How long to heat up a rear diff while driving?

irv

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2,186
Location
Oshawa, Ont. Canada
I plan on finally getting around to changing my rear, and possibly the front, diff fluids so I am curious how long of a drive is needed to heat/warm up the diff fluid enough for a proper drain? Because my Ram has a drain plug I don't plan on removing the cover but I do want the fluid warm/hot first before draining. 3 Ltrs of Pennzoil 75-140 gear oil has been purchased along with some factory LS friction modifier. Thanks in advance. cheers
 
Messages
1,744
Location
Danville, Indiana
Another thing you can do is open it up and just let it drain for a long time. I've let them drain for an hour or two while almost cold and they drain as well as they do when draining for a 10-20 minutes when hot. It is just another option, especially if not near a road where you can really sustain any significant speed.
 
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409
Location
Tacoma, WA, USA
Originally Posted by IndyFan
Another thing you can do is open it up and just let it drain for a long time. I've let them drain for an hour or two while almost cold and they drain as well as they do when draining for a 10-20 minutes when hot. It is just another option, especially if not near a road where you can really sustain any significant speed.
Yep, gonna let my Dana 70 cold drain for a couple hours since the cover has to come off. It's tight under a motorhome so I don't want to "boiling oil" myself.
 
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4,292
Location
N.C.
I drove my truck 5 miles last week on 2 lane rural roads and had my father/son shop pull the cover for the drain. By the time they cleaned off the old gasket and cleaned the cover and magnet in the parts washer, about 30 minutes, the diff had completely drained and had stopped dripping. It was 90 degrees, so outside temps will be a factor.
 

irv

Thread starter
Messages
2,186
Location
Oshawa, Ont. Canada
Thanks guys. cheers Since I don't plan on removing the cover and spraying the internals down with brake clean, I figured a spirited drive would get everything, or almost everything, suspended so that when I drain the diff the majority of crud/wear metals would also come out. I will more than likely let it drain for a good while then add what I can after that due to the slope of my driveway. I will need to park at the end of the driveway on level ground to add the rest. Previous years I have always removed the diff cover (had to) but since this one has a drain, I want to make sure I get as much of the crap out as possible. I appreciate the info. cheers
 
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36,112
Location
ME
So are you going to drain it with the truck angled so you can get more out, clean it, put the gasket and cover on, refill, then level for a final top off? Sounds pleasantly OCD. cheers
 

irv

Thread starter
Messages
2,186
Location
Oshawa, Ont. Canada
Originally Posted by Rand
sounds like a good plan. If you've been changing it that often shouldnt be too horrible.
This will be it's first. The truck, a 13 Ram 4x4, has 72,000 kms on it so I figure it is time. I normally don't wait this long but knowing some never change it for the life of the vehicle, I wasn't too worried about it. As previously stated, I "will not" be removing the diff cover, just the drain plug. My driveway is sloped somewhat so when it comes to refilling it after it has all drained out, I will need to park it at the end of the drive/roadway where it is level in order to get the correct/full amount back in. Thanks for the info guys. I thought it would have taken much longer than what was suggested to get the diff warm/hot. cheers

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