Coyote Kid

Having problems with my tranny overheating, the Toyota service Tech thought all was good (no kinks or plugged up) and suggested use of an aux cooler because "aftermarket radiators don't always have same cooling capacity as original" he said. The tranny has probably 200K+ miles (I say probably because the OD shows 127K, but after buying this I realized too late that certain things just didn't add up, and a car fax report confirmed something was not right -I know, shoulda got that BEFORE I bought).

Sooo, my question is, how hard is it to install an aux cooler myself (doesn't look like a lot of space in the front of the radiator) How does it tie in with the existing lines/cooler? What specialized tools might I need?

Tubbyfatty

Ive seen rads that have tranny coolers in them, looks just like a normal rad. But its not. lol.

Im sure you can do it, if theres already lines ran for cooler its really simple. Well im sure its already easy, just running lines from the tranny to the rad/cooler, then adding more fluid to fill those lines.

Someone feel free to add on what i said.

91diesel

I just did it and it's easy, just like Shawn said, take the return line, mine was on the driver's side of the rad, run a line up to a cooler, (mounted some where up front, or you could use the skid plate) and then back to the return to the tranny. All you need is some hose clamps and a screwdriver and a knife.

Coyote Kid

Bypass the old rad? or tie it in for additional cooling? If so, how to do that, just a T fitting or Y fitting of some kind? And any recommendations on a brand /size/ with a fan or not?

space-junk

iTrader: (1)

auto or maual??

i thought that the autos already had tranny cooler lines ran to the stock radiator...

91 4Runner

Autos do have a tranny cooler on th epassanger frame, but the cooling is marginal at best. Add larger tires and trannys will start to die...

Run the aux cooler in series with the factory. There is plenty of room on the rad to mount the aux cooler....

Mic09dcsm

Best solution, swap in a manual transmission.

James Dean

2nd gen auto's have a cooler in the bottom tank on the radiator. If you have any kind of add on to your bumper it can lesson the amount of air that cools the tranny. These trannys are already on the virge of overheating, and like mentioned if you add tires, a lift, lights or high mileage, etc it can push it over the edge. First time on the freeway with a load mine was puken fluid and overheating after I built a front reciever that blocked the holes on the frame. I mounted a cooler behind my skid plate and problem solved. Cooler lines shown in pic going into rad. Simple add to or bypass cooler to these lines.

James Dean

I thought the small cooler on the frame rail was for the transfer case?

mt_goat

It is, although there is some sharing of ATF between the two on the A340H.

To the OP, here is a good aftermarket cooler to use (http://www.importperformancetrans.com/coolers.shtml) because it will bypass the cooler when the ATF is too cold. I use the 4454 size, mounted behind my skid plate.

I would also add a trans temp gauge so you know where you are at (might start with that) The factory AT temp light doesn't come on until around 305* F and goes off after the ATF cools back down to around 250* F, if its working right.

Mounting locations and such have been covered many times on here so a quick search should bring many hits. Here's one of many: https://www.yotatech.com/forums/f2/b...cooler-126953/

slosurfer

Hey Dale, did you not end up going with your double coolers mounted between the ac condenser and the radiator?

mt_goat

No, I ended up removing both of them. I was needing to maximize air flow to the radiator so I removed one (two was really over-kill), then I moved the one remaining down to behind the skid plate and put a fan on it. My engine coolant temps were demanding max air flow to the radiator mainly due to the supercharger. Cooling the ATF is easy compared to that. My hottest fluid temps (not counting exhaust as a fluid) in order are, engine oil, engine coolant, then ATF.

Coyote Kid

Update: I picked up a high efficiency cooler from Auto zone, plumbed it in series to the radiator tranny cooler lines, had to zip strip it to the plastic grill as there was no place to put it in front of the rad. I went in to Toyota to have a total flush of the almost-black fluid, but again he talked me out of a full flush; I insisted he drop the pan to see if the screen was plugged; it wasn't but the crud in the bottom indicated the tranny was high mileage. I've had no problems since, and the tranny is working normally (at least for now); wish I would have put the cooler in right away. There was a reply that spoke of a bypass option on one cooler, but in my case I always have a 10 mile drive at 20- 30 before I get to a paved road and faster speeds. This cooler was about 1/2 the cost of the other one that would have had to be ordered.