2WD to 4x4 conversion?

[75gmck25]

4.10 ratio is a very common gear ratio on the early 4x4 3/4 ton trucks like my ‘75 K25, but I’m not sure about later trucks. With 31” tires (245/75R16E) and a TH350 it runs about 2800 rpm at 60 mph, so still within a reasonable range.

You could bolt the suspension and drivetrain from my k25 onto almost any squarebody truck, as long as it has the high cab hump to clear the transfer case. My truck is a camper special 3/4 ton with the 8400 GVW package, so it has the 14 bolt FF axle with 4.10 gears, 7 leaf rear springs and 5 leaf front springs, front sway bar, etc. It’s very durable, and really useful as a work truck, but truly rides like a truck. YMMV

Bruce

 

[80BrownK10]

Yeah, I knew I would most likely need a donor truck to make the swap easier. The only reason I’d rather convert it than sell it and buy a different one is because it’s my first one and I want to keep it in the family. Do some 4x4’s have 4.10 gearing?


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Yes

 

[Curt]

Also,you could add a rear locking differential to your current truck and would extremely surprised at its new capabilities.Then if you do turn your truck into a 4WD,your rear axle will be ready.In the mean time,you can source a donor truck or you may end up liking your donor so much,you just fix it up.

 

[Differentdanyou]

Also,you could add a rear locking differential to your current truck and would extremely surprised at its new capabilities.Then if you do turn your truck into a 4WD,your rear axle will be ready.In the mean time,you can source a donor truck or you may end up liking your donor so much,you just fix it up.

Do stock K10’s come with a locking rear diff?


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[crpntr78]

My 84 K2500, 8600 GVW has 4:10 gears.

 

[75gmck25]

The typical locking differential option on these trucks is the GM Gov Lock, and many of them have been abused, and have broken.

Its better to get a truck with an open rear differential and add an aftermarket limited slip or locking differential on the rear axle. Take a look at the Summit racing offerings online and you will see some of the aftermarket choices.

Bruce

 

[Powerhouse Ranch]

Main differences between 2wd and 4wd is the springs/coils in the front turn to leaves and a differential added in front, obviously. highly suggest swapping body onto a 4wd frame, would be alot easier. keep in mind you'll need to cut a whole in the floor of your cab for the 4x4 shifter

 

[Turbo4whl]

Do stock K10’s come with a locking rear diff?


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No, always an option on 2 or 4 wheel drive. Not part of the 4 wheel drive option.

 

[Differentdanyou]

Main differences between 2wd and 4wd is the springs/coils in the front turn to leaves and a differential added in front, obviously. highly suggest swapping body onto a 4wd frame, would be alot easier. keep in mind you'll need to cut a whole in the floor of your cab for the 4x4 shifter

What would be harder about not swapping frames? My frame I have is mostly rust free and I live in Illinois where that’s kinda rare. Would the hardest part be the clearance hump for the transfer case?


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[Powerhouse Ranch]

What would be harder about not swapping frames? My frame I have is mostly rust free and I live in Illinois where that’s kinda rare. Would the hardest part be the clearance hump for the transfer case?


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yeah i've heard problems with that. depends on your skill level really. you'll have to tear apart your front suspension and practically start from scratch, know your exact measurements as to where all of the 4wd pieces go, you'll have to get a good new front axle, a transfer case that matches your hubs, driveshafts, etc. this is the tip of the iceberg. i'm no pro in such a swap without doing the entire frame, but i can guarantee its meticulous. it is possible and would be a hell of a "been there done that" but time and frustration can be saved investing in a new 4wd frame. and heck, you could either save your 2wd frame down the road as a parts frame, or part it out or literally anything else. either way, good luck sir!

 

[AKguy]

You are in for a lot of work and hassles, but hey, keeps a guy out of the bars! If I were crazy enough to do it again ( I am putting 1981 C20 metal on a 1979 K30 frame/running gear) I would make sure my donor was the same year. That saves some issues.

 

[Differentdanyou]

yeah i've heard problems with that. depends on your skill level really. you'll have to tear apart your front suspension and practically start from scratch, know your exact measurements as to where all of the 4wd pieces go, you'll have to get a good new front axle, a transfer case that matches your hubs, driveshafts, etc. this is the tip of the iceberg. i'm no pro in such a swap without doing the entire frame, but i can guarantee its meticulous. it is possible and would be a hell of a "been there done that" but time and frustration can be saved investing in a new 4wd frame. and heck, you could either save your 2wd frame down the road as a parts frame, or part it out or literally anything else. either way, good luck sir!

Well my buddy has a k10 I could reference [emoji2369] but his is a 79 and mine is an 84. We both have 8ft beds and single cabs. I have no doubt it will be difficult and take a decent amount of time. Thank you for the info though, I will try and keep people updated when I start the swap though


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[Differentdanyou]

You are in for a lot of work and hassles, but hey, keeps a guy out of the bars! If I were crazy enough to do it again ( I am putting 1981 C20 metal on a 1979 K30 frame/running gear) I would make sure my donor was the same year. That saves some issues.

That’s what I was thinking


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[bucket]

Is it just a regular cab truck with a long bed? If so, you would be time and money and frustration ahead by just swapping your good engine, cab and bed onto a rolling 4x4 frame. I'm all for doing conversions if it's something harder to find like a Crew Cab or Suburban. But a standard pickup, it's really not worth it unless you are building a highly modified truck anyway and are used to the work involved.

There's a LOT of details that need tended to. Without going into great detail, here's a short list:
Front spring hangers/core support mounts
Engine mounts and crossmember
Front brake lines
Front spring shackles and associated frame surgery
Steering box and linkage
Trans crossmember
Trans/t-case floor hump surgery
Removal of driveline carrier crossmember
Rear spring hangers
Rear spring shackle hangers

NONE of the holes are already in the frame and not everything fits right into the rails without some amount of cutting/fabrication. Like the engine crossmember and the front spring shackle hangers.

 

[Differentdanyou]

Is it just a regular cab truck with a long bed? If so, you would be time and money and frustration ahead by just swapping your good engine, cab and bed onto a rolling 4x4 frame. I'm all for doing conversions if it's something harder to find like a Crew Cab or Suburban. But a standard pickup, it's really not worth it unless you are building a highly modified truck anyway and are used to the work involved.

There's a LOT of details that need tended to. Without going into great detail, here's a short list:
Front spring hangers/core support mounts
Engine mounts and crossmember
Front brake lines
Front spring shackles and associated frame surgery
Steering box and linkage
Trans crossmember
Trans/t-case floor hump surgery
Removal of driveline carrier crossmember
Rear spring hangers
Rear spring shackle hangers

NONE of the holes are already in the frame and not everything fits right into the rails without some amount of cutting/fabrication. Like the engine crossmember and the front spring shackle hangers.

Why would the engine mounts be different? Also it is a single cab long bed but it has a flatbed idk if that matters.


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