WHOA MAMA, Trans temp!
 

So I finally got my trans temp gauge all setup correctly with it's own
ground since it wasn't grounding properly through the cooler line.
And to my chagrin [verymad] it shows while I'm driving under 30 in the
city that my trans temp is on the line between 180 and 210.. which I would
assume is like 195.. :o ..... That's no good isn't it? Seems super high for cruising not underload. If I hop on the freeway it drops down quite a bit to just under 180. But come on now, the ambient temp here right now is like 55.
I checked the trans fuild level on a level surface in neutral and it came out
RIGHT on the top of the crosshatches. However there were some bubbles on the dipstick. I use valvoline ATF+4...


What gives??????
Too much fluid??
Seal around the trans filter bad??
Bad fluid???

ARG!!

i have the same issue...and it gets me worried about ill effects the temps will have on the trans

Check you cooler fins to be sure they are clear of debris, then get a torque converter lock up switch. That will lower the temps when just around town. The torque converter builds most of the heat in a transmission when not locked up.

Remember when running around town the converter is not locking up much and heat will climb. Also remember ATF is going through radiator for reheat.You are reading cooler line temp and that will be even higher.
At higher speeds you will be in Lock up and heat will be minimal.
The numbers sound about normal and compare favorable with mine. I read the numbers with a DRB111.
ATF+4 is good to at least 250 degrees.When it starts changing color toward brown it is time to change.

Whew.. and I was all scared. I thought the trans wasn't supposed to get over like 180 without sustaining serious damage. That's a relief.

I think I'm gonna go for the lockup switch. However I'm a little concerned about hurting my stock tranny.. I'd like to mount the switch to my shifter, anyone know of a prefabbed switch that will hook on that puppy?

3rd Gen tranny cooler is a seperate unit. It does run through a preheater on the motor before going to the cooler but it does not run through the radiator. If you are stuck in traffic without the TC locked up you will create some heat with the factory TC. Get worried when you hit 230 deg. Backing up a good distance will def. get the tranny hot...

ATF +4 is a group 3 synthetic, good for short durations of 320 degrees. Your not even close to a dangerous temp.

Unless your towing heavy in slow traffic, you don't need to do anything. In automatic mode you will not get lockup in 1st and 2nd and the temps will climb up a bit but that is due to the sloppy converter. Not a big deal.

Lockup switch won't help unless you modify other parts also. You still won't get lockup in 1st and as soon as it hits 2nd it will just stack shift into OD.

If you want or need better performance, a good TC and VB will be all you really need to keep things in check.

Mine is usually inbetween 125* and 150*, the hottest I've seen it was 180* with the stock pan while towing through the hills of Utah...anything above that without a load would make me nervous too.


I use MOPAR ATF+4 and my pickup is in bung on the Mag-hytec DD pan but the temp's are the same now as they were with the factory pan.

Same for me.

The temps the OP reported were about the same as what my previous Duramax used to run. I wouldn't worry too much about it but it does seem hot for a 48RE.

unless you see boiling point... you temps are fine. A built trans will runs much hotter than a stock because of the higher pressures. It probably doesn't benefit the trans to see trans real high for a long time but, the stock cooler is pretty efficient. 180F is nothing.

Yea, it surprised me too when I saw the temp gauge rise to 195* sitting in the drive thru on a 30* day. I talked to a couple of mechanics I know and they said it was normal for today's transmisions and the new fluids. When I'm on the highway, it is fine. Can't wait to see how high it goes when I'm towing my 9,000# camper this summer when it's 105* outside.....[coffee]

tiara3100- i see the same temps on my gauge, in the same outside temps as you. i have one gauge in the hot line and the other tranny temp gauge in the pan- there is 30 -40 degree difference in temps between my two gauges

My sender is located in the hot line also. Amazing how hot that 48RE runs.... Before I installed the sender, I can only imagine how hot that tranny got when I was towing my camper with the TC unlocked in traffic in the summer :o

Being its winter time anyone with a winter front, or um eh, cardboard infront of the radiator is also blocking airflow to the tranny cooler, its going to be warmer than normal if thats the case.

my tranny temps usually hit around 130 on my 40 minute commute to work. i noticed it gets up around 160-170 in stop and go traffic... now when i get my built tranny installed i expect the temps to get alittle higher. im not too worried about them.