Ok I've searched but can't find anything...

1. What's the rear differential temperature suppose to be, normally and while towing? (180 sounds right, but i see 250 on the highway not towing. should be colder with the MH pan IMO)

2. I've added the Mag-hytec cover with a sender in the top for the gauge. But the sender will not see or touch the fluid/oil until I'm moving. Why did they place the port on the top?? When I get in the truck the gauge reads 125 degrees and it's been sitting all night, it must have something to do with no resistance because the oil's not touching the sender. What do you guys think...

Thanks

 

I ran a gauge on my Mag Hytec for 2 yrs. Never saw anything close to 250*. At gross Wt. and on a 100* day at 75 mph, I might see 220*. Hwy, empty was around 180*.

The Mag Hytec temp probe works off the squirt & splash method. Takes a while to read much activity, but is accurate. Reason for it's location, I have always assumed, is to reduce chance of leaks from a probe submerged in the gear lube bath?

My gauge read from 100* to 280*, so I showed no activity unless on the Hwy for about 10 min. These readings were with a high grade Synthetic.

I question the accuracy of your temp probe, if reading that high on first start up. Easily checked...just dip it in some boiling water.

RJ

 

I know it works because i have a double throw switch to read between the trans pan and diff pan. In the Trans position it reads a touch below 100 until it heats up. (autometer trans temp 100 to 250). I added a ground wire from the pan to frame in case there was a ground issue, but nothing changed.

 

I think he was referring to the fact that you have two probes in your truck - on in the trans pan and one in the diff pan (unless you switch them rapidly) - and that the one in the diff pan may not be working correctly.

Why don't you invest in an IR thermometer, and take the truck for a fast run down the highway. When it gets up to 250F, pull over onto the side of the road and shoot the diff temp on the pan. At least you'll know if it is indeed 250.

Personally, if it isn't making any noises/whining, I'd drive the heck out of it and wouldn't worry about it.

 

The sender on both pans is brand new, really just a brass probe, which I'm sure you know, weird. I have an IR Temp gun, good idea, I'll try that.

 

I am not familiar with the Autometer gauges, but it might be that the gauge readouts for transmission sensors are scaled differently from differential sensors.

 

I'm pretty sure temp is temp but the thermo gun will tell all. My guess is a bad sender or your fluid level is low but I'm sure that's already been checked.

Good luck.

 

Would any one think that the wire going to the diff is still picking up some of the heat coming from the trans pan?

 

It should only read the temp at the sensor. Something is bad if it reads 125 after setting all night. They put the sensor where the lube is the hottest - the spray from the ringgear. I just put TCs on mine and plug them into my Fluke 52. I haven't driven much yet to tell - local driving ~170 diff and ~160 trans. Craig

 

I won't disagree but my pyro reads ~275* when shut off always, never below. Now with the key on it will drop to ~200* after sitting overnight but never to actual room temps. Could this be the same thing happening? I do believe my pyro temps from others on the board with similar mods and gauges. I'm thinking it's designed that way but I didn't sleep in a holiday in express last night

 

Might pull the filler hole dipstick and read oil temp on it .... for a more accurate reading with the heat gun? Not sure how much different the aluminum case would read but suspect much lower than oil off ring gear.

RJ

 

OK,

-I ran a new wire from the sender to the gauge, nothing changed still 125.

-I pulled the sender and kept the wire attached and dropped in a coffee mug with 150 degree water. nothing but good because it read 0 (or 100). but then dropped a ground wire from the frame in the cup and it read 150 degrees. So the sender works.

I'll now go for drive and use my IR...

 

IR read 120, on the pan and inside through the dip stick hole and on the dip stick, but the gauge read 180. What gives when i switch to trans no problem read about the same as the other trans gauge i have on the hot side.

 

Can you swap the temp probes. My Tranny and Differential are identical (Tranny is in the hot line).
That should tell you something.... if you can?

I had forgotten, but I had a differential sensor (probe) go bad on me.... all ISSPRO gauges. Caused the needle on my gauge to jump way up...almost 280*. Sometimes it stayed there.

At least you know you don't have an overheating Diff problem!

RJ

 

Just noticed this comment. Your saying a tranny pan sensor reads the same as your hot line? Doesn't sound right to me?

RJ