4x4 shifting question from a noob

[Giant Rock]

I have a 1990 Suburban with 4x4 shifter on the floor. It's my understanding that to shift into 4L the proper way is to put the truck into Neutral and to coast between 3-5mph, then shift into 4L. That is all well and good for when you know something challenging might be coming up. Out here in the desert 95% of the dirt roads I travel can be driven in 2-wheel drive, it's only the occasional hills and sandy washes that require 4x4. The hills are obvious but the sandy parts aren't always...So the question becomes, what happens if you get stuck in 2-wheel drive and need to shift into 4L but you don't have the ability to coast? This happened once to me when I didn't know what to do with the truck and it made a grinding noise, I was at a loss so I just slammed it through the grind and it worked....not ideal I'm sure but we got unstuck easily. Any advice appreciated.

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[mcarlo86]

You can shift into 4H for situations like that, don't have to use 4L every time you need four wheel drive.

 

[FireTruck1984]

I have a 1990 Suburban with 4x4 shifter on the floor. It's my understanding that to shift into 4L the proper way is to put the truck into Neutral and to coast between 3-5mph, then shift into 4L. That is all well and good for when you know something challenging might be coming up. Out here in the desert 95% of the dirt roads I travel can be driven in 2-wheel drive, it's only the occasional hills and sandy washes that require 4x4. The hills are obvious but the sandy parts aren't always...So the question becomes, what happens if you get stuck in 2-wheel drive and need to shift into 4L but you don't have the ability to coast? This happened once to me when I didn't know what to do with the truck and it made a grinding noise, I was at a loss so I just slammed it through the grind and it worked....not ideal I'm sure but we got unstuck easily. Any advice appreciated.

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It sounds like the situation called for 4H.. you can shift to 4H on the fly up to 25 mph. For 4L you should be at a stop or you will get all that grind you encountered

 

[Giant Rock]

It sounds like the situation called for 4H.. you can shift to 4H on the fly up to 25 mph. For 4L you should be at a stop or you will get all that grind you encountered

Well now I'm really confused. From my research you are supposed to coast in neutral at 3-5mph to shift into 4Lo. And that is what I have been doing and have been getting no grind. It was only when I WAS STOPPED and tried to shift into 4Lo that I got the grind.

 

[Giant Rock]

You can shift into 4H for situations like that, don't have to use 4L every time you need four wheel drive.

But can you shift into 4H when completely stopped?

 

[Vbb199]

4 low is offroad only (or where there's minimal traction) come to a stop. Switch it in, lockout the hubs.

4hi can be engaged while moving at low speeds

Or at a stop. Doesn't matter.

 

[FireTruck1984]

Well now I'm really confused. From my research you are supposed to coast in neutral at 3-5mph to shift into 4Lo. And that is what I have been doing and have been getting no grind. It was only when I WAS STOPPED and tried to shift into 4Lo that I got the grind.

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[Giant Rock]

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[Giant Rock]

Anyone got a pdf of the manual for 88-91 Suburban? Would love to see what that bad boy says about shifting into 4L.

 

[FireTruck1984]

Anyone got a pdf of the manual for 88-91 Suburban? Would love to see what that bad boy says about shifting into 4L.

It’s possible your 1990 calls for a different procedure, but I’ve never heard of that. The transfer case and shifter should be the same..but there is always variables

 

[Vbb199]

90 and 91 in half ton is more than likely a np241. (uses electronic speedo with reluctor ring in the transfer case)


Basically the same as the np208 that's been around... Like, since the early 80's, except the np208 uses a cable.

Edit, I think 3/4 and even in 1 ton may have also used a np241. But I may be mistaken.

 

[Vbb199]

Anyone got a pdf of the manual for 88-91 Suburban? Would love to see what that bad boy says about shifting into 4L.

I have a manual for a 1990.this website also has manuals.

 

[Frankenchevy]

There’s some small nylon bushings in that TC that wear out and cause difficulty shifting. For what it’s worth, I have a 208 and always shift it at a dead stop. I have to get out to lock the hubs anyway.

 

[Giant Rock]

There’s some small nylon bushings in that TC that wear out and cause difficulty shifting. For what it’s worth, I have a 208 and always shift it at a dead stop. I have to get out to lock the hubs anyway.

Do you put it in Neutral when at a dead stop? Mine does not have locking hubs, or at least not ones you can do manually, I wonder what's up with that?

 

[skysurfer]

My '89 has the 241C. I've always shifted in or out of ANY of the 4x options at a dead stop, engine running, and transmission in neutral. Twenty years this way and no issues. Like Frankenchevy, I have manual hubs but did it the same way when they were auto-lock.