I just installed a B&M 24k Tranny cooler and a Autometer temp. gauge on my 99 Z28. I still have the stock stall for now, just doing these in preparation for a Yank SS3600. The fluid is run through the radiator then the B&M cooler. The sending unit is installed in the pressure port.
Anyway I took it out for a 15-20 minute test drive. It is about 40* here. After a few burnouts, a few WOT runs through 1st and 2nd gears, and brake stalling it a couple of times, the temp. on the gauge never got over 125*.
I assume this has to be a bad gauge or a bad sending unit. Does anyone know what the output voltage should be from the sending unit?
Thanks,
Kris

 

not sure about the output reading but you should be able to find that info on the manufacturer's website. fourty degrees is pretty cool and with that kind of weather here i wouldn't be surprised if i could barely get mine to 125. sometimes it takes me ten minutes of driving around on cold days for mine to even register the lowest temp which is like 70. i have mine in the pan btw.

 

Thanks man, I wasn't sure if 125* was normal for colder weather or not. Everything I have read has mentioned temps from 170-200+ degrees.

 

most likely those reading were taken in summer which you will probably see those temps. winter time will take a lot longer for a stock trans/stall to reach anything above what your seeing now.

 

+1 i agree

 

mine will see 180-190 max in the summer so yeah i agree too

 

I have two 24K B&Ms routed like yours and this time of year only get about where you are temperature-wise. I'll tell you that my worktruck, with its OEM cooler, hardly gets above 150*, even when it's warm outside, and that' with a tiny cooler less than half the size of the B&Ms I have.

I think you're okay.

 

I really appreciate it guys, I can't complain about it running that cool. Now I just need to get the stall in there.

 

i thought mine was broken too cause it took forever to warm up. even then its never been over 170 degrees. bm 24k cooler and summit deep trans pan

 

As long as you did not use any "thread tape" on the sensor, you are getting an acurate reading. I have a stall, 24K cooler, and 3 qt deeper pan, I was out in 57F weather, and my trans temp never went above 140F.

SteveC

 

the reading may also be because its in the pressure port and not directly in the pan.. my trans builder told me the only way to get a true reading was to have the sensor installed in the trans pan itself not in the case or in-line with the cooler. Just my .02

 

I have my tran temp sender mounted in the pressure port too and i have an aeroforce guage that will read the trans temp from the pan. The guage in the pressure port reads much slower. If I beat on the car and get the temps up the regular guage will be like 5 to 15 degrees cooler. it will eventually catch up after like 5 min. Same goes the other way, if i turn on the fan on my trans cooler the aeroforce will drop much faster than the regualer guage. But while cruising the guages will read the same.

 

I may move the sender to the pan then, to get a more accurate reading. I have a drain plug kit that the sender will thread into. I may install it on the side of the pan at the very bottom, then I can just unscrew the sender to drain the pan. Is this a good idea? Has any one had any problems with the drain plug kits leaking just using the plastic washer they come with?

 

im about to install a trans temp gauge in the pressure port, will unscrewing the pressure port screw do anything? like decrease the line pressure?

 

i put a drain plug on my old transmission. i could not get that thing to stop leaking no matter what i did. the fluid always found its way down the threads and dripped. that plastic washer is crap. mine broke in half the second i started tightening it down.

 

The oil in the pressure port is dead headed so to speak and will have a slight delay in showing actual temperature. Ideally you want to know what the oil temperature is in the pan. This is because after flowing through your heat exchangers the oil lubricates the center of the gearbox and then goes into the sump. The critical temperatures is what is at the filter inlet.

 

how long is the sender unit suppose to be? i bought a sunpro st trans temp gauge and the sender is about an inch longer than the bolt in the pressure port, and wont go all the way in to where i can thread it. its like 2.5 inches long compared to the stock bolt being like an inch long

 

I really do not like the sender in the pressure port. I have seen the sensor get damaged when it bottomed out in the case. I have also seen the case crack on a few occasions. My opinion is to install it in the oil pan or in the return cooler line.

 

I just orderd the Autometer weld in bung for 1/8 senders and welded that into the side of the pan and when i wanted to drain the trans i just took the sensor out so it works like a drain plug and it sealed perfect never a drop of trans fuild came out

 

That sounds like a good idea, I may order one of them.

Also, on my way home tonight, I run the car kinda hard through a long, curvy road and the trans temp got up to about 155*. So apparently the gauge is working properly. During normal driving it never gets over 125*, can't complain about that.