davelinde

I picked up a second temp gauge to check the stock temp sender (I'm seeing some pretty high temps). I bought a DiPricol gauge and sender together and installed the sender using a clamp-on to the hot line (I know that will read cooler but I wanted to do this quick).

Well... the gauge registers nothing. The backlight works (dimmed/switches with my headlights) but when I turn the gauge on the needle quivers a little and then just sits at 100 no matter how hot the tranny gets. I thought maybe I reversed the polarity so I just double checked that and it's OK - I get 12V at the splice to the connector. I re-seated the connector in the gauge and checked the connection on the sender...

One thing that seems odd is that labels on the back of the gauge do not match the instruction sheet in the gauge - I followed the color coding/connector positions on the instructions. Not sure what else to check, I'd think something like this would work out of the box. Any idea what voltage I should see off the sender? Maybe I'll check that next...

zuki_dan

I bought a full sweep trans temp gauge from diesel manor and also bought the wire harness and the 2 outside wires on each side of the plug were in the wrong order so I pulled it apart and straightened the wires out the same way the pigtail on the gauge was wired and mine has worked fine ever since.

Howling

Run a separate ground from frame to the clamp-on (hose clamp works well) temp sender.

It will work then.

davelinde

THANKS! Will try it - I had wondered how that sender would work with no ground reference...

davelinde

That did it, working fine now! I ended up clamping a ground wire directly to the sender body with a second small hose clamp. The clamp-on thing was coated and there was no continuity between the clamp and the sender.

Now I'm wondering if I actually chose the hot line... I measured them both with my IR thermometer and what I thought was "hot" was few degrees cooler than what I thought was "cold".

However... all three measurements - my X-monitor, the DiPricol, and the IR thermo are all within a few degrees of each other at low temps. So I guess this will bring me back to the million dollar question of "how hot is too hot" for ATF+4 in a 48RE under full loads.

no_6_oh_no

Your temps will vary depending on TC lockup, speed, load, ambient temp, etc. Empty, in lockup with triple digit temps I am running 170-180. In fluid coupling stop and go traffic it will easily jump to 220 degrees.

Under a load slow driving will push things way up over 260 unless I use manual second to get lockup. In lockup I will generally see 190 or a little more more depending on the load.

The temps all fall drastically as the ambient temp goes down.

ATF+4 is rated to handle temps of 320 degrees without breaking down. Anything under that is acceptable for short periods. Changing fluid more often is a good idea if you are constantly pushing the limits.


How do your temps and situations match mine?

davelinde

When I was towing 12' 6" and 10,000# I would see temps like yours - mostly climbing up in stop/go traffic and running much cooler at highway speed with TC locked. Now that I'm towing 13' 6" and 13,000+# I see the same temps in stop/go but also if I tow faster than 55 mph I get a temp climbing up to 225-235 or more until I back off the speed. Sometimes I can run 58-60mph for a while with the temps at 220ish but then they will just spike. The engine (of course) can pull as fast as I like to go and the tranny is not slipping obviously - it's holding RPM's fine.

I now think my new gauge is on the cool line and interestingly it stays right at 140 even when the factory gauge hits 200. Tomorrow I'm towing 400 miles and will leave the second gauge on the cool line to see what it does. Sunday I'm towing a few hundred more miles and may switch the sender to the other line for more info.

no_6_oh_no

The temps are not out of sight but are a little high. Couple of thoughts, do you have a stock trans? No shift kit or other upgrades?

Thru having to rebuild my trans, I have found that a stock trans will generate a bit more heat than is comfortable when you push the weight or resistance by slipping the directs and TC clutch. A shift kit and TC solved that problem but a shift kit helped by itself.

The other issues that I have seen cause temp spikes is the drain back check valve. In lockup you have full line pressure running thru the cooler. The check valve is evidently restricting flow enough that the trans won't cool correctly and temps spike. Removing the ball from the check valve has solved the spike problem in 2 cases I know of and adding a secondary cooler has brought the temps back down to very reasonable under a load.

