Hey guys, back again with a new project - I scored a convertible V6 this time. In the short term it needs some work - we got it running last weekend but there's still a ways to go.

Long-term though, I'm thinking about a 4x4 conversion and I'm trying to figure out how different the 2WD and 4WD frames actually are on the early trucks ('87-'91).

Every thread I can find about 2WD to 4WD swaps is about the mid-to-late '90s trucks or second gens, and the consensus there is that the frames are completely different from the front doors forward. But nobody seems to talk about the early trucks specifically.

Are the '87-'91 2WD and 4WD V6 frames the same basic rails with different bolted-on crossmembers, or are they completely different stampings? If it's just crossmembers and brackets that differ, a 4x4 conversion on an early truck could be way more straightforward than the forums make it sound for the later ones.

Anybody done it on an early 1st gen or have the frame specs handy to compare? Thanks.

So checking out some parts number charts and it looks like these were the part numbers for the frames.

• 4447276 — 2WD, 112" wheelbase (short bed)
• 4447277 — 2WD, 124" wheelbase (long bed)
• 4447278 — 4WD, 112" wheelbase (short bed)
• 4447279 — 4WD, 124" wheelbase (long bed)

That does imply a frame difference between 2WD and 4 WD.

However, the FSM only has alignment spec for one frame, which implies that the frames all share the same alignment specs so they can't be that different.

There will be some additional? brackets on the 4x4 frame. I suspect the control arm mounts are exactly the same. Just mounting for a front drive axle needs to be there on the 4x4.