I have a 2011 Ram 1500 with the 5.7 liter and 3:73 rear end . I just bought a 5th wheel with a dry weight of 8100 lbs .My transmission temp sometimes reaches 230 Fahrenheit .Is this safe ?It appears that I was wrong about the rear end . It is a 3:55 . I should probably add that the 230 degrees was on a hot day and going through hilly terrain . On flat ground my truck usually hovers around 200 . It has the tow package with tranny cooler installed .

 

1st off - no such thing as 3.73 in a Ram. 3.21, 3.55 or 3.92 are your options




That seems way too high. Do you know what the actual weight of the trailer is? Advertised dry weight isn't particularly useful.


Once you figure out what your gear ratio is, weigh the trailer and look at this chart.


http://www.ramtrucks.com/shared/pdf/..._Tow_Chart.pdf

 

I have a 2011 1500 5.7 and even when it's 90 degrees out and i'm in traffic i never see temps above 170. I believe the warning light comes on around 245 degrees on these trucks (The dealer told me that, so take it or leave it). I do know that temps as high as you are seeing are not good.

I have a friend who tows a 6k trailer with his 10' 1500 and he told me the hottest he ever saw under average driving was 205.

If your trailer weight is accurate EMPTY then certainly you will be adding enough weight with personal items, water, food, etc that you will be either overloading your truck or simply running it at full capacity. Opinions vary, but i think most will agree that running a truck at capacity is not something you should do on a regular basis. Your transmission temps seem to agree with that.

You could add an auxiliary cooler to help bring the temps down a bit more, but perhaps a towing guru on this forum can really shed some light on the issues at hand.

 

assuming you have the 3.92 axle ratio, you are still probably at the limit causing a lot of transmission shifting. What I figured out to keep the temps lowered was to watch the RPMs carefully while playing with the gear selector to figure out when the TC was locked versus unlocked. Trans runs much cooler when the TC is locked. I normally put it in TOW/HAUL and lock out 5th gear when towing unless I have a tailwind or on a down grade, then I allow 5th. In my case, I noticed that the TC would unlock and the RPMs would go up, I then select 4th and the RPMs would change which told me I was in 5th, eventually, in 4th gear, the TC locks up, the RPMs settle down to a lower number than in 5th with the TC unlocked and after 5 to 10 minutes, the trans temps go down. Hopefully this makes sense to you.

If you are seeing 230 for long stretches, change the trans fluid as soon as you get home.

 

Are you towing on flat roads or hills/mountains? Lots of wind?

I towed a trailer that was probably at the upper limit of towing capacity on my 2010 1500 through some significant mountain roads (Chief Joseph Highway, Big Horn mountains 14A) a couple years ago. Highest trans temp I saw was about 220* for a while on the 10% grade sections of 14A. With the 5 speed trans in my truck it was either roaring along at high RPM in 2nd or lugging if it shifted to 3rd.

If you're seeing 230* regularly on relatively flat roads that seems like a problem.

Rob

 

ATF-4 is more heat tolerant compared to Dexron-Mercon, but I agree with the previous posters that 230F is on the high side. On my 2010 Big Horn with 545RFE tranny and 3.92 LSD, I saw temps climb to 190F once towing 9600 lbs. after about 125 miles. I used the Tow/Haul mode only on steep hills. I suspect you might be towing more than you think you are in weight.


When you are towing at or near your trucks towing limit, you should be in the Tow/Haul mode most of the time. This is particularly acute in hilly country.


Now on my 2014 Big Horn with 3.92 LSD and 8HP70 8-speed transmission, the transmission temperature comes up to 206F very quickly and just hangs there forever regardless.


Best regards,
Dusty


2014 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 8HP70, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 004500 miles.