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-   -   Max Chevy Trans Temperature (https://www.forestriverforums.com/forums/f12/max-chevy-trans-temperature-9989.html)

Herk7769 01-08-2011 08:46 PM

Max Chevy Trans Temperature
 
Maximum transmission temperature

In the February 2011 issue of Trailer Life magazine RV Clinic in response to a reader about the maximum transmission temperature allowed in a 2009 Chevy Silverado, the Tech Team had this response.

“General Motors’ in-house towing team expert provided RV Clinic with this statement: The maximum allowable automatic transmission fluid temperature is dictated by the transmission oil itself. The oil begins to degrade significantly above 270 degrees Fahrenheit, so we design vehicles so that in all but the most extreme conditions, the fluid temperature in the transmission sump stays below 270 degrees F.

We allow for up to 285 degrees F in extreme conditions (i.e. towing a trailer with combination loaded at GCWR in Death Valley). But for customer usage anywhere else in the country, even at GCWR, transmission sump temperature should stay well below 270 degrees F. Above this point, certain internal components, such as seals, begin to disintegrate rather quickly. Although newer synthetic fluids can withstand higher temperatures we still recommend this (270F) as a maximum temperature. "

Traveler II 01-08-2011 09:13 PM

Good to know Lou, I was told by my dealer to keep it below 212. Glad to see there is some leeway.

hoffkm 01-08-2011 09:41 PM

270 degrees initially seemed a little high to me as I have always targeted a maximum of 200 degrees on my fluid temp. In the machines that we build at work we target 150 degrees for the hydraulic oil and have problems when we get up in the 190-200 range with varnishing of pumps and valves. I did a little research thinking that maybe GM was referring to new vehicles that are utilizing synthetic oil as all GM trucks do since GMT 900 in 2007 (much higher operating temps than traditional "dino" oil). I found that transmission oil starts breaking down prematurly at temps above 175, damage occurs above 300 to internal transmission components, and as high as 275 is allowable for all transmission fluids. However, it you run temps above 175 (as we all do towing our rigs) more frequent fluid and filter changes are required as outlined in the following chart (validated from a couple of sources):

175 degrees change every 100,000 miles
195 degrees change every 50,000 miles
215 degrees change every 25,000 miles
235 degrees change every 12,500 miles
255 degrees change every 6,520 miles
275 degrees change every 3,125 miles

Sorry for all the boring data, guess it's the engineer in me coming out.:rolleyes:

acadianbob 01-08-2011 10:58 PM

LOVE the engineering data! Very useful. I rarely exceed 160 degrees on my F150 though. Exception is a 10 mile climb of 5 go 10% in the mountains. Then I see 205 by the end of the climb.

crocus 01-09-2011 12:39 AM

I put the biggest tranny cooler I could find on our TV, and the temp never goes over 160, usually around 135. No sense cooking the oil in a vital TV component.

bikendan 01-09-2011 03:36 AM

i'm interested in this discussion.
i have an '07 Avalanche, with factory tow package, pulling a 23' HTT that weighs a little over 5000lbs.

i've had tranny temps around 225 degrees for short climbs.
i've wondered if this was normal. the factory tow package has a tranny cooler in it.

MtnGuy 01-09-2011 07:53 AM

Quote:

Originally Posted by acadianbob (Post 77275)
LOVE the engineering data! Very useful. I rarely exceed 160 degrees on my F150 though. Exception is a 10 mile climb of 5 go 10% in the mountains. Then I see 205 by the end of the climb.

My temperatures are simaliar......imagine that since we have the same truck stats. :p

Check out this thread: https://www.forestriverforums.com/for...hart-3427.html

That new Google search engine at the top of the page works sweet. :)

Herk7769 01-09-2011 08:02 AM

Chap, that is why a started a new thread and "stuck it" This was the first time I had ever seen the "maximum" temp confirmed anywhere. The DIC warning comes on at 250 and you should take quick action to pull over and cool down before continuing.

hoffkm 01-09-2011 08:54 AM

Quote:

Originally Posted by bikendan (Post 77288)
i'm interested in this discussion.
i have an '07 Avalanche, with factory tow package, pulling a 23' HTT that weighs a little over 5000lbs.

i've had tranny temps around 225 degrees for short climbs.
i've wondered if this was normal. the factory tow package has a tranny cooler in it.

