Front and rear diff/transfer drain and fill

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MisterB

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I have a 3/4 ton 4x4. I'm not sure which front and rear end or transfer case I have. After searching, it sounds like I need to pull the covers, take pictures, post it here and then we can identify which I have? As for the transfer case, I should be able to take a Pic of it and we can figure that out too?

I'd like to figure out which gear oil I need, and how much. Is it all the same, other than some need a Limited slip additive? It sounds like some transfer cases use transmission fluid or motor oil, or it could be gear oil depending on which one I have.

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Vbb199

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I have a 3/4 ton 4x4. I'm not sure which front and rear end or transfer case I have. After searching, it sounds like I need to pull the covers, take pictures, post it here and then we can identify which I have? As for the transfer case, I should be able to take a Pic of it and we can figure that out too?

I'd like to figure out which gear oil I need, and how much. Is it all the same, other than some need a Limited slip additive? It sounds like some transfer cases use transmission fluid or motor oil, or it could be gear oil depending on which one I have.

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14b sf rear end probably.
That'd be my guess
Front would be d44 or standard corporate 10 bolt

T case would be 203 or 205.
How many positions are on the 4x4 lever?

205 would be 2hi, 4hi, neutral 4lo (if I remember right)

203 would be 4hi neutral 4 lo.

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Vbb199

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D44 or Dana 44 BTW.

Dana axles (I think)
Can always be identified by the 2 cast holes in on the left and right of the diff cover.
For the seperator device for installing the carrier.

Also, a tag will be somewhere on the axle, usually around the cover.
And somewhere on the axle tube (if it's dana)
There are stamped numbers which is called a BOM number.
Look for it.





14 b sf or 14 bolt semi float will have quite literally 14 bolts on the diff cover.

14 bolt semi float and 14 bolt Full float are the 2 most common axles in 3/4 and 1 ton squares, some would have a dana 70 (don't hold me to that)

Or a dana 60.

If I'm not mistaken, I thought the older early squares might have a dana 44 rear end if they were 3/4 or 1 ton as well... Someone with more extensive knowledge might be able to shed light on the subject.

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Vbb199

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Also, RPO codes will go a long way if the sticker is still there [emoji28]

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legopnuematic

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MisterB

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Also, RPO codes will go a long way if the sticker is still there [emoji28]

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Only sticker in the glove box is camper loading info with the vin

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MisterB

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14b sf rear end probably.
That'd be my guess
Front would be d44 or standard corporate 10 bolt

T case would be 203 or 205.
How many positions are on the 4x4 lever?

205 would be 2hi, 4hi, neutral 4lo (if I remember right)

203 would be 4hi neutral 4 lo.

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75gmck25

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That shifter is for the NP205 gear driven part-time transfer case, which is a very strong case.

1980 is a "sweet spot" where they quit using the NP203 chain driven full time transfer case on 1/2 ton and 3/4 trucks, but had not switched to the chain-driven NP208 part-time cases. The NP205 is a very reliable transfer case. IIRC it uses 80w90 gear oil, but I know some guys have also used ATF. The NP203 is the case that uses 10w30.

The 14 bolt FF is a great axle, but be prepared for extra time and cost when you do the rear brakes. My 8200 GVW Camper Special has the large 13" drums (expensive), and on a FF you have to pull the axle before you can remove the drums and replace brake pads.

Your rear axle may also have the G80 gov-lock differential, which has a checkered reputation. The locking part is engaged by centrifugal force when speed is different between the two axles. If you spin it up relatively slowly (like a farm truck stuck in the mud!) it engages and works fine, but if someone does burn-outs on pavement it may engage and lock abruptly and break something internally in the locking mechanism.

Bruce
 

MisterB

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That shifter is for the NP205 gear driven part-time transfer case, which is a very strong case.

1980 is a "sweet spot" where they quit using the NP203 chain driven full time transfer case on 1/2 ton and 3/4 trucks, but had not switched to the chain-driven NP208 part-time cases. The NP205 is a very reliable transfer case. IIRC it uses 80w90 gear oil, but I know some guys have also used ATF. The NP203 is the case that uses 10w30.

The 14 bolt FF is a great axle, but be prepared for extra time and cost when you do the rear brakes. My 8200 GVW Camper Special has the large 13" drums (expensive), and on a FF you have to pull the axle before you can remove the drums and replace brake pads.

Your rear axle may also have the G80 gov-lock differential, which has a checkered reputation. The locking part is engaged by centrifugal force when speed is different between the two axles. If you spin it up relatively slowly (like a farm truck stuck in the mud!) it engages and works fine, but if someone does burn-outs on pavement it may engage and lock abruptly and break something internally in the locking mechanism.

Bruce
Good to know. Thanks. No burnouts for me

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Vbb199

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I'll speak for the gov-bomb.
I've grenaded severall, behind a stock 350, behind a 6.2 diesel, and behind a "hot" 4.3

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Vbb199

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I'll speak for the gov-bomb.
I've grenaded severall, behind a stock 350, behind a 6.2 diesel, and behind a "hot" 4.3

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Actually the 4.3 Has been thru 2 of them, and rear end number 3 is on its way out [emoji12]

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Rick Dobbins

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If you have an 8 lug wheel and there are 10 bolts on the differential cover, you have a Dana. If you have a 6 or 8 lug wheel and there are 14 bolts on the differential cover, it’s a 14 Bolt. If you have 8 lugs on the wheel and 12 bolts on the differential cover, you have a Sterling 10.25.

As far as oil, I use 75W-140. Go on YouTube and you'll find a video of a rear under power with a plastic diff cover installed so you can watch what happens to the oil. You won't believe it! It's very violent and tends to 'wrap' around the ring gear, thus starving the bearings.

The 75W-140 really helps to curb that and your rear end will last allot longer.
 
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MisterB

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If you have an 8 lug wheel and there are 10 bolts on the differential cover, you have a Dana. If you have a 6 or 8 lug wheel and there are 14 bolts on the differential cover, it’s a 14 Bolt. If you have 8 lugs on the wheel and 12 bolts on the differential cover, you have a Sterling 10.25.

As far as oil, I use 75W-140. Go on YouTube and you'll find a video of a rear under power with a plastic diff cover installed so you can watch what happens to the oil. You won't believe it! It's very violent and tends to 'wrap' around the ring gear, thus starving the bearings.

The 75W-140 really helps to curb that and your rear end will last allot longer.
Here is my rear diff and rear wheel. Assuming that means I have a "14 bolt"? Does that mean I should use that weight gear oil you recommended?
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