Transfer Case

[Mike Sammons]

I have the all Time 4x4 in mine, I want to change the drive line oils. Front and rear diff, Trans, And Transfer Case. Was wondering what kind of oil I need the the transfers Case and Trans. I assume 90weight in the Front and rear differential.

 

[1987 GMC Jimmy]

80w90 in the diffs., SAE 30 motor oil in the t-case, and Dexron III or equivalent in the transmission. Some people like to use Type F, but I’m fine with the Dexron. This is just what I use and what I remember the NP203 uses.

 

[Snoots]

X2

Don't forget the additive if you have a posi rear axle.

 

[1987 GMC Jimmy]

X2

Don't forget the additive if you have a posi rear axle.

What do you use for this?

 

[rpcraft]

I don't think the NP203 used trans fluid that was shared with the automatic transmissions but rather something in the range of motor oil, not gear oil though. I'm not 100 % sure on the mix though and can't really verify that.

 

[HotRodPC]

What do you use for this?

Something like this. It's usually used in units that have clutches in them. Usually like a Limited Slip Differential. I don't think the Gov LoK requires it IIRC. Gov Lok is considered a locking diff, not a Limited Slip Diff, although it does slip just a bit before the cam locks and grabs the other wheel. But it's all mechanical, no clutches.

https://transpartswarehouse.com/m46...QZ4CzKp3CrbaPU-O1kSgNzM0qUAeRFvoaAr6LEALw_wcB

 

[idahovette]

Lubeguard makes an additive for posi units

 

[idahovette]

I don't think the NP203 used trans fluid that was shared with the automatic transmissions but rather something in the range of motor oil, not gear oil though. I'm not 100 % sure on the mix though and can't really verify that.

See Jesse's post #2. All 203's I have seen use 30w motor oil

 

[HotRodPC]

Lubeguard makes an additive for posi units

So does Lucas and many others too. It's not very uncommon. Of course stealerships and owners manuals will list the GM Part # and claim there's is the only one but that's just not true. I'd first ID which LSD or Posi unit you have, Like an Auburn, Eaton, whatever the case may be along with the model # or name and then go to that manufactures website to see what spec of additive they call for.

 

[1987 GMC Jimmy]

Something like this. It's usually used in units that have clutches in them. Usually like a Limited Slip Differential. I don't think the Gov LoK requires it IIRC. Gov Lok is considered a locking diff, not a Limited Slip Diff, although it does slip just a bit before the cam locks and grabs the other wheel. But it's all mechanical, no clutches.

https://transpartswarehouse.com/m46...QZ4CzKp3CrbaPU-O1kSgNzM0qUAeRFvoaAr6LEALw_wcB

I didn’t think I needed anything special in the ole Gov-Bomb, but I was just making sure. I’m about to have it rebuilt in a week so I wanted to make sure it had what it needed.

 

[HotRodPC]

I didn’t think I needed anything special in the ole Gov-Bomb, but I was just making sure. I’m about to have it rebuilt in a week so I wanted to make sure it had what it needed.

You're going to get it rebuilt with the gov bomb or you gonna get it rebuilt with a different carrier?

 

[1987 GMC Jimmy]

You're going to get it rebuilt with the gov bomb or you gonna get it rebuilt with a different carrier?

My pinion bearing, ring, and pinion are shot so I’m just doing a master rebuild kit and keeping the Gov Bomb. I don’t go that hard on it so I figured it’d be alright.

 

[Rusty Nail]

GL-5 doesn't require a separate additive ppl...

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