Front/rear Axle Lube

[hex0rz]

I cant speak for or against synthetic, but when you open it up, its all going to drain other than what sticks to the gears. Make sure you have a good size drain pan in case the cover pops off quickly.

 

Take off all of the bolts except a few at the top. Loosen them a little and pry the bottom. This will contain the fluid to drain at the bottom and limit flow.

[Mopar1973Man]

I honestly cant think of one drawback to synthetic diff oil including cost when looking at the big picture. Some synthetic oil manufacturers recomend up to 100k mile service intervals compared to 30k intervals of the traditional mineral oils. They also offer more protection at both ends of the temperature range and will not break down as quickly (hence the extended intervals) Most if not all passenger vehicles these days factory fill with synthetic and is considered a "lifetime fill", meaning the oil is fine until service of the gear sets or seal replacement is needed (or contamination is suspected). Essentially all of the service intervals in the service manuals of our trucks are based off of the oils capabilities at the time. Oils are much more advanced these days and there is really no reason to not take advantage of them and enjoy the added protection and extended service intervals.

 

From the end user perspective its a bit different. Most get the idea its synthetic I never have to inspect the fluid at all for 100k miles or even worry about it. This is one of the common down falls. So now the end user changes the differentials fluid tops it off good to go 100k. As long as its not leaking out the owner is happy. Opps... Bad thinking. So many times I've open up differentials around here found them overly contaminated in form or other. Just because its synthetic means you still have to do the inspections of the fluid level and color and check for contamination of the fluid.

 

[Wild and Free]

If you are in extreme cold you will see a huge difference. A guy I know had the same truck as me (F-150 4wd 4spd) and was parked on a slight hill. I parked next to him and we both left at the same time a couple of hours later. I pushed the clutch in and my truck did not move. His truck rolled just as soon as he pushed the clutch in. He had synthetic through out and I didn't. The cold flow capabilities and higher heat tolerances make synthetic better in my book.

This is what got me started on synthetics about 15+ years ago. It all started with gear lubes for me and went from there.

On my 95 Dodge 1500 in the winter in sub zero temps parked on an incline, when I put it in reverse / auto and had to accel to upwards of 1200+ rpms to get it to roll because the gear lubes were that thick it felt like the park brake was on, let off the throttle and it stopped again, got me to thinking and I have not looked back.

You take a standard 80-90 and a syn 80-90 and pull them hard for 50K miles with the Dino you will have to scrape the tar out of your diff cavity by then. If You think trannies get hot what do you think your working diff temps are with the same load and half the oil as your manual tranny?

For the guy who uses it for a DD grocery getter and rarely works it if ever then it doesn't matter much, you wind up with what is in mikes pics above, condensation build up from lack of getting up to a decent temp to evaporate the condensation.

Edited January 13, 2014 by Wild and Free

[diesel4life]

From the end user perspective its a bit different. Most get the idea its synthetic I never have to inspect the fluid at all for 100k miles or even worry about it. This is one of the common down falls. So now the end user changes the differentials fluid tops it off good to go 100k. As long as its not leaking out the owner is happy. Opps... Bad thinking. So many times I've open up differentials around here found them overly contaminated in form or other. Just because its synthetic means you still have to do the inspections of the fluid level and color and check for contamination of the fluid.

you are right, it does take a bit of common sense when dealing with extended drain intervals, but at the same time it really is no different then running traditional mineral oils. Whether your changing at 30k or 60k (I don't know that I would be comfortable going 100k without some type of analysis considering all the towing I do and the torque of a diesel engine and for the cost it's probably better to just change it), you still have to periodically check for contamination, abnormal wear materials, and level. Even if you went 60k thats twice the interval of dino, and the cost is not double.

[Mopar1973Man]

You take a standard 80-90 and a syn 80-90 and pull them hard for 50K miles with the Dino you will have to scrape the tar out of your diff cavity by then. If You think trannies get hot what do you think your working diff temps are with the same load and half the oil as your manual tranny?

 

Manual NV4500 hold 1 gallon and so does my rear diff. Yes I've extended my interval sometimes up wards to 40-45k miles if the fluid was not dark yet. Like on the 1996 I just extended them as well the fluid is still honey colored when I last sampled it. (Mobil Petroleum 80w-90 GL-5).

 

I do tow but not right at GCWR of 20,000 pounds but 16,000 to 17,000 is pretty dang good pull when you start hauling up and down grade of 16% in the mountains here. My intervals are based between color, contamination, and mileage. If color and contamination but are good then push the mileage up another 5k miles. If the color or contamination is getting poor skip the mileage part and dump it now and change.

[joecool911]

Wow, gear oil is expensive! List price was $40 per gallon. Have a buddy that gets a good discount at Napa. Got 8 quarts of Napa brand 80/85/90 and a tube of RTV for $42. Opting for more frequent fluid changes with regular old petroleum based fluid. The quarts are in the tall bottles with spout. Won't have to buy a pump to get the fluid into the axles like you would in a gallon container. Plus it was cheaper.

Edited January 13, 2014 by joecool911

[joecool911]

I've got all my stuff, but it seems too cold for reasonable dry time of RTV. 35* day and 25* night. Old oil slow to drain and cold pumpkin for sealer to cure. I know I could drive it and warm em up, but still seems too cold out. Will the front axle get warmed up without engaging 4 wheel drive?

Edited January 19, 2014 by joecool911

[Mopar1973Man]

Might want to check on 5 gallon bucket prices typically are better.

[GSP7]

Use this where there is no gasket used

Permatex® Ultra Grey® Rigid High-Torque RTV Silicone Gasket Maker - See more at: http://www.permatex.com/products-2/product-categories/gasketing/gasket-makers/permatex-ultra-grey-rigid-high-torque-rtv-silicone-gasket-maker-82194-detail#sthash.sABSAhqS.dpuf

http://www.permatex.com/products-2/product-categories/gasketing/gasket-makers/permatex-ultra-grey-rigid-high-torque-rtv-silicone-gasket-maker-82194-detail

Edited January 19, 2014 by GSP7

[diesel4life]

Do you have a torpedo heater? Or take the cover inside to warm it up, put the silicone on it, and take it out and install it.

Or, for roughly the price of a tube of silicone, you can go buy a gasket and be done with it. IIRC the front and rear cost less than $15.