Auto Tranny ideal temp range??

[bitman]

I need some guidance.

I just installed a temp gauge for my auto tranny fluid. Temp sender is in a "T" on the "out" line, just before it hits the radiator.

I know "heat kills" auto trannys. I've already installed a deep tranny pan, so there is more fluid than stock.

So -- how hot is _too hot_ before I should install an additional tranny cooler (in addition to the one that comes stock with the Jeep). The answer probably is "it depends" ... I guess what I'm looking for is "if you are running temps consistently of XXX degrees Farenheit or more, you probably need another cooler".

2002 TJ, 3 speed automatic.

Thanks in advance for any tech you can throw my way ....

Dave

[bitman]

My guess is that there are probably at least an even dozen regular posters who have _some_ idea how to answer this question .... you know ... you JV and Arizona/New Mexico guys!

Help me out here .... pretty please??

Dave

[Allen]

I wanna know the same thing.

In cool weather my temps are right below 100*F.

But in the heat and heavy traffic, I can see 180*F easily.

Allen

[Robert J. Yates]

If you hit 250-275 then you have problems as that's about the time ATF starts to break down.

200 on long uphills is not uncommon in TJ's and sometimes I see 220 on my tow rig. I run auxillary coolers in both. Pay attention, stay on top of your fluid replacement and filter replacements and you will be fine although I would go get an auxillary cooler.

BTW, some of us do get busy. Your question would have eventually been answered without having to complain about a lack of attention

[bitman]

Thanks for the response ... that is helpful. I know there is a lot of practical experience on this board with autos and hot weather -- those conditions aren't exactly what I'm experiencing right now, but it is good to know when to bite the bullet and spend a couple of hours installing another cooler.

I did say "pretty please" ...

Dave

[Brad]

Here's an article on the subject.

http://ca.autos.yahoo.com/maintain/a...smission1.html

Brad

[bitman]

That is an awesome link, thank you very much.

I think my cut point is going to be 180 degrees F (consistent temps), after reading the article. As I'm headed back to the DC area this summer ... I'll probably be installing one in July.

Dave

[Allen]

Originally posted by Robert J. Yates
BTW, some of us do get busy. Your question would have eventually been answered without having to complain about a lack of attention

C'mon Robert.

This is a top priority.

After all, he had to know right now so he can install his cooler once he's back in the States.....sometime in July.



Just kidding bitman.

I wanted the same info.

Maybe we'll run into one another once your back. Maybe do a little fishin' or wheelin'.

Allen

[bitman]

Well ... I've learned that there are only a few boards on the 'net that I rely on for accurate, to-the-point, sound knowledge and advice. This is one of them.

I lurk a lot more than I post. And I really am grateful for the help when I get it.

Dave

[Allen]

Originally posted by bitman
Well ... I've learned that there are only a few boards on the 'net that I rely on for accurate, to-the-point, sound knowledge and advice. This is one of them.

I lurk a lot more than I post. And I really am grateful for the help when I get it.

Dave

Well start posting some more.

And like I said, i was just giving you a hard time.

Maybe we can install our tranny coolers together when you get back.

Allen

[StealthTJ]

As others have already mentioned, 210~220 or so is about as hot as you'ld really like to see, and then not too often.
Check the fluid often and when it starts to darken in the least, change it.
Out here, in the hot west, I'd recommend at least every 10,000 ~ 12,000 miles, maybe more often if it's (the tranny fluid) been getting hot.
BTW, the ideal setup is two temperature gauges, one on the output and one on the input side. Not many do that (even myself).
If you're only running one temperture gauge, that I'd recommend it on the input line, not the output line.
There is nothing that you can do regarding the output temps, but if the input temps are high that there is something that you can (and SHOULD) do, and that is install aux cooling, as the input temps indicate how effecient (or not) your cooling system is working.
Set up like this, and keeping an eye on the ATF condition, you'll be good to go.
The problem with the gauge on the outline is that you have no clue how well the cooling is working.
If it's going out at 220 and coming in at 210 or 200 or even 195, then that's not good.
However if it's coming out a 220 and going in at 160, then that's fine.
Remember that the output line is taking fluid out, basically as soon as it leaves the torque converter, which is the max. temp. that it's going to reach.



Fred

[bitman]

Fred,

Thanks for the response.

I like the idea of two gauges, or at least two senders, and one gauge (with a switch). It would be easy enough to plumb and wire in, and I understand your logic completely. Doesn't do you much good to know your transmission fluid is hot unless you know the efficiency of your cooling system ....

Dave

[Robert J. Yates]

Just for perspective - my Suburban unloaded and running up the Cajon Pass @ 75 will show about 175 on the tranny guage. I put the Jeep on the trailer behind it and by the time I reach the top - I am doing 45-50 and the guage will be in the 210-220 range. The Cajon is a pretty good test as its long and steep.

I do full fluid replacements on the Suburban and the Jeep every 10k. Both have deep pan conversions, aux. coolers and in the Burb, I also added a remote filter when I did the guage. Both trannys run like they are new although the TH400 in the Burb has more than a few miles on it

[DanB98TJ]

Originally posted by bitman
I like the idea of <snip> two senders, and one gauge (with a switch).

A switch isn't necessary. Westach makes a dual gauge for use with two sending units. I have it bookmarked on my home computer...but it's currently about 1400 miles away. If you're interested and don't find the info before I get back from vacation I'll try to remember and post a link.

I have the sender in my Dodge on the output line from the trans for now. I like knowing when to downshift or back out of the throttle when things get too warm in there, but plan on swapping in the dual needle unit so I can watch the temps on both ends.

[bitman]

Dan,

Please post up your solution; if nothing else, someone else may benefit.

I've already got the digital gauge and sender installed on one line; just need to install another sender and switch.

Thanks,

Dave

[DanB98TJ]

Dave - Westach's website is http://www.westach.com , but I didn't see the gauge I was looking for there.

I'm pretty sure this is the one I have bookmarked at home, though:

Dual temperature gauge

[svandell]

Originally posted by DanB98TJ
Dave - Westach's website is http://www.westach.com , but I didn't see the gauge I was looking for there.

I'm pretty sure this is the one I have bookmarked at home, though:

Dual temperature gauge

I have the Westach dual sender gauge. It works great. I got them to label "trans" on both temperature scales also. The Westach guys were nice to deal with.

Scott

[jbolty]

Hey all, I was swapping emails with Jerry about this and he sent this link to me.

Would it be better to have the temp sender in the line from the cooler or in the pan? Seems like the pan would be ideal to really know the operating temp.

I curently have a perma-cool add on filter with the temp sender in the side come out of the trans. (TF999)

THANKS

[Lawrence]

Originally Posted by jbolty

Hey all, I was swapping emails with Jerry about this and he sent this link to me.

Would it be better to have the temp sender in the line from the cooler or in the pan? Seems like the pan would be ideal to really know the operating temp.

I curently have a perma-cool add on filter with the temp sender in the side come out of the trans. (TF999)

THANKS

Ideally, you'll want to have the sender read the temps for the hottest part, so you can keep an eye on it. Having it in the pan, or in-line as close to the exit from the tranny would be better. The better choice would be to add a second one in-line after the cooler to monitor your IN & OUT temps, therefore your cooler's efficiency.

[jbolty]

Makes sense to me. I just ordered another sender so I think I will put that in the pan.

The current one is part of the external filter housing so if I leave that there I can get the max temp from the torque converter then in the pan I can know the actual operating temp of the trans.

Thanks for the info

I'll report back