Rear Differential Temperatures

[mrclean426]

if you can hold your hand on it for 5 sec without 3rd degree burns it is not at 200 degrees

 

[gsfitzsr]

I wrecked the rear end in my 2500 after towing a 12KLB 5th wheel across country. I found some article showing the Mopar fluid had poor film strength. I replaced it with Amsoil fluids in both axles and never looked back. When I upgraded to a 3500 I replaced the axle fluid with Amsoil immediately. Not going through that again.

Use a quality fluid and don't worry about the temperature of the differential case. You could always replace the diff cover with a finned cover.

 

[Bob Horowski]

AGAIN overthinking a non-issue. Did you ever hold your hand to the cover BEFORE you changed the fluid? Just follow the factory recommended fluid fluid specs and be done with it.

 

[ppine]

Owner's manual lays it out.

Dean2,
I must have gotten confused from some ****** on the internet. Sorry.
Temperature is not much of an issue for a rear diff.

 

[Dusty]

Funny, in 2019 I could've ordered a heavy duty towing package for my 1500 that included a 9.5 diff that was connected to the engine cooling system.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 138383 miles.

 

[crazy jerry]

You need at least a 1/2 hour or more,closer to an hour is even better,before it'll be at full operating temp,15 minutes isn't near long enough to get a diff up to temp,especially a heavy duty one,that has a pile of steel to heat.Take it for a good hour long drive and run it up to 70+ mph for a bit,as that's closer to most highway speeds

no it does not take a hour. thats rediculous. summer months the rear runs about 170 empty and it gets there fairly quickly. within 30 miles or so at 75mph

 

[crazy jerry]

actually its already at 170 within 30mi so it likely hits 170 within 10miles. then its able to maintain the 170ish

 

[Wild one]

actually its already at 170 within 30mi so it likely hits 170 within 10miles. then its able to maintain the 170ish

Don't think so,i've measured 180 at 30 miles at 75 mph and 200+ at 150 miles at a steady 90+ mph,on a 90 degree day. Putting 140 into it is "not" gonna hurt the diff,in fact the diff will live longer in 99% of cases with 140 then it will with a 90 weight in it,especially if you work the truck. Some of you guys would jump off a cliff if the owners manual told you to . They only dropped the fluid specs to improve milege,they sure didn't drop them to increase the longevity of the diff

 

[crazy jerry]

Don't think so,i've measured 180 at 30 miles at 75 mph and 200+ at 150 miles at a steady 90+ mph,on a 90 degree day. Putting 140 into it is "not" gonna hurt the diff,in fact the diff will live longer in 99% of cases with 140 then it will with a 90 weight in it,especially if you work the truck. Some of you guys would jump off a cliff if the owners manual told you to . They only dropped the fluid specs to improve milege,they sure didn't drop them to increase the longevity of the diff

this is what i know as fact. summer day, empty truck ,75mph ,80w90 , rear is already at 170 in 30mi.
likely it hit 170 around 10-15mi but i didnt check that as it was irrelant to me.
at constant 75mph it never waivers from 170 even after very long distances.
extra thick iron and steel diff covers vs stock cover make no difference at all in the above temp results.
good day sir

 

[Wild one]

this is what i know as fact. summer day, empty truck ,75mph ,80w90 , rear is already at 170 in 30mi.
likely it hit 170 around 10-15mi but i didnt check that as it was irrelant to me.
at constant 75mph it never waivers from 170 even after very long distances.
extra thick iron and steel diff covers vs stock cover make no difference at all in the above temp results.
good day sir

Wonder why Nascar guys run diff coolers if it never gets above 170 Yea we're gonna have to agree to disagree on this,as i've measured 200+ with roughly 200 pounds of track supplies in the box after 150 miles at a steady 90mph on a 90 degree day.Admittedly there was some hills involved,but nothing i'd call mountains though

 

[crazy jerry]

your lumping nascar differentials into this now ? unbelievable
if your truck is a 1500 then perhaps the diff just gets hotter. i dont know.
the op's 2500 will be around 170ish cruising empty at 75mph. ive already verified it numerous times