DT RAM 1500 5.7L towing oil temps

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Lots of miles on the ZF 8HP's out there, it isn't a box that's failing before 100K, probably the best trans on the market actually.
Good to hear because I have one in the wife's JEEP GC with 128k mile and my RAM limited has 97k miles. I feel terrible that I have not changed the fluid in either one yet. The Jeep only sees occasional off road and the RAM tows a car hauler occasionally so I think I am ok. I really should probably do a fluid change.
 
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While not a DT, my DS runs about the same. Hottest I’ve ever seen the oil was 230F but I was driving in a… spirited manner.

I have found Tow/Haul mode seems to help my fuel economy, maybe because it can stay in MDS longer while on hills and stuff and it seems to require less throttle cruising on flat ground in 7th vs 8th? Whatever the reason, it’s definitely more pleasant to drive in tow/haul.
FB45515F-8FD7-4231-84F9-066C74926FD9.jpeg
 

4WD

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Watching Jeep temps in deep sand yesterday … they were all over the place (especially coolant) but oil temp did not exceed 219F … if I would find a hard spot and idle a few minutes … it all cooled to 200-205F …
Oil = 215F on the highway going home at less load and lots of airflow you don’t have in sand …
Was especially nice to see the 850RE seldom go above 200F even in 4-High … 😎
 
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Hope that's true but plenty of modern transmissions are failing before 100K these days.
Yes but how many of those failures were from towing? These truck units seem (vastly) different than their car counterparts.
 

ls1mike

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Ah, got it Not a GM guy.

The 1500s definitely have thermostats. I was so impressed with the truck I started looking at them. Was really surprised when I saw they had a thermostat. A lot of people seem to remove them.
Yeah they even make a kit, they run too hot. I am not sure the reason for the thermostat a the 6L90E doesn't have one and they do fine.
 
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Had my dad snap this shot of the cluster while I was towing the boat up to the cottage. Most of the trip was spent in 7th (tow/haul limits 8th to above 100Km/h) with it being in 8th once we got onto highway 11.

This is not a super heavy load, probably around 4,500lbs combined? A fair bit lighter than our Four Winns, which isn't quite ready to go up to the lake yet.

This truck has the 3.92 rear axle ratio with tow package (trailer brake controller...etc) and oil cooler.

I also had him snap a pic of oil pressure. This is M1 EP 0w-20. Relief pressure on the pump is 75psi, a downshift to 6th to accelerate put it up around 3K and 55psi.

For those not using metric, 108C is 226F, which is quite reasonable. As you can see, ambient temp is quite warm (33C/91.5F) which likely explains the higher observed temp than I saw in the fall when it was much cooler. OE thermostat opening temp is 195F IIRC.

View attachment 59718
View attachment 59719
Did you happen to look at the coolant temperature?

My Ram 2500 with the 6.4 runs 210-215F coolant and oil temperature most of the time, even when unloaded. I have not noted the transmission temperature but will the next time I tow something.
 
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The general consensus seems to be the newer transmissions, including some Ford’s, run at over 200 F on a routine bases. Here is an excerpt from one auto writer regarding Ford. That said, there is no info on the expected life of the transmission.

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OVERKILL

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Did you happen to look at the coolant temperature?

My Ram 2500 with the 6.4 runs 210-215F coolant and oil temperature most of the time, even when unloaded. I have not noted the transmission temperature but will the next time I tow something.

I did, but forget what the temp was now. I'll track it again when we tow the Four Winns up.
 

JTK

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You wouldn't think these hemis would heat the oil to the degree they do given they hold ~7 qts and have an oil cooler. I know the hemi in my 2019 Ram 1500 classic will hit 212F+ on an 85deg day no problem. Coolant and ATF run much cooler. My ZF8s ATF will still hover in the 185degF range with 200+ engine oil temps.
 
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You wouldn't think these hemis would heat the oil to the degree they do given they hold ~7 qts and have an oil cooler. I know the hemi in my 2019 Ram 1500 classic will hit 212F+ on an 85deg day no problem. Coolant and ATF run much cooler. My ZF8s ATF will still hover in the 185degF range with 200+ engine oil temps.
Mine has gotten up to 240F during uphill drives on 17 in AZ.
 
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My old 2011 outdoorsman, 3.92, with apparently a tow package towed decently. When I hauled round bales, I would have it north of 10,000 pounds and ran hard. I could get thr coolant to about 107c, oil at 114c after a decent uphill pull. Once I got the 545RFE to just over 106c when towing about 10k at highway speeds against a terrible head wind. It was in and out of lockup real bad.

Truck kept ticking for years doing this and asked for more. When I changed the atf, it was still rosey red and smelled just fine.

I was quite worried about the temperatures but I guess the truck didn't.
 
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JTK

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Snapped a pic of my dash just a bit ago. This was after several ~20 mile runs in/out of town. Lots of hills, a bunch of stops on an 80degF super humid day with the A/C on. I guess my engine oil temp runs hotter than I thought. This is on Supertech synthetic 5w30, a bottle of LiquiMoly MoS2 and a $2 Champ filter. I do 5000mi OCIs. Usually a tad sooner.

CuRAiQ6l.jpg
 
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In the racing world, the 0W oils work well to increase HP. However, the trick to making them work has been to actively manage the oil temp around 100c. Afterall, it's an oil's viscosity that provides the majority of the protection. While 225 degrees is well within the norm, it's about the limit of what most racers using 0W oils would like to see under high loads.
 

OVERKILL

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In the racing world, the 0W oils work well to increase HP. However, the trick to making them work has been to actively manage the oil temp around 100c. Afterall, it's an oil's viscosity that provides the majority of the protection. While 225 degrees is well within the norm, it's about the limit of what most racers using 0W oils would like to see under high loads.

Any idea of what the oil temps were on the 24hr cars at LeMans and Sebring where M1 0w-40 seems to be the oil of choice?
 

OVERKILL

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Just another data point, this is the truck with about 15 minutes of driving on it, no trailer:
73AE5B8C-432C-4687-8356-37E0A96CDF2E_1_105_c.jpeg


Trans definitely takes longer to heat-up than the oil, but then there's a LOT more trans fluid. For those not doing the metric thing, that's a trans temp of 190F with oil and coolant at ~218F.
 
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Just another data point, this is the truck with about 15 minutes of driving on it, no trailer:
View attachment 60006

Trans definitely takes longer to heat-up than the oil, but then there's a LOT more trans fluid. For those not doing the metric thing, that's a trans temp of 190F with oil and coolant at ~218F.
I appreciate you converting to Freedom Units for us!
 
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