I have read in posts that factory tran-temp guages aren't dependable,but have nofirst hand experience

 

You can trust the stock gauge to stay right in the middle until the trans gets to 230F. Then it will move to the yellow. At 250F it will move to the red.

 

yeah they wait till your trans is in trouble before they tell ya about it... and i would never trust a gauge that NEVER moves anyway... my trans temp gauge always slowly moves up till it hits a little below 180 then it stops... unless i'm doing something like a high-quality boosted launch lol

 

I would say that you could use overdrive until one of two things happens: either the transmission starts changing gears frequently or the clutch fan starts engaging frequently. Both are pretty good indications that the truck is really working to maintain speed and dropping out of overdrive can more than likely help it out.

 

you trans wil stay in lock up as long as your stay over 65 mph. i would install a large trans cooler. the key word is LARGE cooler. and put it on the return line going back into the transmission. slush boxes like cold.

 

Whether or not to use OD when towing is nothing more than common sense (of course, it seems that's pretty hard to come by these days).

Towing 7,000 lb is a whole bunch different than towing 15,000 lb. The original post was for a relatively light load.

If you're towing a big load, keep an eye on the boost gauge or the EGT.... if you're running a lot higher than usual, take it down a notch. If you have an automatic and it's hunting, or if the temp is too high, take it down.

 

I recently had to replace my tranny due to catasophic failure in the stock unit. My stock tranny temp gauge never moved. My Autometer gauge was reading sky high.

The stock tranny temp gauge is,"as useful as a poopy flavored lolly pop."

 

Edit: oops! I already said that.

 

................NO you can't,it's an idiot gauge,will not move tell it's toooo late,I have a programer in my 2002 with piller gauge's and the factory gauge like your's never move's past 3/4's on the little icon and reache's that point in a couple mile's from a cold start,the piller gauge take's several mile's to get to 100 degrees,while towing the factory gauge stay's right at that 3/4 mark even when the piller gauge get's to 180 degree's which is as hot as it ever get's,truck and 5'th wheel weigh's 20,900#'s at the scale,keep in mind the guy with the 2000 psd has the SMALL factory tran's cooer,2001 and up has a larger tran's cooler,1999&2000 model's tend to have heat problem's while towing if they have not had a larger aftermarket cooler instaled ,more so when backing an RV/or any trailor up hill they heat up FAST,if one has 4 wheel drive using 4 low while backing will be better for the tran's!!!!.

 

...............I forgot to add that I tow in OD all the time weighing 20,900 #'s total at the scale and have never had an issue,I lock OD out when climing MTN'S,small hill's no problem,my programer bump's the line pressure in the tran's also.