The factory tow package transmission oil cooler is no more than the stock cooler that flows thru the radiator. Before I towed anything with my 2007 Avalanche I added the GM auxilary cooler in front of the radiator. With this my trans temp runs between 170 and 190 pulling my 2901SS and may get to 200-205 if I am pulling up an incline. An aftermarket cooler may work even better than the GM accessory item.

rockwood06 01-09-2011 10:19 AM

1 Attachment(s)
I had posted this chart a while ago, it shows the break down of the trans as the temp increase over a period of time. I have a read out on my truck that tells me what the temp are on the trans from the factory.

Herk7769 01-09-2011 10:56 AM

I printed your chart and have it laminated in the truck.

rockwood06 01-09-2011 05:21 PM

Quote:

Originally Posted by herk7769 (Post 77329)
I printed your chart and have it laminated in the truck.

herk7769, I am glad that is what it is there for and hope it helps others keep an eye on things. :thumbsup:

acadianbob 01-09-2011 06:56 PM

OK, so what do these temps mean? It seems to me that a temporary spike to a temp is a lot different than a continuous run at the same temp. So, for example, when I hit 205 at the end of a big mountain climb, but otherwise run about 155, I would think there is not much reason to be concerned. If, on the other hand, someone ran 205 all day for a couple of days, that would be a whole other thing. That temporary spike is unlikely to shorten transmission life I would think.

Herk7769 01-09-2011 08:10 PM

Bob I feel the same way. The idea is to monitor the trans temp and pull over when it gets too hot. What had been missing was the yard stick of "what is too hot".

Hipshot 01-09-2011 08:43 PM

Thanks Lou. I asked my dealer service department what the max temp was when I bought the truck and they did not know. They "thought" 220 was max. I did not know until your post that the DIC gives an alarm at 250. That is good to know. On our trip to Big Bend last spring I had a long climb into a strong headwind. The trans temp got to 216 and worried the heck out of me. Knowledge is good, thanks again.

MtnGuy 01-10-2011 09:08 AM

According to Wade's chart, it lists the average temperature. I interpret that to mean if your tow vehicle runs 200 degrees all of the time, expect the transmission to last ~80,000 miles. Now that being said, I realize a huge spike in temperature could break down the transmission fluid some, and cause problems. I can't think that the low 200s for short periods of time would be too bad.

Herk7769 01-10-2011 09:11 AM

Chap's point is well taken. I keep my Driver Information Center (DIC) on Trans Temp while towing just so I know what is going on there. Forewarned is forearmed. ;)

DDC 03-31-2013 07:59 AM

Just browsing and came across this thread. https://bmracing.com/?wpsc-product=hi...2-diameter-fan
I installed one of these in my Avalanche under the radiator in the pocket behind the bumper, it does not need any direct air flow as the fan does all the work, it came with a temp switch but I installed a switch to operate it manually. It is amazing how cool it keeps the transmission, on long climbs I switch it on and the temp stays around 63-67C (145-153F) if left on just towing I get temps around 43c (109F).

RetirededTX 03-31-2013 11:32 AM

1 Attachment(s)
Right after I got my 2006 Dodge 3500 Diesel I was doing some extreme backing maneuvers with my utility work trailer (8x16 and about 8K#s with every tool I own). My customer was in a rural location, up a hill, with no place to turn the rig around if I just pulled in, so I backed about 150 yards up her twisted driveway. As I was completing this problem the transmission overheat indicator came on. That was enough incentive for me to find a cure. I researched it to death, and purchased a kit from ProWeld Performance Parts which uses a B&M Hy-Tek cooler (info link: https://proweldperformanceparts.com/S...hreeYears.html ) The price has gone up since I got mine in 2007 but Iíve never seen the light again, and that includes towing our 5er to California and back in July. The fact is, Iíve only seen the fan come on one time, and it was during that trip (something about a long grade, stuck behind an 18 wheeler, and over 100 degrees OAT). IMHO the extra oil, and cooler, not in the engine compartment has added a lot of cooling power to the transmission anti-destruction system for daily use, but most importantly for those cases where itís nice to not have to stop and let things cool down.
I've include a pic of my installation, looking forward from under the rear seat area.

TURBS 03-31-2013 12:17 PM

Doesn't the Allison/gm go into limp mode and de-fuel when trans overheat occurs?
The 08 duramax for sure has the cooler mounted underneath the truck and just ahead of fuel tank..
I wonder how optimal that is ?
I've been looking for a small shrouded fan to mount on it but its a pretty small cooler@ 8-1/2 by 10-1/2.

Turbs


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