Transmission temps.

Restless · 09-15-2009, 05:44 AM

While travelling to the M & G this past weekend, I looked at the transmission temp. to find it was registering 90 celsius (we're Canadian).
When we returned home, I converted the temp. to find that it was 190F.

I believe this is correct, but it seems really high. Should I be concerned, or am I wrong on this?

We may be going to the Adirondacks next week, and I would bet that the temps. will be higher there due to the terrain.

Thanks

**Sunline Fan** · 09-15-2009, 09:32 AM

Mine doesn't read an actual trans temp, but I've never seen it ever budge from the normal spot, even when towing.

I have a ScanGauge II that I have mounted on my dash and just recently I figured out how to program in for it to read trans temps. I've yet to tow with it since I did that, but right now on the highway solo it runs about 150-160. I guess I'm not overly surprised that it would be 190 when towing. Right now I get on the highway and it gets in overdrive and doesn't really leave it unless I have to slow down for something, so I could imagine if it did a lot more shifting that the temp would climb. When I initially got the thing programmed, I took it for a ride to try to see what the range would be. I went for about two miles and ran it hard (slowing down, stomp on it, etc) to make the trans shift a lot. This of course was all (rural) city driving, not highway. I don't remember too much now, but I think I got it up to 184 or 186 in doing that.

I am curious as well to what the suggested temp range should be.

Jon

DF5.4 · 09-15-2009, 12:42 PM

I had a transmission temp gauge in my F-150. 190 degrees when towing is fine. I used to see 220 when climbing hills then it would come right back down when I was done climbing.

Here is some information that I found.
http://www.digi-panel.com/digidevicesweb/trannyoil.htm
http://www.tciauto.com/Products/Tech...expectancy.asp

**JohnB** · 09-15-2009, 10:31 PM

John

On my prior K2500 Suburban, 6.0 with the 4.10 rear end, mine ran 190F all the time towing. It would stop at about 200 and just hold there even on hot summer days. The 190 is normal and I was towing in 3rd gear tow haul on.

The only time I had it up to 235 and even worse 245 was coming home with the new T310 empty in the hills of PA that would not give up. There was no recovery. GM’s just run hotter. I have the shop manual and all it says is, when towing change the fluid more often…. So I changed the fluid once a year when towing.

GM's tranny gages are more sensative then Fords. Fords do not move much until they are way over the norm. Plus Ford has no graduations to even know what it is anyway. At least on my F350

I'm curious on how Sunline Fan got his scan gage to read tranny temps. I can't on mine and wish I could. Mine will not find the pan sensor code.

Hope this helps

John

**Sunline Fan** · 09-16-2009, 06:57 AM

GAUGE: Transmission Fluid Temperature (deg F)
TXD: C410F1221674
RXF: 046205160674
RXD: 3010
MTH: 000100080000
NAM: TFT

That's the code to program it into the ScanGauge. You'll have to read the manual on how to program in codes, but it's pretty easy. I don't have time now and I don't have my manual with me.

Once you do it, you can push the little buttons on the side for the position you want it in and TFT will show up as a choice now.

Jon

Honda03842 · 09-16-2009, 10:25 AM

We have a Bounder with a Ford 460. I am very conscious of Transmission fluid temperature. The Ford manual reccommends changing the fluid every 25,000 miles.

As well I look at the oil level at the start of every trip no matter the length and at the same time check the transmission fluid to make sure it has changed from pink to brown. Burnt transmission fluid is a quick death for a transmission.

Paranoid Norm

**Sunline Fan** · 09-16-2009, 11:08 AM

Here's a few pics of the ScanGauge in action. I took the pic just after starting, so these are cold temps.

I have never figured out why the dash trans temp gauge shows like it's almost up to temperature when it isn't. It's always done this, and the other one takes forever for the gauge to move, yet with the same temps.

It'll show all the way at the "C" when it's been colder, like in the 40's or 30's overnight.

Now here I changed to show the incoming air temp, just so y'all can see what it is and what temps result. I think it is pretty accurate right now. The computer in the vehicle showed 66 though, which I know is more than what it currently is here.

Jon

**Sunline Fan** · 09-21-2009, 03:51 PM

Had the opportunity to pull my coach out for a night this weekend. Only pulled it 16.2 miles each way, and mostly rural roads @ 55.

The last 1.5 mile part of the trip out involved me climbing a hill for about 3/4 mile from a dead stop. The temp got to the high 180's then (I think it was 18

, but by the time I got parked, this is where it was.

