2wd to 4wd conversion

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,348
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Okay so this is how it looks so far. Everything bolted in expect shocks and drag link. Did have clearance issues with the exhaust on drivers side and had to cut it out of the way but other then that everything went really smooth. Little tricky lining the holes for back side spring hangers. What do u guys think so far?

You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach

I mean it could look a little nicer in some areas, but as far as a quick and dirty 4x4 conversion goes, you are making it look easy.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,348
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
I’m no expert on it, but all I know is the old saying how’s converting from 2wd to 4wd it won’t ever track down the road straight no matter what you do. I can’t recall who said that to me, but it was many years ago. I’d just get a true 4wd truck, save you troubles.

Whoever said that must not know how to properly read a tape measure.
 

eskimomann209

Full Access Member
Joined
Jan 9, 2019
Posts
1,849
Reaction score
2,005
Location
Modesto
First Name
Marcus
Truck Year
1973
Truck Model
C10
Engine Size
5.3
I’m no expert on it, but all I know is the old saying how’s converting from 2wd to 4wd it won’t ever track down the road straight no matter what you do. I can’t recall who said that to me, but it was many years ago. I’d just get a true 4wd truck, save you troubles.
I have converted more than a couple two wheel drives to 4x4. It’s not that hard. I have done leaf springs, 4 link and radius arms.
Make the front crossmember then measure off it to the rear brackets.
The real issue if uneven is the “crab walk” but it’ll still track strait, If aligned.
 

sirweesarunch

Full Access Member
Joined
Nov 4, 2019
Posts
366
Reaction score
846
Location
Oceanside
First Name
John
Truck Year
1980
Truck Model
K30
Engine Size
454
That's true to, I've left as is for now until I got some feedback, but I'm mostly concerned about the crossmember clearance right now.

This is how everything sits right now, I'm not gunna be doing any offroad use really. Mostly gunna be a Sunday/weekend driver.

You must be registered for see images attach
I salute you my friend. I have a 1 ton dually 4x4 and its totally apart up front. The motor is out and I unbolted all the frame crossover brackets. That whole mass of 2 WD **** is non existent on mine. The cross frame brackets under the motor dont dip any lower than the frame rails. If you have question I’ll post any fotos you need for reference.


Sent from my iPhone using Tapatalk
 

Jarrett Melvin

Full Access Member
Joined
Oct 17, 2020
Posts
93
Reaction score
42
Location
Newfoundland
First Name
Jarrett
Truck Year
1983
Truck Model
C20
Engine Size
350
I understand that switching frames is probably the easiest way or just get a 4wd truck. But where I'm from trucks can be few and far between and the 1 tons are even more rear and the cab and chassis model to the point I only know of 2 besides my own, 4 1 ton trucks altogether, all of which were 2wd. So this conversion was probably my easiest cheapest bet.


Regards to the 2wd drive crossmember. I have another 350 engine there that I'm gunna rebuild to put in this truck. So when the time comes to swap, I'll probably address the cross member then. Until then I may just cut it down and clean it up a bit until then.

But al

You must be registered for see images attach
 

Raybob9289

Full Access Member
Joined
Mar 3, 2021
Posts
60
Reaction score
107
Location
Littleton
First Name
Raybob
Truck Year
1977
Truck Model
Cheyenne 30
Engine Size
454
I'm converting a 77 C30 to K30 I'm using all stock brackets from a 79 K20. I had to get rear front spring hangars from a 82 K30 cab & chassis in the local junkyard.
Does anybody know about the transmission transfercase crossmember? Looks like the only thing I didn't think of...
 

Curt

Full Access Member
Joined
Sep 11, 2017
Posts
676
Reaction score
1,141
Location
Loco Hills
First Name
Curt
Truck Year
1984
Truck Model
K-30
Engine Size
383
Well,the cross member is gonna depend on what transfercase you use?What year the case and adapter is.
 

Raybob9289

Full Access Member
Joined
Mar 3, 2021
Posts
60
Reaction score
107
Location
Littleton
First Name
Raybob
Truck Year
1977
Truck Model
Cheyenne 30
Engine Size
454
Well,the cross member is gonna depend on what transfercase you use?What year the case and adapter is.

SM465 & NP205
I have the cross member from the 79 K20 but since the frame is 2" taller it looks like it'll make the tranny & Tcase 2" lower??
 
Last edited:

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,348
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
SM465 & NP205
I have the crewmember from the 79 K30 but since the frame is 2" taller it looks like it'll make the tranny & Tcase 2" lower??

You mean '79 K20? Yeah, you need a crossmember from a '77-'84 K30, but only if you are using a "figure 8" style 205 with the 10 spline arrangement. If you are using a later style "round pattern" 205 with 32 spline input, you will need a later style crossmember.
 

Raybob9289

Full Access Member
Joined
Mar 3, 2021
Posts
60
Reaction score
107
Location
Littleton
First Name
Raybob
Truck Year
1977
Truck Model
Cheyenne 30
Engine Size
454
You mean '79 K20? Yeah, you need a crossmember from a '77-'84 K30, but only if you are using a "figure 8" style 205 with the 10 spline arrangement. If you are using a later style "round pattern" 205 with 32 spline input, you will need a later style crossmember.

I do have the 79 K20 cross member. I also got my SM465/NP205 from a 76 K20 so I believe it's the figure 8 style?
I think the K30 c&c in my local junkyard was a TH400/NP205. I'm pretty sure the cross member is still under it with the NP205. I'll be there Saturday morning..
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,348
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
I do have the 79 K20 cross member. I also got my SM465/NP205 from a 76 K20 so I believe it's the figure 8 style?
I think the K30 c&c in my local junkyard was a TH400/NP205. I'm pretty sure the cross member is still under it with the NP205. I'll be there Saturday morning..

Well if you are there and have the time, you could probably make some money reselling that 400/205 combo.
 

Raybob9289

Full Access Member
Joined
Mar 3, 2021
Posts
60
Reaction score
107
Location
Littleton
First Name
Raybob
Truck Year
1977
Truck Model
Cheyenne 30
Engine Size
454
Well I got the cross member off the K30 and sure enough its flat compared to the K10 & K20 cross member
You must be registered for see images

You must be registered for see images


You must be registered for see images attach
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,693
Reaction score
6,869
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Well I got the cross member off the K30 and sure enough its flat compared to the K10 & K20 cross member
You must be registered for see images

You must be registered for see images


You must be registered for see images attach
That came for a th400 or a sm465?
 

HOTFOOT

Full Access Member
Joined
Feb 29, 2020
Posts
474
Reaction score
1,041
Location
northwest ct
First Name
michael
Truck Year
1980
Truck Model
gmc k3500 srw
Engine Size
400
Well I got the cross member off the K30 and sure enough its flat compared to the K10 & K20 cross member
You must be registered for see images

You must be registered for see images


You must be registered for see images attach
And it had a skid plate lucky dog, that’s what my 80 k35 needs
 

Forum statistics

Threads
44,169
Posts
950,808
Members
36,286
Latest member
goodwrenchca
Top