mcoleman

I always use my mystery/lock-up switch when towing the hay or horses here in the Ozarks. It holds the truck back a little and the EGTs drop to 200 degrees or a little lower in some cases. I've never seen my tranny get over 160 degrees according to the gauge.

GSP

I think she is worried about the Auto trans fluid temp , not the EGT.

My trans stays cool always in lock up pullin mountains in the west with my 5er, Only time it gets to up around 180 degrees is out of lock up.

I have a trans temp guage before the oil goes to the trans coolers .

Most time my trans temp is only 140 -150 in lock up.

Best thing to do is get a trans temp guage so you can see whats happening. Above 200 degrees on your trans fluid is when you need to pay attention

phox_mulder

8% grade, 6 miles uphill, very curvy road, 25-30mph speed limit.
Tranny temp guage climbs very fast past 250, past 270, uhoh, sitting at 280(pegged) for the last 2 miles.
As soon as I crested the hill and could get the speed up past 40 and achieve TC lockup it cooled right down to 130-140 in no time.

Stock truck fuelling wise, pulling a 4wheeler trailer loaded with 4 days of camping supplies.


phox

GSP

OOHHEE 270-280 . I bet you dumped that oil soon as you could and put fresh in.

Pulling a grade out of lock-up, she sure builds up heat fast . then cools right down back in lock up. I like my trans temp guage!!

That long grade north out of bishop toward mamoth is a doozy.

Then there is that big bad hill in Idaho going north past white bird.

RATTLINRAM

That's where an upgraded TC/VB and "Mystery Switch" comes in handy. With the way my 47RE is set up, I could pull that same grade and never get over 150-180. My set-up allows me to lock the TC in any gear at any speed.
There is another thread HERE that Papa Smurf started and pertains to his wifes 2004 48RE. He was noticing that when taking off in DRIVE from a standing start, his tranny temp was climbing rapidly when the truck shifted to to 2nd and would stay unlocked till it got enough speed to change to 3rd unlocked and finally 3rd lock-up before the temp would stop climbing. Apparently the 48RE will lock up in 2nd gear if the shifter is placed in 2nd.
Once again, a trans temp gauge with the sending unit mounted in the hot line coming out of the trans will let you see exactly what is going on inside. It is amazing to see how the trans will cool as soon as you lock up that converter.

fortunate1

Another vote for the TCC lockup mystery switch. That will keep the tranny in top gear, and give a little engine braking. OD lockup at highway speeds will give the lowest tranny fluid temps. Don't know if a mystery switch can be used in a 3G ram; it was a very simple install in the old 47rh.

JyRO

Yun's mystery switch will also yield yee maximum mpg, right? Better than if yee mystery switch ain't activated, is what I reckon I'm gittin' at. I'm not a slush box lover, but if I had one, I'd have to get all those fun switches and stuff.

adkl1

my 48re sits around 190-210 in town. but when im hooked up to my 33' toy hauler around 16k it also will stay around those temps on hills or flats. the outside temps around 105+.

GSP

Rattlinram , You said if the shifter is placed in second the TC will stayed locked in 2nd?

That would be nice . Can that be verified?

I know commin down the local steep wineding mountain I put mine in second so I dont pick up speed and have to ride my brakes all the time. I dont think its locked up though.

signature600

With an aftermarket VB, it will lock in 2nd. Even lock in 1st if you get it setup that way

Chris

JKM

Wrong , for a P pump at least , if your in gear , coasting down a hill , it injects absolultly NO fuel at all. The with your foot not on the pedal , the govoner is pulling the fuel away to bring the engine back to an idle state, but with gravity pulling the truck down the hill , the engine keeps turning , all the while the govoner is holding the fuel off , until engine rpms drop low enough that the govoner starts to pull back into fuel to idle the engine.

JyRO

JKM, I believe this. Its what I tried to describe a few replies back. The way my truck (VP) acts and sounds when it is coasting downhill, it honestly feels and sounds like it is getting no fuel.