undertow119

Question: Does transmission fluid flow into the trans cooler all the time, or only under certain conditions?

Why I'm asking: I was driving on the beach last weekend and my trans temp got as high as 250F (I have a temp gauge). When I shut it off and placed my hand on the trans cooler (I have installed an aux cooler in front of my radiator), it felt warm, but not hot. I would think with the fluid at 250F I wouldn't be able to put my hand on the cooler if fluid had been flowing through it.

So now I'm wondering if (a) fluid isn't getting to my cooler at all, or (b) maybe it only flows through the cooler when in certain gears (I was running at around 20mph in the sand, so probably in 2nd gear, 4hi). Normally on road my trans temp runs around 150-160. Just wondering why it got so hot this time, and why my trans cooler didn't feel hot.

Thanks for any insight.

blazer4949

I bought the trans cooler but have not yet installed it. Noticed that using the tapered barbs the inside diameter is less which would mean less fluid will flow. So....thinking that I might get a metal tube the same diameter as the hose so as not to decrease the flow and of course not use the barbs but still use the screw clamps.

RedneckJeep

The only time fluid does NOT flow is when the engine is not running.

hawgrider1200

u check for a crimped line?

RedneckJeep

Where do you have the temp sensor for the gauge?

TINMAN080

Crimped line= pump pressure blocked= no transmission operation. The barbed fittings will NOT restrict tranny fluid enough to have ANY effect on your tranny operation. If your tranny temp sensor is in the pan- yes you can have a tremendous temp difference from the pan to the cooler. Remember the tranny cooler is a heat exchanger, and it takes virtually NO time to dump the heat once it enters the cooler. Remember the cooler loses the heat along its length, not side to side. The second the hot oil hits the cooler every inch of the cooler is shedding heat- by the time the oil gets to the outlet tube bang the heat is GONE....Air down your tires a little and that tranny will develop MUCH less heat in the sand- 4 lo even on packed sand is much easier on your tranny as far as heat buildup. Remember rolling resistance= HEAT

RedneckJeep

I go along with the crimped line theory....AND the possibility of a line that's broken down on the inside. This is why I detest using rubber line unless I HAVE to. It can collapse in on itself on the insied layer and clog itself up. You'll never know it from the outside. You can't just go to the store and buy 3/8" fuel hose. It takes the good stuff to be impervious to transmission fluid. It take sure nuff hydraulic hose. Just like power steering hose. Same stuff. Unless you have that, you got the wrong stuff. It's usually around 3-5 bucks a foot. That's why I always recommend hard lining an auxilliary cooler in.

tgrt

Good answer!

TINMAN080

AWW SHUCKS

ronjenx

Let's repeat the question:

Where do you have the temp sensor for the gauge?