68RFE Transmission Temperature

[lgill]

I just purchased a 2012 Longhorn 68RFE and am questioning the transmission temperature at hwy speed. My old 2001 3500 47RE ran 160 to 165 deg F consistantly at hwy speeds. The new 68RFE is running 181 to 185 deg F at hwy speeds. Driving conditions were the same, a hot summer day in FL; 97deg F. Is this normal? I am concerned what will happen when I put our Lance 1191 slide in camper (heavy) in the bed and hit the road in July. Another difference is my 2001 had a 4:10 rear end and the 2012 has a 3:73. Any advice would be appreciated. ... Lynn T gill

 

[mpaulson]

I don't know where the OEM sensor is on the new trucks, but on my 68rfe I have the sending unit in the hot line out of the transmission before the cooler and I see an average of 130 to 200 F routinely while at 24,000# total with lots of wind drag. The normal hiway crusing temp loaded is about 160-170F loaded. Empty is only about 10 degrees cooler or the same in city driving. I did see 260F once while climbing a slow switch back road with the load. I have about 175,000 Km's and have done nothing but service the transmission every spring. I would say that you have absolutly nothing to worry about.

 

[lgill]

Thanks Mpaulson as now I will sleep better. It was the running temperature difference between my old 2001 and the new 2012 that spooked me a bit.

 

[rwitt]

I just got back from a trip east on I-80 through the Sierras, then North on 395 to Susanville/Eagle Lake with the camper on the truck, flat towing the Jeep. I have the Edge Insight gauge on the truck, and the highest trans temp I saw was 172* pulling the grades. Mostly it was in the 160 to 165 range. Outside temp was mid to upper 80's.

Rich

 

[Cummins12V98]

Trip from Palm Springs to Pahrump, NV May Madness 80 outside temp grades to over 6% 162 degrees, 90 outside, temp was 172 same grades. AMZ/OIL in trans and Mag Hytec pan. That trip is uphill most of the way. I was impressed with temps. 27,000# combined weight.

 

[lgill]

I am using the factory installed gauge and readout located in the middle of the dash and I question it's accuracy. I plan to order the Edge Insight gauge pack from Geno's as soon as I recover from the sticker shock of purchasing the truck. Thanks for the input. ... LT

 

[mrkstrk]

The 2012 transmission operating temps can NOT be compared to any prior years. If outside temp is warm enough, operating empty and long enough the trans temps will match the engine temps. Go online and read about winter cold operating problems with the 68RFE and look at the trans cooler line routing thru the coolers and the "thermostat", it will answer all your questions.

 

[Cummins12V98]

The 2012 transmission operating temps can NOT be compared to any prior years. If outside temp is warm enough, operating empty and long enough the trans temps will match the engine temps. Go online and read about winter cold operating problems with the 68RFE and look at the trans cooler line routing thru the coolers and the "thermostat", it will answer all your questions.

When you say "match the engine temps" are you saying the trans will be at 200-203 like the engine under normal conditions? Read my earlier post, my trans temps never come close to the engine temps under all conditions whether it is towing, solo hot out or cold. I have read other peoples trans temps being higher than mine but not that hot. Are you saying 2012 HO is different than 2011 HO trans temps? As far as I know they are exactly the same.

 

[sag2]

The transmission temp displayed in the cluster is from the thermister located on the valve body. It should be VERY accurate. The Edge will most likely read the temp from the same place as I do not believe it has a temp sending unit included.

The new cars and trucks (2013) have technology in place to get the temps up to operating temp as quickly as possible. It saves on fuel from frictional losses being reduced from high viscosity of cold fluids.

As far as what is too hot, until you see upwards of 260 you are degrading the life of the fluid, but not doing any harm to the transmission. You will never see temps anywhere near that unless you are going too slow to keep the converter locked. Starting in 2010 the thermostats were raised about 10 degrees from the earlier trucks. The cooling package for both the engine and transmission of the newer trucks is very robust, and rarely needs to be improved upon if CGVW limits and common sense is observed.

 

[RonD]

I just purchased a 2012 Longhorn 68RFE and am questioning the transmission temperature at hwy speed. My old 2001 3500 47RE ran 160 to 165 deg F consistantly at hwy speeds. The new 68RFE is running 181 to 185 deg F at hwy speeds. Driving conditions were the same, a hot summer day in FL; 97deg F. Is this normal? I am concerned what will happen when I put our Lance 1191 slide in camper (heavy) in the bed and hit the road in July. Another difference is my 2001 had a 4:10 rear end and the 2012 has a 3:73. Any advice would be appreciated. ... Lynn T gill

Your 2012 has a trans cooler system a little different than your old truck, the engine runs warmer than your old one, the cooler is two, one is oil to air, the other is oil to water, your engine coolant is warmer, so your trans will be warmer, there made to run at that temp, you will notice it won't get hot as the older ones could at times, I have pulled 15 mile long 6-7 % grades in 90 degree temps, combined weight 23000 pounds, never could get it over 196 degrees, enjoy your new truck.

 

[lgill]

As for enjoying the truck; I plan on doing just that. We only have 15 hours on it so I am still getting accustomed to the new noises and feel. The only option I need soon is a TV monitor in the cab that will talk to the camera on the Lance camper, but that is another post. Again, thanks for the information as I really appreciate it, ,,, LT

 

[Beast2B]

I added a Lockpick CHR550 to add and control multiple cameras through the factory head unit. Also unlocks the DVD and NAV in motion controls. Pretty simple install and very easy to use. http://www.coastaletech.com/CHR550.htm (I went to EBay)

 

[Cummins12V98]

I added a Lockpick CHR550 to add and control multiple cameras through the factory head unit. Also unlocks the DVD and NAV in motion controls. Pretty simple install and very easy to use. CHR550 LOCKPICK (I went to EBay)

I just want to be able to control the Nav system when driving. What product is best for that?



Thanks

 

[lgill]

Thanks for all the information. I am still coming up to speed on this truck as I just topped 400 total miles where as my old truck had 155K miles and I knew every noise and quirk it had which gave me that warm fuzzy feeling. With time I will develope the same comfort level. Beast2B, thanks for the info on the Lockpick CHR550 as it looks like the way to go.