2000chersport

I have a transmission temperature gauge on the hot line going from the transmission to the cooler. It has been getting up to 200-210 degrees lately. I've drained and filled the fluid 3 times in the past week and it still is getting to the 200's. So the fluid is good

The fluid does not go through the radiator. It's routed straight to the HD transmission cooler from o'reillys.

Is 200 degrees on the hot line (before the cooler) sound normal?

If not, I'm going to add a second cooler today

CompleteCherokee

180 degrees is typical operating temperature. Have you verified that the gauge is accurate (laser thermometer pointed at metal around the sensor)?

cruiser54

Generally the trans temp will equal the engine temp as they use the same radiator.......

2000chersport

The gauge is accurate. And the transmission has it's own cooler. It does not flow through the engine radiator because that's how I made it. The transmission lines only run to the aftermarket transmission cooler

2000chersport

I have 35's and 4.10's.

I just need to know if 200 degrees is normal for the hot line or if it's over heating at all

cruiser54

Lookie what I just Googled.

http://www.txchange.com/heatchrt.htm

2000chersport

Thankyou for that!

So basically anything above 250 degrees is terrible and if I'm hitting 200 then I just need to change the fluid more often

cruiser54

Factory recommended interval is a drain and fill every 30,000 miles.

Do it at 15,000 if that makes you feel better.

Do you live where it's cold in winter? If so, you're better off running the fluid through the radiator trans cooler/heater.

Use only Dex/Merc fluid.

2000chersport

Florida, that's why I didn't route it through the radiator

djb383

Have u thought about routing the tranny fluid thru the OE factory cooler 1st........then from there thru the aftermarket cooler? The factory cooler is in the "cool" end of the rad. My guess is the "cool" end of the radiator (where the factory cooler is located) would be say 20* cooler than the hot end of the rad. So, if the "cool" end of the rad was say 180 and then the tranny fluid went from the "cool" end of the rad to/thru the auxiliary cooler for a little additional cooling, u might be at the cool end of that chart.

FWIW, the instructions that came with our B&M tranny cooler said "for max cooling, mount the auxiliary cooler inline with and after the OE factory cooler".

I don't know about our XJ tranny temps because we don't have a gauge monitoring tranny fluid temp on it. We do have a auxiliary tranny cooler mounted inline with and after the OE factory cooler. I have the same B&M #70264 tranny cooler (that's on our XJ) mounted on our 2 others vehicles (RAV4 V6 and GMC Canyon V8). On those vehicles I can monitor tranny fluid temp with a ScanGauge II. What I have observed is, tranny fluid temp rises much slower than engine coolant temp and I've never seen tranny fluid temp equal to engine coolant temp.....tranny fluid temp is always 20-30* cooler than engine coolant temp.....at least that's what I observe on those 2 vehicles.

2000chersport

The deed is done

djb383

Wow! Hope that doesn't add extra heat to the condenser and rad. What tranny temps r u seeing now?

Turbo X_J

You realize that you are pre-heating the air passing through the radiator, right?
Edit: best of luck to you.

2000chersport

If it doesn't work out then I'll undo it

djb383

My guess is, one could count the number of members here on 1 hand (maybe 2) that have correctly installed a gauge (on the outlet/hot side) to measure/monitor tranny fluid temp. Some really valuable info could be provided to the forum members, such as fluid temps using OE stock cooler only, fluid temps after mounting a auxiliary cooler and fluid temps with a stand alone aftermarket cooler (this thread). Hint, hint.