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I've looked through some of the different threads and am I right in concluding and 50 engine oil will work in the tranfer and trans? I couldn't find 50 gear oil any place today except at Kenworth service center. They would only sell me a 5 gal pail for $150. I found Valvoline 50 motor oil at NAPA.

Cav Trooper

It would seem logical that SAE 50 gear oil and SAE 50 engine lubricating oil are the same, but they're not. They have the same viscosity, but different additives.

Will the motor oil work in a trans or t-case? Yes. It will lubricate the gears just fine.

Will it hold up over the long haul? I dont know.

Would I use it? Probably not. I'd stay with the manufacturer's recommended product.

Why? 'Cuz the engineers who designed it know more about that stuff than I do.

Ok, I thought as much. Now, where do I find 50wt gears oil without buying a 100 yr. supply? Hoping to find it at a local merchant.

Thanks,

Cav Trooper

50 weight trans lube is the standard for heavy trucks these days, this is why you found it at the KW dealer The local parts house is not a good source. You need to go to an oil supplier. One who deals in selling oil and lubricants only, such as a Chevron jobber, etc for example. They will have what you need. The spec for the Spicer 5-speeds we use actually calls for 30, 40, or 50 weight heavy duty engine oil, depending on the ambient temps in your area. 30 being for cold, 40 and 50 being for warmer temps.

In relation to the manufacturer's recommendations for oil; in those days it was 30 weight in the engine and 90 weight in the gear boxes. Think about it, that was virtually all there was in those days. Oils and lubricants have come a long way since that time. Long story short, there are better choices than what the book that was dated 1951 suggested. Take advantage of far better lubricants that are available today, you gears will love you for it. Some grumble that they changed to up to date oils and it leaked out; well I learned a long time ago that oil will not stay in any component unless you repair any leaking issues prior to pouring it in, common sense applies here.

All of the seals have been replaced, however, they all leak. Can you give me an idea of what you seal kit runs?

Cav Trooper
galaske@3z.net

Cav Trooper wrote:All of the seals have been replaced, however, they all leak. Can you give me an idea of what you seal kit runs?

Cav Trooper
galaske@3z.net

Which seals are leaking? If you can supply this information in detail, I can offer some suggestions for you.

At the moment, I need to clean all of the oil off the whole drive line to see which ones. It looks like the trans output, transfer case and front and rear diff. There might be one or two that are leaking around the pig bolts on the diffs. Again I need to clean everything up to get a better idea. All of the oil is fresh.

Cav Trooper

MSeriesRebuild wrote:50 weight trans lube is the standard for heavy trucks these days, this is why you found it at the KW dealer The local parts house is not a good source. You need to go to an oil supplier. One who deals in selling oil and lubricants only, such as a Chevron jobber, etc for example. They will have what you need. The spec for the Spicer 5-speeds we use actually calls for 30, 40, or 50 weight heavy duty engine oil, depending on the ambient temps in your area. 30 being for cold, 40 and 50 being for warmer temps.

In relation to the manufacturer's recommendations for oil; in those days it was 30 weight in the engine and 90 weight in the gear boxes. Think about it, that was virtually all there was in those days. Oils and lubricants have come a long way since that time. Long story short, there are better choices than what the book that was dated 1951 suggested. Take advantage Some grumble that they changed to up to date oils and it leaked out; well I learned a long time ago that oil will not stay in any component unless you repair any leaking issues prior to pouring it in, common sense applies here.

H



Guess I missed this information. Just 2 weeks ago I HAD a dry transfer case. I finally got around to changing the gear oil and on the first drive, the 2 seals for the shift linkage started leaking. So I changed both and now the front axle pinion is now dripping