's what I've been hearing.

I think I have the same setup as Donald - 4.0 & AW4, although my stuff's in a TJ, probably not much different.

Running through the radiator, and then into an external cooler my fluid temps on the highway run right around 150 in the winter, and as high as 170 in the summer. Pulling hard up hills at highway speeds can get the fluid up to 190 on hot days.

Wheeling in 4-low, temps also tend to stay around 150, unless I'm doing something stupid, err fun, in the snow and am really laying on the gas.

[OldGreen]

Tidbit. . .

250 degrees is where the backing material separates from the clutch discs.

[Lurch]

As long as your under 230 you should be fine. I'm typically around 200-210 on the trail when I'm working it. Normal running around I would say 150-170. Typically the never need to run through the radiator to "warm up" there is enough friction and slippage in an automatic that unless your driving in cold temps with no load it should create plenty of heat on its own.

[donaldbaze]

I got the tranny swapped decided to throw in a different transfer case as well. I hope this solve the problem.

[donaldbaze]

Swapped out the tranny last night and still have the same issues. No 2d gear. I've changed the computers aswell. time to trace the wires down now.

[mattawajeep]

Swapped out the tranny last night and still have the same issues. No 2d gear. I've changed the computers aswell. time to trace the wires down now.

Have you tried messing with the neutral/shifter position switch? If there's a short or something in those wires it could lock the transmission into 1st until 4500 rpm.

[donaldbaze]

It was busted off previously and i put it back on. But if I put my jeep in drive it starts out in 3d gear. If i cycle 1-2,3,4 it only skips 2d. I have tried diffrent tranny computers and it shifts exactly the same plugged in or unplugged.

[mattawajeep]

It was busted off previously and i put it back on. But if I put my jeep in drive it starts out in 3d gear. If i cycle 1-2,3,4 it only skips 2d. I have tried diffrent tranny computers and it shifts exactly the same plugged in or unplugged.

Does it start in third gear with the computer completely unplugged?

Try unplugging the neutral/shifter switch and see what happens in drive. With it unplugged, starting in drive, you should be in first gear.

Also, it's pretty much always going to skip second if you're manually shifting. The only way it' hit second with the shifter in 1-2 is if you really wind up the rpms, which I wouldn't suggest.

[donaldbaze]

It runs exactly the same plugged in or not. Its almost like it dosent even register the tcu. But there is no possible way to get it to shift into second. I went to juniper last weekend without second and its crud. First is to slow for the big dunes and im sure its not good on my suspension to hit anything in 3d gear seeing as how I blew out 3 of my shocks. I've traced the wires back in my wiring harness and there all intact.

[bobracing]

Could always ditch the computer.

http://www.radesignsproducts.com/Rail.html

[White trash]

Could always ditch the computer.

http://www.radesignsproducts.com/Rail.html

The rail shifter is neat. I liked Rory's controller I ran too.



It's easy to test the solenoids in the trans. A trio of toggle switches will give you complete control of the trans. One dpdt - on/off/on and two spst - on/off switches. Run the power to the trans computer through one leg of the dpdt switch and power solenoid #1 off the other side of that switch. Power solenoid #2 with one of the other switches and solenoid #3 with the other switch.

Turning solenoid #1 on will give you 1st gear, if #1 is on and you power #2 thats 2nd gear.TTurning #1 off while #2 is powered is 3rd gear, if you then power #3 othat gives you OD by locking the converter. I ran #3 on a separate switch so the converter could be locked in any gear to provide compression braking.

[mattawajeep]

What WT said. Power the solenoids manually, and if things check out, you've probably got a wiring or computer problem.

If you can track down the computer problem something like this is also an option:

http://montanafab.com/products/

Though it seems to have gone up in price since I bought mine. It'l let you keep the computer, and turn it off at will so that you can manually select your gears, all without triggering a check engine light.

[donaldbaze]

I have already wired in the switch, it dosent do a single thing. im sure its wired ir correctly. its like my jeep wont register the tcu?

[White trash]

You unplug the computer completely and power the solenoids directly and it will shift. If not you have a solenoid issue. The odds of there being a bad 2nd gear solenoid in 2 trannies is slim though so I'd focus on the body harness.