Some things to consider that are relatively reasonable cost and easy to do. Good luck.

davelinde

I have not done any tranny mods yet... still a bit ignorant on what they are and how they work. Exactly what is a shift kit?
I'd already found the thread on drilling out the check valve and removing the spring and flow restricter... that does seem like a good thing to consider. In fact a local tranny shop suggested that too and said they do it on all their stock rebuilds.

I'll probably post all my findings in a separate thread on tranny temps for input... but in short form I found that my cool line runs exactly like I've seen others report for their pans - goes up to about 140 then runs between 140 and 160 no matter what - even if the X-monitor was showing 250.

My X-mon is running from an internal probe and when I switched the second gauge to the hot line the difference there was interesting. The two temps tracked exactly up to about 180 or so and then the X-monitor went up to about 210 (with peaks to 240) while the hot line moved between 160 and 180.

However twice the hot line peaked while the X-monitor didn't move off 210... Once from a dead stop on a steep hill I pulled hard for about 20 seconds and the hot line immediately went from 160 to 200 (then back to 160). Later backing up on gravel I was fighting the triple axle for about 2 minutes and the hot line went to 220.

Still not sure exactly what to conclude except that the probe location can make up to an 80 degree difference in temp reading and now that I've got data from three locations my temp readings no longer sound so high (compared to others here).

no_6_oh_no

There will be a difference between the return line from the cooler and where the X-Monitor is reading of the stock sensor in the pan. The cooler return flow is routed to all the lubes points in the trans before it falls into the pan. You pick up heat from the trans working between the 2 locations. Depending on how hard the trans is working that difference can run up to 100 degrees.

What type of sensor are you using to read the hot line? Those temps should be reversed with the pan temps staying between 160-180 and hot line temps jumping up over 200 if you were running in an unlocked TC condition. Your hot line output should almost always be greater than the pan temps due to the compression in the pump and fluid coupling. Check that hot line sensor again as it sounds like it may not be reading correctly.

A shift kit goes in the VB and essentially raises your line pressures and to a certain point modifies the shift to the better. Higher line apply pressures are going to stop slippage in the gears and the TC. Also, when the TC is locked you are running line pressure thru the cooler. This is going to circulate fluid faster to help cool it better. Getting rid of the check ball will enhance circulation quite a bit. Downside is it will eventually cause warpage on the stock converter that will lead to the clutch giving up, and possibly loosen the flex plate to TC bolts and cause flex plate failure. I ran 10k with a stock converter and a shift kit and when pulled the TC the bolts were starting to loosen a lot more than I like and you could see marks on the convert lugs where it was starting to walk flex plate around. A billet cover TC will help this a lot as you have almost 100 percent of the flex plate sitting tight against the TC cover.

You have an 04 with the TV cable still there so you can set up the pressure to delay shifts until the line pressure is up. I would fix that check ball, put a shift kit in, add a billet band strut and the front accumulator cover while it is apart, and get the TV pressure as high as possible and still make driveable. That will fix everything but the TC and should make a difference in how it works. Once the shift kit is in you could add a plate cooler with a thermo activated pan if your cool line temps won't come down. If you have fluid returning at 140 and are still spiking temps at the pan and hot line all the coolers in the world won't help. It is a slippage issue somewhere else.

davelinde

I've got a DiPricol sensor on a clamp-on fitting - the sensor came with the gauge. The clamp-on fitting is advertised to be within 5 degrees of the fluid temp and it does seem to be accurate?

The stock sensor and hot-line track exactly up to about 160 degrees or so. After that the two read quite differently.

How does the fluid flow? I had assumed that the return line went into the pan, then the filter pickup in the pan pulled into the tranny to all locations, then the return came out hot and went to the cooler, and from the cooler to the return and back to the pan??

For sure, my temp data does not support my assumptions.

For clarity and more participation I'm going to post my tranny questions under a proper title.

no_6_oh_no

I am going to post my thoughts on your other thread.