Jeep J20 rear axle Dana 60 offset

[FLeetFox]

Ok so I have question, and forgive me, because it may seem a bit dumb and or naive. The J10 I'm building came with a Dana 44 8 bolt front and a Dana 61 rear from a 70s-80's Dodge van. The rear was beat and I wanted to upgrade to 4.10s so it made more sense to upgrade to a Dana 60. I found one reasonable priced, with 4.10s already in it and spring perches in the right place. I t was advertised as a chevy van rear, but down the road I ran the BOM code and it came back as from a 79 J20. Now I realize that the 79 j20 could have had a quadratrac with an offset pinion as an option. I can't find out exactly what the offset was. All I have is my memory to go on and I just remember the pumpkin being practically up against the RH spring packs on the qtracs.

Since pictures always explain better, here is what I have on there now:

[/url]0331191821c by highsiera, on Flickr[/img]

[/url]0331191821 by highsiera, on Flickr[/img]

For a point of reference, the 2x4 on top of the frame is about the center line. The pinion is offset, maybe 4-6" to the pass side. I am going to be running a th400 and a NP208 t-case. And frankly I fretting the drive line angles now. 6" of lift up and down plus 4-6" side to side. Add in that the motor will be putting out much 2.5 times the stock output of torque and HP. I don't want to be eating u-joints like Halloween candy.

Main question is, is this Dana 60 a quadratrac D60? I am interested in people's thoughts on the offset angles given the specs above. I have seen similar driveshaft/ pinion offsets on one or two of Cappa's trucks, but he builds for a different application than I am going for.

All thoughts and inputs are greatly appreciated here.

Fleet Fox

[Stuka]

The 70's J-Trucks all used the same rear axle, regardless of transfer case. As I recall it was just the 3" offset. Wagoneer/Cherokees used more of an offset as they had a shorter wheelbase. So the drive shaft angle would be greater.

That axle should work fine for you. Will clear the fuel tank, and the wheelbase is enough that the NP205 should be fine.

[derf]

The 70's J-Trucks all used the same rear axle, regardless of transfer case. As I recall it was just the 3" offset. Wagoneer/Cherokees used more of an offset as they had a shorter wheelbase. So the drive shaft angle would be greater.

That axle should work fine for you. Will clear the fuel tank, and the wheelbase is enough that the NP205 should be fine.

Agreed. The length of the driveshaft reduces the angle that the u-joint has to deal with in the trucks, especially with a long bed. They ran a center rear output D20 to the offset rear axle from the factory.

Even in the 70's wags and cherokees with the D20, they ran an offset rear so the drive shaft would clear the gas tank. Though I am told (please correct me if I'm wrong) that they had two different offsets in the wag/cherokee. One for the D20 and one for the Qtrac.

[Stuka]

The 70's J-Trucks all used the same rear axle, regardless of transfer case. As I recall it was just the 3" offset. Wagoneer/Cherokees used more of an offset as they had a shorter wheelbase. So the drive shaft angle would be greater.

That axle should work fine for you. Will clear the fuel tank, and the wheelbase is enough that the NP205 should be fine.

Agreed. The length of the driveshaft reduces the angle that the u-joint has to deal with in the trucks, especially with a long bed. They ran a center rear output D20 to the offset rear axle from the factory.

Even in the 70's wags and cherokees with the D20, they ran an offset rear so the drive shaft would clear the gas tank. Though I am told (please correct me if I'm wrong) that they had two different offsets in the wag/cherokee. One for the D20 and one for the Qtrac.

Yes, Wagoneer's and NT Cherokee's had two different offsets. The WT cherokee used a single rear axle that was fit between those two as I recall so that they could reuse one of the axle shafts from an NT to save on cost.

[FLeetFox]

Thank you! Both for you comments, I will sleep much easier. I am going to move forward with it from here. Once the drive train is in I may re-assess, only because D60s pop up for sale here with some frequency and it wouldn't be hard to find a centered pinion replacement with the same gearing for a reasonable price. Your descriptions of the chero and wag axle offsets are inline with my junkyard memories from decades ago. Again, thanks for the knowledge dump.

Fleet Fox

[Stuka]

Thank you! Both for you comments, I will sleep much easier. I am going to move forward with it from here. Once the drive train is in I may re-assess, only because D60s pop up for sale here with some frequency and it wouldn't be hard to find a centered pinion replacement with the same gearing for a reasonable price. Your descriptions of the chero and wag axle offsets are inline with my junkyard memories from decades ago. Again, thanks for the knowledge dump.

Fleet Fox

Unless you change out the fuel tank, a centered rear axle may put the drive shaft into it. The tank was changed in 1980 when they moved to centered axles.

[FLeetFox]

been thinking a lot about adding a 42 gal Suburban tank in the rear...

[bigun]

We tried to run a Ford 9 inch in Crom when he was still a Cherokee got it all bolted in when before we found out that it wouldn't work because of the fuel tank. We talked about changing to a rear tank then the J-20 was offered and the rest as they say is history