Another axle swap question

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.

adaml23

Full Access Member
Joined
Jun 16, 2014
Posts
115
Reaction score
4
Location
Decatur, IN
First Name
Adam
Truck Year
1979
Truck Model
Scottsdale
Engine Size
400
Hey everyone,

So I'm looking to get my dad's old K10 Scottsdale 400 sb running and need some help with getting another axle put in the rear. The plan with this truck is ~80% on road use with plow capabilities and occasional light off-road fun.

The truck currently has 3.08s 6 lug in the front and rear and the rear is toast. It's a gov-lock 12 bolt.

I've possibly got a lead on a set of Dana 44 front and rear 3.73s. 12 bolt rear 6 lug with new wheel bearings, seals, acdleco ball joints, u joints and it is a big bearing 44. He wants $300 total for both.

Pretty sure up to this point everything should swap over, right? But it also has the flat top knuckles on the front. I plan on either leaving the truck stock height or possibly no greater than a 3 inch lift with some larger tires.

Question is, do I (or can I) use the flat top knuckles with no (or not much) lift and leaving the steering stock? Don't really want to mess with the steering actually. If the flat top knuckles won't work, can I just re-use the current knuckles that are on the truck and remove the flat top knuckles if I can't use them (I'd rather not do this as its prolly more work...:) )

Let the educating begin...
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,356
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
The knuckles will work just fine. It's just that the early passenger knuckles have the flat area on top like every driver side knuckle, which is useful for converting to crossover style steering. GM didn't make use of that flat top, neither do you.

But, you can sell them and reuse your stock knuckles if you want to recoup a little money.
 

CSFJ

-----------------
Supporting Member
Joined
Jul 1, 2014
Posts
6,160
Reaction score
5,170
Location
------
First Name
-------------
Truck Year
-------
Truck Model
-------
Engine Size
-------
yep, what Bucket said. I don't know how sought after the flat top knuckles are for trucks like these, but I do know the jeep guys are always looking to do cross over steering on the Dana 44 axles.
 

marks86

Full Access Member
Joined
Feb 2, 2011
Posts
1,513
Reaction score
90
Location
Latham, NY
First Name
Mark
Truck Year
1986
Truck Model
K30
Engine Size
12v Cummins
a fully rebuild axle set for 300bucks does not sound right to me, if so buy them
 

adaml23

Full Access Member
Joined
Jun 16, 2014
Posts
115
Reaction score
4
Location
Decatur, IN
First Name
Adam
Truck Year
1979
Truck Model
Scottsdale
Engine Size
400
I kinda thought it was too good as well. Can't get ahold of the guy so they may be sold already or something...

Another question tho, how common were 3.42 gears for our truck's? That's the gearing I think I'd like but haven't really seen many. What's a good price for a good used set of them for front and back?
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,356
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 had a matching set of 3.42 geared 10 bolts at one time. I couldn't even give them away. A little ironic, they were later stolen for scrap.
 

CSFJ

-----------------
Supporting Member
Joined
Jul 1, 2014
Posts
6,160
Reaction score
5,170
Location
------
First Name
-------------
Truck Year
-------
Truck Model
-------
Engine Size
-------
I kinda thought it was too good as well. Can't get ahold of the guy so they may be sold already or something...

Another question tho, how common were 3.42 gears for our truck's? That's the gearing I think I'd like but haven't really seen many. What's a good price for a good used set of them for front and back?

I know the '79 half ton i had in high school had the 3:42 gear set, and I'm pretty sure the '84 half ton i had had them as well. I always thought that ration was pretty common in the light duty 4x4 trucks, and the blazers and short box trucks usually got the 3:08s.
 

Don5

Full Access Member
Joined
Oct 5, 2014
Posts
1,136
Reaction score
73
Location
West Virginia
First Name
Don
Truck Year
1979
Truck Model
k15
Engine Size
350
I read somewhere that the 3.42 gearing was used only in standard transmission trucks. My 79 half ton 4x4 came with 3.08 from the factory. It also had a auto transmission and 203 full time transfer case.
 

marks86

Full Access Member
Joined
Feb 2, 2011
Posts
1,513
Reaction score
90
Location
Latham, NY
First Name
Mark
Truck Year
1986
Truck Model
K30
Engine Size
12v Cummins
I read somewhere that the 3.42 gearing was used only in standard transmission trucks. My 79 half ton 4x4 came with 3.08 from the factory. It also had a auto transmission and 203 full time transfer case.

I had 3.42's in my 86 k10 4.3/700r4
 

Don5

Full Access Member
Joined
Oct 5, 2014
Posts
1,136
Reaction score
73
Location
West Virginia
First Name
Don
Truck Year
1979
Truck Model
k15
Engine Size
350
I had 3.42's in my 86 k10 4.3/700r4

I read about the 3.42's somewhere in a gm publication or maybe a four wheeler mag article I forget. I would say that since you had the 4.3 that was probably why the 3.42's were put in. :)
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,356
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Mine were originally from my '88 K10 Burb with 350 and 700r4.
 

marks86

Full Access Member
Joined
Feb 2, 2011
Posts
1,513
Reaction score
90
Location
Latham, NY
First Name
Mark
Truck Year
1986
Truck Model
K30
Engine Size
12v Cummins
Im going to guess that 3.42 gears were an option with a 700r4
 

CSFJ

-----------------
Supporting Member
Joined
Jul 1, 2014
Posts
6,160
Reaction score
5,170
Location
------
First Name
-------------
Truck Year
-------
Truck Model
-------
Engine Size
-------
My '79 was built with the 350/350/203 driveline with the 3:42 gearset. I wish i knew for certain what my '84 had. It was a 305/465/208 combo. The only thing i know for certain, is that it had a limited slip in the rear diff. I always thought it had the same ratio as the '79, but never actually checked.
 

adaml23

Full Access Member
Joined
Jun 16, 2014
Posts
115
Reaction score
4
Location
Decatur, IN
First Name
Adam
Truck Year
1979
Truck Model
Scottsdale
Engine Size
400
BTW just an update, but the guy finally got back with me and had sold them... Dang.

With a 400 ci motor and 32 inch tall tires, what would you guys think would be the better option between 3.42s and 3.73s? It's gonna mostly be used for on-road driving with intermittent highway and plowing useage.

Or would you say it won't be a noticable difference between the two and to just get whichever one I can get at a good deal?
 

Forum statistics

Threads
44,174
Posts
950,902
Members
36,291
Latest member
tannerscarber
Top