Syn/Dino blend 50/50 R. Axle change?

[BBDARTZ]

Just wondering if there is any advantage or potential problems with mixing half and half a quart of syn. with a quart of conventional 85-140 for a rear axle oil change on a 86' Dodge W-250 with 50K miles on the odo.. I use it for snow plowing and fire wood hauling on forest trails. I almost never exceed 55mph in this vehicle but it works hard plowing and hauling, about 2k avg. miles/yr.

 

[oggb]

It'd probably be fine.

 

[chubbs1]

I agree it will be fine. I would prefer to use syn myself (due to the cold) but since you drive it so little no harm. What brand(s) are you mixing?

 

[BBDARTZ]

I'll be blending Valvoline High Perf. 85w-140 with Walmart house brand 75w-140 syn.. Normally, I would perfer to use 100% syn., but for this vehicle that gets used so little, it is hard to justify the extra $15.00/Quart. I have most of a quart of syn. left over from another p/u truck I owned and had good results with the Walmart brand even though I definitely maxed out the towing capicity on that truck for many miles. I would never recommend Walmart brand for anything critical and especially not in the motor, but the gear oil has given me good results in the past.

 

[Maritime Storm]

I see no need to use 75W140 in this rear end. This sites founder years ago discovered that synthetic gear oils don't cling very well to differential gears at low speeds, so switching to a synthetic would be worse wear wise than using the conventional oil.