Axle swap problem

[tonypaul]

Fist day back on my truck project and I hit a wall. I started disconstruction this past winter and then found a drag car that I had to have and so completly redid the car.
So now back on the truck I purchased these 5 lug swap axles from Classic Industries a while back and today decided to do the swap. The problem is that the axles are 3/4 of an inch shorter than the 6 lug axles and theres no way to get the c-clips back on. Anyone run into this problem before? I already emailed Classic but expect not to hear from them till the weekend is over.

The truck is a 1968 GMC swb that came with a 396 big block, and a 12 bolt 3.73 rear. I was told that the drivetrain was all orginal other than the transmission....

Any ideas?
Thanks! (its good to be back here I really missed this forum)

[cdowns]

about the only thing you can do is buy another newset of axels and measure to make sure they are correct this time

the 69-70 6lug axels were wider than the 67-68 sounds like that is your problem

[ERASER5]

70 1/2 rears are wider. 70 was the change over year. You really need to measure the "Wheel mount surface to wheel mount surface." I went and bought a length of angle iron. The thin stuff with lots of hole in it. I bolted it to the drums and measured between. When I compare my measurements to other people's, I have a 1/8" difference. So just call it "purt near."

Some of my info:

Axle from a 1970 ½ Ton GMC leaf spring truck.

63-3/4" Wheel mount to wheel mount
3” Axel tube dia.

Dana 60
Axle from a 1969 ½ Ton Chevy leaf spring truck.

62-3/8” Wheel mount to wheel mount
2-3/4” Axel tube dia.

[raycow]

It's definitely a 70-up rear. The 3/4" difference per side is exactly what it should be. Someone swapped it before the truck got to the person you bought it from. That information just didn't get passed down the line.

I have never dealt with Classic Industries, but if the shafts look unused and the company is decent, I would expect them to give you credit less freight against a pair of the later shafts.

Ray

[Robznob11]

i know of no 70.5 and up rears that had 6 bolts if it is a newer rear they would have had to get custom longer axles with 6 bolts wich is unlikley sounds to me like you got sent the wrong axles and im not positive but im thinking there is only 3/8 diff in the length of the 68 and 72 axles

[lolife99]

Originally Posted by cdowns

about the only thing you can do is buy another newset of axels and measure to make sure they are correct this time

the 69-70 6lug axels were wider than the 67-68 sounds like that is your problem

This is incorrect.
The 71-72 axles were wider than the 67-70 axles by approximately 3/4" per side,... with the following exception

Originally Posted by Robznob11

i know of no 70.5 and up rears that had 6 bolts if it is a newer rear they would have had to get custom longer axles with 6 bolts wich is unlikley sounds to me like you got sent the wrong axles and im not positive but im thinking there is only 3/8 diff in the length of the 68 and 72 axles

There was a transition year for the 6-lug rearends in 1970.
Although kinda rare,... I do own a couple of them.
(one leaf spring GMC and one coil spring type that's in my 1970 stepside.
And I know it's the original rearend)

Most don't talk about '70 model rearend when talking 6-lug vs 5-lug,... because it adds to the confusion.
But at some point in the 1970 model truck,... your truck could have had the narrower 67-70 housing or the wider 71-72 housing.

The narrower rearend should measure approximately 55.5" from "backing plate to backing plate".
The wider housing will measure 57" from the same point.

[cdowns]

[QUOTE=lolife99;4039446]This is incorrect.
The 71-72 axles were wider than the 67-70 axles by approximately 3/4" per side,... with the following exception

WRONG INFO THERE BUD CHECK YOUR FACTS

[lolife99]

[quote=cdowns;4039463]

Originally Posted by lolife99

This is incorrect.
The 71-72 axles were wider than the 67-70 axles by approximately 3/4" per side,... with the following exception

WRONG INFO THERE BUD CHECK YOUR FACTS

I'm not going to start a p#ssing match.
I verified my info with a tape measure on my trucks.
Where did you get your info that the 69-70 were wider that the 67-68?
Just curious.

[lolife99]

You a saying there are 3 different axle housing lengths?
67-68
69-70
71-72
Or just two?

[Shyguy]

I know very little about axles and such compared to you all, but were 4X4 axles 5 or 6 lug after '70?

Just a question for my own info since I am not real knowledgeable about axles and such.

Danny

[lolife99]

Originally Posted by Shyguy

I know very little about axles and such compared to you all, but were 4X4 axles 5 or 6 lug after '70?Just a question for my own info since I am not real knowledgeable about axles and such.

Danny

6-lug.

[chev-obsession]

In custom classic trucks magazine, this month there was an article about a cheap disc brake swap on a '68. They used the spindles off of a '72 i beileve and for the rear to match the front they had the axles sent to a machine shop to be drilled out for the 5 lug on 5'' bolt pattern. If it intrests you, you might go pick it up. That way your using your original axles and they cant be shorter or longer or something else stupid.

[ERASER5]

Proper axle width is measured from wheel mount to wheel mount. Measuring to the back plate is not correct. Not all back plates are the same, most are, but not all.

My 1970 GMC 6 lug GM12 bolt leaf spring truck had the wider axle. The width is exactly the same as my 1972 Chevy 5 lug coil spring truck.

My 69 D-60 6 lug leaf spring axle is narrower.

[chev-obsession]

lowlife99 is right by the way. the '71 and '72 rear ends are wider, last year when i converted to discs in my 69 i had a '71 rear end... i had a posi out of an earlier model axle... say a '69 or something, i took it to the mechanic and i asked him to put the POSI, 5 LUG AXLES, AND PUT THEM IN MY '69'S HOUSING. It would not work. The '71 and '72 axles ARE LONGER. Ended up buying new gears for the '71 housing (because they were 3.08's and my '69's 3.73's were chipped) and i used my posi carrier out of the earlier model. the reason the rears are longer is because the disc brakes are wider than drums were.

[Robznob11]

i know the later axles are longer and i knew that they changed in 70 mid year i just did not know that they retained the 6 bolt pattern. but it sounds like a easy fix and a money saver send the axles back because they are to short and go find a doner rear with 5 bolts they should slide right in. the only thing i was getting at is that if he had the shorter rear and got sent the wrong axles they should have been to long not to short but that changes if gm made the wide housing with a 6 bolt pattern i had never heard of that i always thought they changed bolt patterns at the same time they changed lengths



There was a transition year for the 6-lug rearends in 1970.
Although kinda rare,... I do own a couple of them.
(one leaf spring GMC and one coil spring type that's in my 1970 stepside.
And I know it's the original rearend)

Most don't talk about '70 model rearend when talking 6-lug vs 5-lug,... because it adds to the confusion.
But at some point in the 1970 model truck,... your truck could have had the narrower 67-70 housing or the wider 71-72 housing.

The narrower rearend should measure approximately 55.5" from "backing plate to backing plate".
The wider housing will measure 57" from the same point.[/QUOTE]

[Smith & Sons]

FYI,you can order custom axils from Dutchman.Use their order form & diagram for correct measurements.Mine just arrived,cost 311.00 including shipping.No,its not the price you wanted to hear,but it sure solves the problem & they came in 5 da.