NV4500 and 50 SAE GL-4 Synthetic Trans Fluid

[AH64ID]

I just did a 45 mile drive on the interstate at 75-77 mph in 105-108° weather. My trans was 200° on the PTO cover with a laser thermometer. 

 

Ambient temp may have played a roll :-) 

[KATOOM]

I kinda remember a certain member stating not to long ago that running in any gear other than 1:1 would generate heat.....

[Mopar1973Man]

Just now, KATOOM said:

I kinda remember a certain member stating not to long ago that running in any gear other than 1:1 would generate heat.....

 

That does hold true. Any gear other that direct 1:1 does produce heat either in reduction or overdrive. Overdrive gear does produce the most because of the constant high power (HP/TQ) against it. Where I think that even lower gears do produce some heat but not like overdrive at high speeds like 65 MPH and up. Like with my pass example of towing up hill again laying more power against the gears towing up hill with a lack of cooling wind. The lower gears I would say produce heat because of lack of cooling and typical driving launching from light to light you laying quite a bit of power to the lower gears towing but lacking in the wind to provide good cooling of the transmission. Once the transmission is heated up it takes several miles of 4th gear running at 55 MPH to bring it down. So city driving while towing will produce transmission temps solely for the reason of radiant heat from the exhaust and the lack of cooling wind.

 

To be able to drive in direct gear and be towing 8,000 pound RV and barely make 140-145*F is really good. I was shocked on how long it took for the transmission to even heat up.

 

 

[Mopar1973Man]

A bit of information to add... Towing a 8k pound RV in 4th gear (Direct 1:1) up 7 mile 7% grade in 4th is MUCH COOLER than towing the same RV up the same grade in 3rd which actually tripped off my 220*F warning light and rose to 225*F. Where the 4th gear (1:1 direct) transmission temperatures stay about 180-190*F. 

 

I'll have to say KATOOM is absolutely correct. Direct 1:1 ratio is the most coolest gear to run. 

 

[KATOOM]

Those sound like realistic numbers.....  How hot was the outside temperatures during your climb?

[AH64ID]

I'm guessing whitebird?

 

What speeds in each gear?

[Mopar1973Man]

8 hours ago, KATOOM said:

Those sound like realistic numbers.....  How hot was the outside temperatures during your climb?

 

 

108*F outside. 

 

8 hours ago, AH64ID said:

What speeds in each gear?

 

 

 

3rd Gear at 35 MPH and 2,200 RPMs

 

4th gear at 55 MPH at 2,100 RPMs

Edited July 29, 2016 by Mopar1973Man

[abner99]

What were your egts like?

Edited July 31, 2016 by abner99

[Mopar1973Man]

34 minutes ago, abner99 said:

What were your egts like?

 

In 3rd its like 900-1000*F.

 

In 4th its like 1,100*F-1,200*F.

[abner99]

Whoa that's kinda up there ain't it? You wouldn't think the tranny would run cooler if forth with 1200 exhaust 

[Mopar1973Man]

Again... Like I found out the exhaust isn't the problem as long as the vehicle is moving at highway speeds. Radiant heat is blown off easily. It's when you slow down there is no wind to carry the heat away. I seen the same thing on climbing forestry road and towing my trailer also it even more evident at slower speeds even though AH64ID says it taking less torque to more might be true but there is way less air to cool the transmission. Speed is key to maintaining temperature balance. Also 225*F is nothing for temperature the Mobil 50 SAE is rated to around 280*F (but I don't want to go that high myself) and in the case of this run I was only 1 mile from the top and knew I'd make it. Just as I drop over the other side it would cool down.

 

Even with my daily work travels here in the canyon, I'm abusing it a bit by leaving the truck idle. Now here is some other info. If I have 100-110*F outside temp, leave the truck idle with air conditioning on it will run the transmission temp to 160*F just idling.  Then after I'm done with a job and hop into my chilled cab drive to another job or home typically the empty truck transmission temperature is still right around 140*F even after idling 160*F. Again I'm still without any coolers or mods on the transmission. 

Edited July 31, 2016 by Mopar1973Man

[AH64ID]

That's fairly surprising... but based on what I saw with ECT's and a operational fan this past weekend I buy that it has a lot to do with cooling ability. 

 

There are many different charts but the power requirement at 55 is often as much as double as 35. Throw in the benefit of gearing and the engine is just barely working at 35 compared to 55 so the EGT's aren't surprising in the least... If the wheel torque requirement at 35 is 1,000 it could be 2,000 at 55, but with gearing the engine torque would be 585 vs 2000!!! Those are arbitrary numbers for example. The actual wheel torque required was much less. 

