Well I thought I'd share my findings on trans temps delivering hay lately. Been hauling the same size load on same road, made four trips over the last month or so for this example. Most of my other deliveries are closer to home and trans never gets warmed all the way up. Trailer is weighing in roughly at 15,000 and making a 70 mile each way trip at 55-60 mph.  Takes a little over half way through the trip to reach its towing temp of about 190°. Running empty I usually see 150-160°. Temp probe is in drivers side pto cover, I installed it when I changed trans fluid to amsoil in the spring. I did however take the expressway home today because I was running short on time and had to get to work and was surprised to actually see temps around 200-210° with just empty trailer running 70mph. Just sharing some of my experiences and wondering what some others might be seeing. I would like to try a fast cooler in the future and see if there's any temp drop but for this summer probably will stay stock. 

 

Sorry the pic isn't the best but you get the idea. 

I don't run a temperature gauge, but I do run fast coolers and have wrapped my down pipe. The down pipe being wrapped has reduced the floorboard temps so I am sure it has helped the trans temps too. 

 

I'm not sure probe placement is as critical as some suggest since the fluid isn't stagnant when  you are driving. All the gears moving in there will slosh and mix it all around. 

 

From what I have read overfilled transmissions run hotter than standard fill transmissions, and there are a couple theories. One is that the additional fluid does a better job pulling the heat from the gears/bearings so the fluid is hotter but the gears/bearings are cooler; and the other is that the additional fluid doesn't have the splashing inside the case and thus loses some of it's ability to cool and makes the gears/bearings and fluid all run hotter. 

 

I think theory one is the most widely believed. 

 

I know the NV4500 has some 5th gear nut issues and that started a scare for towing in 5th, but the NV5600 doesn't have that issue and can tow in top gear... As far as temps OD will almost always run the hottest. I've personally never heard of cooked fluid or bearings on a NV4500 or NV5600 and only a few cases with a G56 and ATF. 

 

I'll continue to use 6th when I have the power to do so. 

Just to be clear on my "overfilled" statement.....  The 4500 holds 4.25 qts.  The Fastcoolers hold 1 qt per side.  Therefore I have about 1/2 to 3/4 of a qt in there overfilled.  The way I read what I posted was 7 qts overfilled and I dont want anyone to think I'm running almost 2 gallons overfilled. 

I'd edit it but no longer can...

23 minutes ago, KATOOM said:

But that said, if you tow only in 4th gear you'll never have a heat problem

 

To cover all platforms. Direct 1:1 ratio is...

• N5600 - 5th gear
• NV4500 - 4th gear
• 47RE - 3rd gear

For towing up grades this is the coolest gear to use. 3rd gear will enhance the heat because of the long time pulling the grade at a slower speed giving more time to heat up. 5th gear from pulling with high torque in a overdrive gear will create considerable amount of heat too. 

2 minutes ago, KATOOM said:

I'd edit it but no longer can...

 

12-hour window. After that, the system locks out the edit. Prevent members from thrashing their posts.

37 minutes ago, Mopar1973Man said:

12-hour window. After that, the system locks out the edit. Prevent members from thrashing their posts

I see where you're going with this lol

My intent wasn't to go over the deep end @Mopar1973Man! Just sharing some of my results and seeing what other members had observed to see if it was in line with mine, or close for that matter. For the record I'm on stock tires, 4:10 gears and factory fill level. 

 

On a side note I may look into the heat wrap because the wife doesn't really care for how warm the floorboard gets on her side wile towing!