This has always puzzled me. I have a 2002 F350 S/C 4x4 7.3 A/T XLT with 31000 miles on the clock. Truck runs great, and I had the 30000 maintance completed when needed. I have always noticed that when I drive the truck, the factory transmission temp gauge reaches the half way point or less, no problems there. When I shut the truck down, the gauge goes to the cold position. When I turn the key to the Wait to Start mode, the gauge returns to a operating tempature but not the cold position. I asked the service advisor at Ford about this, and he stated it was normal. He advised the transmission tempatures in a diesel get very hot, and the transmission tempatures stay very hot for a period of time, which causes the gauge to register this way.
My question is, is this normal, and if so, will the transmission tempatures return to a colder reading as the weather gets colder?

Thanks in advance for your feedback.

 

I have the same truck, and yes that is very normal. The tranny gauge is not very accurate on these trucks. Someone posted a link not too long ago where someone tested the accuracy and approximately what temp you were running according to the needle position. Good read, but I couldnt find it. I'm sure someone else has the link.

Summer time your gauge really won't move much. Winter time morning starts and you'll see the gauge all the way down. Don't worry, it will quickly warm up much faster than your engine.

 

Blue monster,

Haven't seen you in a while hope all is well. Yes this is normal for your tranny gauge to be....well worthless. This is one of the reasons when you buy after market gauges you should get the tranny one too. The stock gauge is more of an idiot light with a needle on it. If you are towing anything I would suggest a tru-cool max tranny cooler and get the gauges too.

Fire Rooster

 

that is normal for the guage to do that. i have an 03 model and it does the same thing.
you aint got anything to worry about.

 

Blue monster,

If you use your truck for any towing or heavy loads, or are going to do any mods to the truck. Get the gauges and get all three, the pyrometer, boost, and tranny. If these applications do not apply to you. then your stock gauge is just fine. The big reason you want the tranny gauge is it gives you a real time number value for your temps. the optimal running temp of your tranny is 135-180 degrees. Obviously the cooler the better. The stock gauge does not give you a number value so for towing etc. it is a good idea to get aftermarket stuff, so not to burn up the tranny.

Fire Rooster

 

The stock gauge is designed to go to the middle of the operating range and stay there from about 51*F to 230*F.

The upper part of the range is about 230*-240*. About 240*-250* it will hit yellow. It will go into the red at about 250*.

Normal operating range for the tranny is up to 230*, although under most conditions, most people see 170*-200*. The design specs for the 4R100 and the MERCON fluid allow for sustained temps up to 230* with brief (<30-45 minutes) spikes up to 248*.

Cooler is not necessarily better. Yes, 180* is better than 250*, but 180* is not better than 190* or 200* or even 210*.

I pulled 7000 lbs. in 90* heat through rolling hills (tranny downshifted into 3rd 3-4 times). My gauge went to the middle of the "normal" range within a few minutes of heading out in the morning and never budged the rest of the trip. I never gave it a second thought.

 

Thanks to all for the feedback. Good to hear from you Fire Rooster, doing well and hope you are too. I feel a little better now knowing this problem is not a defect with my truck. I do plan on upgrading with reliable gauges soon, although I really don't plan on any heavy towing. I may fill the bed with firewood soon for winter stove burning. Much as I like my truck, you would figure Ford and others would supply their trucks with better gauges. Heck, most of us would pay the added price on the sticker as long as it was with in reason.