 

Direct gear is going to be the coolest gearing based on torque reduction/increase wise but I really didn't expect that much of a delta in temperatures!!! The amount of torque going thru the gearbox still has to have some effect, thou in direct the gears are just spinning without any torque between the main and coutershaft. 

[abner99]

33 minutes ago, AH64ID said:

That's fairly surprising... but based on what I saw with ECT's and a operational fan this past weekend I buy that it has a lot to do with cooling ability. 

 

There are many different charts but the power requirement at 55 is often as much as double as 35. Throw in the benefit of gearing and the engine is just barely working at 35 compared to 55 so the EGT's aren't surprising in the least... If the wheel torque requirement at 35 is 1,000 it could be 2,000 at 55, but with gearing the engine torque would be 585 vs 2000!!! Those are arbitrary numbers for example. The actual wheel torque required was much less. 

 

Direct gear is going to be the coolest gearing based on torque reduction/increase wise but I really didn't expect that much of a delta in temperatures!!! The amount of torque going thru the gearbox still has to have some effect, thou in direct the gears are just spinning without any torque between the main and coutershaft. 

Now I agree with that the ability to cool the ability to get rid of heat. Shed it essentially. As for the other I'm 50/50 but that's just me.  

Edited August 1, 2016 by abner99

[KATOOM]

I just got back from a weekend camping trip.  We've been going through a nice little heat spell the past week so we tried to get away from the warmth.

 

Packed up, we left on Friday at 6 pm hoping would be a tad cooler outside.....but it was still 111*.   Everything was HOT!!!!!  AC on full blast, he headed up the roasting highway.  I do NOT enjoy towing in that kinda of heat, especially since when pulling my 5th wheel I'm grossing around 22k pounds.

 

I live at around 300 feet elevation and we drove 100 miles up the mountain to about 3500 feet.  Got there about 8:30 and thankfully it cooled off to a nice 100*.

 

Lots of gradual pulls throughout the drive with a few steep grades here and there just to keep the truck from ever cooling off.  The engine fan NEVER shut off, roaring constantly the entire time at about 2200-2300 RPM.  ECT's were comfortable but consistently swung between 205*-215* depending on the grade.  The transmission temperatures remained stable at 175* and climbed to about 185* on a couple steeper 3rd gear pulls.  The differential temperatures remained at about 210* for the duration.

[AH64ID]

Interesting... Looks like the SAE 50 runs quite a bit hotter under load. 

[Mopar1973Man]

48 minutes ago, AH64ID said:

Interesting... Looks like the SAE 50 runs quite a bit hotter under load. 

 

Can't use his data to compare. KATOOM is running insulated exhaust pipe. I'm also pretty sure using fast coolers as well. So it not a true apple to apple comparison. I'm truly stock no coolers and no pipe insulation.

[AH64ID]

I realize that, but the delta of his norm to his peak on the same trip with more weight and higher ambient temps tells me that the SAE 50 runs hotter. 

 

It's not a 100% direct comparison by it cannot be ignored either. 

Edited August 2, 2016 by AH64ID

[KATOOM]

I agree that this is definitely not a direct comparison because I do know that the Fast Coolers do play a part and I know for fact that the blanketed exhaust does something as well.  But the information is still a guideline when understanding that my gross was much heavier (almost double the trailer weight) and the ambient temperatures were about the same.

 

It'd sure be nice if someone else running 50 weight had a temperature gauge too so we could collect more data.

[Mopar1973Man]

What would be a better comparsion would be to take two trucks and the only difference would be the fluid one with 50 SAE and the other Castrol Syntorq. No other mods. Then both truck towing the same amount of weight up the same hill together at the same time. Then you'd have some data. There is all kinds of variables not considered in AH64ID comment. Winds, tire differences, loads (weight), tire inflation, etc. All these thing can impact the outcome of the transmission temperature. I bet that if I go back to driving the way I normally do I never reach that 225*F mark again. Just did the 3rd gear climb to prove that reduced ratio gearing and lower road speeds does produce a lot of heat in the transmission and that was the only purpose of the post. 

[AH64ID]

You can pick apart all the differences but the bottom line is a truck with more weight, more drag, and higher ambient temps had a smaller delta in 4th to 3rd gear. That's quantifiable.