4R100 Acceptable Operating Temp Range

[Byrnedw]

Hi, I have a 99 F250 4x4, 7.3, Ford Reman 4R100 with 65,000 mi, aftermarket cooler, 3.73 gear ratio, Mercon V. Would stable low 180 deg temps be an acceptable figure running an empty truck on the highway on an 85 deg day? This trans starts leaking fluid from the inspection cover at about 180 deg and I am trying to decide if I just replace the seal or if there might be some other problems internally. Seems to shift and operate well and I can't feel any slippage. Temps were read with SnapOn scanner through the OBD hookup.

[HVAC SuperTech]

that sounds about right. may be the seal. You could check to see if the bypass tube is blocked.

[HVAC SuperTech]

oops...
I think this is how you do it.....
to check the bypass tube, get the trans to running temp(over 100*) and take the rear peice of the tube loose. if you get fluid out the back port, its bad. Dieselsite.com has the way to check the trans. look under the trans bypass tube, it has directions.

[Byrnedw]

Thank You. Yes, I did check the bypass tube, it pumped 2qt in 10 seconds through the cooler and none came out the return line so I don't think it is blocked. I'm trying to judge how good this trans is as it is expensive to pull it to due to a 10.00 seal. I've noticed in some other threads guys talking about 150-160 deg and wonder if low 180 was high side of acceptable- at least it seems to stabilize there.

[lcducote]

180 is still ok.. you dont really want to see more than 200 IMO.. as far as your leak goes its either the torque converter or the input seal for sure. also shouldnt your trans be under warranty or are you up?

[FordNutz]

You can run 200 all day long with no probs but, if you normally don't run that hot and somethig is different, like a hot day or your towing heavy, then you might have an issue. The factory pump seal is a POS find the viton seal if you can.

[Byrnedw]

Appreciate the feedback guys. I'm going to try a new Viton seal and a 6.0 cooler and see how long it will last. Thanks Again

[HVAC SuperTech]

Where are the pumps in the trannies? if one were to go bad, do you have to take the complete thing out to change it?

[jkkeough]

chime in if you think of something here. temp w/o load 150-160 deg temp with load has gotten as high as 194. load is a 16x7 enclosed trailer or 8K tractor. when around town or on the hilly back roads i like to run w/o o/d due to the chug effect. my dash gage dosent reflect change in temp and my bullydog programer has a didgital display so that is where i an retrieving my data. my next step will be to get a IR therm gun to check for hot spots. DOES ANYONE KNOW WHAT FORDS SPECIFICATION ARE FOR A STOCK 4R100 TRANS TEMP RANGE AND GAGE RELATIONSHIP?????

[Dietoremain]

my trans with a trucool inline with the stock cooler barely hits 145 when its 80's out.. stop n go maybe 155, just saying..