Jon

rich2500 · 09-21-2009, 06:22 PM

Jon wait till you get an oppurtunity to tow up one hill and down another then up another exc.exc. you will see the temps hit 200degs. plus. My f-250 used too until I installed a second tranny cooler,now my temps don't get out of the low 190's no matter what.The scangauge is awesome I don't even need to look at the other gauges in the truck except the fuel gauge.To the OP 190 tranny temps are totally normal when towing just change the fluid once a year and you should be fine.

Restless · 09-22-2009, 05:54 PM

All the info about the temps was great. Now when it hits 190 or above I won't be waiting for smoke wafting from the engine compartment. Going camping this weekend so I can put my confidence to the test. Thanks to all for the assistance.

henryj · 09-22-2009, 07:30 PM

Hey John and Kim,
Check your inbox under the messages link. I sent you a pm about my experiences as I thought this thread had changed direction.

Henry

Skyraider50 · 02-11-2012, 10:55 PM

I love bumping these older threads. After reading several threads on the subject, here's the deal.
I am using a 2005 Nissan Titan which I am sure is a 1/2 ton pu. I added a Tranny cooler and it is equipped with a "tow mode" button which according to the manual raises shift points somewhat to facilitate better performance while under tow.
That having been said, I did a short tow the other day to shake down my New 2000' Advancer T-25R. Reported to have a Dry weight of 4200 pounds and a GVW or 5500 pounds.
Had no problems as it was a short tow. I reading the other threads I assume that using OD if it wants to slip in and out crossing overpasses or minor grades is a No, No?
SO I guess I must ask....towing speed? Better just to back off the throttle a bit to say 60 and keep the tranny in third and not try to use OD. Does using the third rather than OD have any negative effects (other than mileage)
I believe at 60 in third, I am running 2000...ish maybe 2200 RPM.
Love to have some input from some you long time haulers....
Thanx!

mainah · 02-12-2012, 07:12 AM

I was a shop manager of a large transmission shop years ago and we would not warranty a motor home trans unless we added a external cooler it is a great add on for any automatic that is used for towing the bigger the better. The trans is going to run close to engine temp after all is is attached to it. What causes high trans temp is converter slip. All converters slip (except for lockup types but only when they are locked) so to avoid slip use lower gears when climbing and skip O/D unless it pretty flat. Lockup converters unlock first when there is strain on the drive train then they will down shift to a lower gear with more strain. 25K to 30K is a good time to change trans fluid and flushing it with a complete refill is the way to go. I would also recommend synthetic fluid it does better with high temps.

**JohnB** · 02-12-2012, 07:54 PM

Hi Sky,

Check your owners manual. Some trucks use to not allow to you tow in OD at all. And yes if it keeps hunting in and out of OD regardless that is not good. On my prior K2500 Suburban 4 speed I use to put it in tow haul and in 3rd gear and just tow. While the truck manual allowed OD it kept hunting at the slightness grade. I can buy a whole lot of gas for the price of a tranny problem.

In the F350 it has a 5 speed torque shift transmission with tow haul. Totally different then my old 4 speed GM. 4th and 5th are not accessible to the operator so I do not a lot of choice, I just use tow haul and tow. This transmission reacts different. I have not yet 100% figured it all out. The computer selects when to drop it into 5th gear and it is not speed related. I can be running 1,750RPM doing 50, 55 or 60 mph. The truck senses drag and it will drop to 4th and hold there, 2,200rpm and then slip back into 5th and 1,750 when the drags goes away. If I am hitting a head wind it will not go to 5th.

As far as towing speed, 60 mph is the top end of what I do. 58 is about the shift point most times it drops it into 5th and my engine torque curve is pretty flat up in that area so she just pulls. The truck can do a whole lot more but reaction time and risk goes up along with speed. Not to mention in the state of Ohio towing speed limit is 55. Each state is different.

And I totally agree with mainah on changing the tranny fluid. If you are towing it is cheap insurance for the longevity of your truck. GM would not even give a recommendation on mileage. In the shop manual all they declared was if you tow frequently, change the fluid often. They never declared what often was and how much towing was a lot. So I picked 25 to 30K.

John

Skyraider50 · 02-12-2012, 08:18 PM

THANX guys for the good counsel guys! I am already running synthetic as my mechanic told me some time ago, that was the way to proceed. Should be good on the mileage, but in the next couple of weeks, I'll get a flush and fill....as yes you can buy a lot of fluid for the price of a tranny job.
Taking a trip this weekend to Hillsborough State Park east of Tampa...3 hour trek. The Titan is not overly stressed, BUT I like to it as easy in the machine as I can. I'll review my manual again for towing info......