4wd not stay engaged

[LuckyB50]

87 v10 sm465/208

When I put it in 4hi I need to hold the t-case handle to the rear to keep the 4wd engaged if I move the truck at all. It works just fine in 4lo. What trouble shootimg steps should I run through to diagnose this and rule out what it isn't? What are the probable causes?

 

[MadOgre]

I would suggest adjusting the linkage first before going any further

 

[LuckyB50]

Thanks that seems like a good first step. I'm new to this, are there any good online resources for how to adjust the linkage?

 

[kdo58]

google is the easy way to find it

 

[MadOgre]

No! lol.

Under the cab you have an adjustable sleeve that fits over the threaded rod that connects the floor shifter to the transfer case. There are basically 3 pieces. The floor shifter arm, the adjustable connecting rod, and the transfer case shift arm.

There are 4 positions for the transfer case shift arm at the transfer case. All the way toward the rear of the vehicle is 2H, then 4h, N, and 4L is all the way forward.

So what you want to do is use some penetrating oil and loosen the adjuster assembly and remove it so it is free from the floor shift arm.

Then push and pull to feel where all 4 positions are on the transfer case. Put the transfer case in 4H. So 2nd spot from all the way rearwards.

clean the adjusting rod and parts.

Put the floor shifter in 4H

Now reassemble the adjuster on the adjusting rod and adjust it so that the adjuster fits into the floor shift perfectly, ensuring that both the transfer case and floor shifter are both in 4H.

once that is done back off the rear facing adjuster nut the width of the nut 1/8-3/16". Now push the adjuster assembly rearward to the backed off nut and tighten the forward nut to secure the adjusting assembly tight against the rear nut.

Go into the cab and ensure that all functions properly.

 

[bucket]

Also make sure the engine and trans mounts are good, as well as no body mounts that are broken free.

 

[MadOgre]

Ya that is a good idea! That will affect the distance the transfer case is from the floor shifter. If they are worn out.