14 replies to this topic

[terzmo]

My Son just bought a new silverado...Z71 with the tow package....what is normal operating temp of trans towing vs non towing...It usually runs around 145 to 150 when NOT towing but in alot of stop and go has hit 160..

[oldschool327]

That is perfectly normal.

[VMax626]

Yeah, it is at normal operating temperature.

[terzmo]

Yeah, it is at normal operating temperature.

Thanks..but what is the temps supposed to go to when towing in hot weather or hills ??

[music]

I just got back from towing our (7k lb) camper to Destin, FL (from TN). Ran 60 to 65 mph (sometimes found myself faster). Transmission temps ran right at ambient +100F (i.e., 90 ambient would be 180 to 200, depending on hills). Averaged 10.7 mpg round trip... and that's with quite a few "2nd gear" hills @ 65 mph and trying to accelerate uphill while merging into hwy traffic. All in 3rd (didn't use 4th).

[c03camson]

Towing the boat this passed weekend I saw my temp hit 171 and it was 94 outside. Thats the highest I have seen it. In the manual it says normal temp is 160-180.

[NickV]

I got my 6 speed automatic up to 210* last week towing a 4,600 travel trailer with about an extra 1,000 lbs. in the truck bed.

that was the peak, for the most part it stayed just below 200*

[terzmo]

I just got back from towing our (7k lb) camper to Destin, FL (from TN). Ran 60 to 65 mph (sometimes found myself faster). Transmission temps ran right at ambient +100F (i.e., 90 ambient would be 180 to 200, depending on hills). Averaged 10.7 mpg round trip... and that's with quite a few "2nd gear" hills @ 65 mph and trying to accelerate uphill while merging into hwy traffic. All in 3rd (didn't use 4th).

Thanks...My Son couldn't find any temp specs in His 2010 manual

[Rod R]

try to keep your transmission temperature to 195*F maximum
.. back off on the accelerator if the transmission temp is climbing past 195
.. and then get an external transmission cooler (or if you have one, get a bigger one)

if you are running your transmission at higher than 195, then you starting to cook the internal parts, which causes them to breakdown faster, and you are also starting to breakdown the oil.

Edited by Rod R, 07 June 2010 - 02:36 PM.

[music]

I've seen the 200F temperature mentioned on numerous towing threads, but I've yet to find engineering specs to support it. The latest full-syn fluids perform at higher temps without degradation, yet the old charts from aftermarket cooler manufacturers/sellers don't account for it. The "high" numbers I've seen from engineers on the topic have been in the 240 to 250 range, with "limp mode" kicking in around 260F. I had to search, but dug up this interesting post a while back, just for interest. I'm not arguing the topic (as I don't really know myself)... just tossing out more info to consider. I personally believe the GM towing specs w/ the stock cooler, as they test the setup in freezing cold, blazing hot and at high altitudes.

Trailer Life Forums: Transmission Temps

... As for temperatures the transmission was designed to operate at about 180°F. There is NO damage from heat at 175°F, nor is there any at 220°F. Don't show me that chart that says otherwise. It was either developed from 1960's materials or it was designed to sell transmission coolers. Nothing that is listed on that chart really happens to modern transmissions. Ford designed the 4R100 to be able to run at 220°F all day long with NO damage. It can go to 250°F for no more than 1/2 hour with NO damage.

Mark
Former Ford Automatic Transmission Engineer, 1988-2007

Edited by music, 07 June 2010 - 08:55 PM.

[music]

One more comment on fluids. GM recommends 50k mile transmission fluid changes for "harsh use". I only tow a few times per year, and normally run 175F to 195F doing so. 80% of miles are "normal, unloaded driving". I still intend to follow the "harsh use" schedule for fluid replacement. Cheap insurance...

Edited by music, 07 June 2010 - 09:20 PM.

[pm26]

So, about 360 degrees Kelvin is normal transmission operating temperature?

[txab]

So, about 360 degrees Kelvin is normal transmission operating temperature?

That would be about correct

[terzmo]

One more comment on fluids. GM recommends 50k mile transmission fluid changes for "harsh use". I only tow a few times per year, and normally run 175F to 195F. 80% of miles are "normal, unloaded driving". I still intend to follow the "harsh use" schedule for fluid replacement. Cheap insurance...

great stuff..thanks to all for the input

[sabre364]

You guys should see the dodge jeep maint schedules. 15k is the harsh driving for diffs/tcase, i have seen as low as 12k quoted in the manuals. Easy driving for diffs/tcase/plugs is 30k. Trans is 60k, coolant 60k

One more comment on fluids. GM recommends 50k mile transmission fluid changes for "harsh use". I only tow a few times per year, and normally run 175F to 195F doing so. 80% of miles are "normal, unloaded driving". I still intend to follow the "harsh use" schedule for fluid replacement. Cheap insurance...