Matt S

I'm driving out west towing our camper. I have a set of fast coolers, added an extra quart from the top of the tower, and have a gauge on my transmission. I thought my probe might be going bad with the high readings I've been seeing but after searching the forums I think it might be working. Yesterday I saw 280* on the gauge.

Is this normal? Are the fast coolers enough? I've noticed there is another alternative from trans-cool.

Last fluid change was 53,000 miles ago with the stock synchromesh fluid. The truck has 153,000 miles on it.

carl48

the trans-cools work better than the fast coolers. blend the following two oils in a 50-50 mixture and fill the transmission until it runs out the plug then add two more quarts. one is royal purple brand, the other is delo, you can sub Castrol syngear CD50 for the delo that you can get from o'rileys or the delvac from wwgranger
Delo Synthetic Transmission Fluid SAE 50 delivers exceptional all-climate, year-round performance in heavy duty truck transmissions. A unique additive package can protect gears without using the “active sulfur” agents commonly found in automotive axle oils. This results in little to no corrosion and long life for copper-containing parts, such as oil coolers, bushings, and thrust washers. Good pumpability in extreme hot or cold temperatures promotes smooth shifting and efficient power transfer. It is specifically formulated to meet the latest extended drain requirements for Eaton transmissions, with drain intervals of up to 500,000 miles.
Synchromax is recommended for manual transmissions
that specify an automatic transmission fluid or motor oil.
It is also ideal for transfer cases and 2-cycle motorcycle
gear boxes.
Synchromax is formulated with Royal Purple’s synthetic,
proprietary Synerlec additive technology, offering
improved shift quality over a wide temperature range and
reduced gear noise.
Synchromax is fully compatible with all types of friction
materials and offers excellent corrosion and oxidation
protection without affecting the soft metals commonly
found in manual transmission synchronizers.
Performance Advantages
• Greater wear protection
• Smoother shifts
• Excellent rust / corrosion protection
• Reduces friction for more power
• Lowers operating temperatures

Matt S

Thanks for the trans-cool suggestion. I'll look into that. I'm wondering if I can use both the trans-cool and the fast cooler.

I looked into the royal purple and compared the product sheet with the Pennzoil. It looks like the Pennzoil has better numbers.

C Schomer

Why mix? Mine works great with 6 qts RP alone. 220degrees max.

jhenson

Granted, I never checked my trans temps.....but I use to haul HEAVY and I never had an issue with my 5600. I CAN say that things use to get hot because when I would come in from a haul and go to the car wash I always got steam from the rear diff and trans area which told me it WAS hot and things should change. Before I had a chance to change to synthetics and check temps I quit my hauling job. Obviously going with synthetics will make a change but how much I don't know.

carl48

no on using both. there is not enough room on the passenger side because of the exhaust, you might be able to stack the transcool on top of the fast cool on the driver side. matt we run a fleet of dodges towing very heavy, I live in the mountains and it gets cold in the winter, we do all of our mechanic work. we see the actual parts that wear in the nv5600 the sae50 is to thick for easy shifting starting off in the winter, that is why the blend. a lot of research went into making sure the additive package of both oils used the same chemicals. with you living in warmer area you may not need the royal purple, just make sure that you fill the transmission up until it runs out the plug and then add at least two extra quarts. there is a ball like thing on the end of the shifter that you can not buy separate from the shifter and does not come in any kit and dodge charges about $350 for the complete shifter. once we moved to the better oil and over filled we have never had another problem with another 5600.

Matt S

Carl48 you were right about not getting them to fit on top of one another. I've changed from the fast coolers to the trans cooler. I had to move the 5" exhaust pipe to get the passenger side on. It was very tight.

I'll be towing again this weekend. I'll see if it makes any difference.

carl48

we cut a little of the fins off and added a heat shield to keep the exhaust temp from heating it.

Matt S

Carl48 - what did you use for a heat shield? I noticed no difference going from the fast cooler to the trans-cool. I figured it would be a bit of a difference. I was hoping the the trans-cool would reduce the heat after some build up on a climb but I didn't see that.

carl48

I have used different things on each truck, just what I grab first. I have exhaust wrap and usually layer it first then I found some material that has foil on one side and high temp insulation on the other, I use hose clamps to secure it to the pipe. cant find pix of nv5600 but here is a g56