14 bolt center Pinion output centerline
 

I purchased a 72 4x4 with a 14 bolt 8 lug full float axel in the rear. From the top side every thing "looks" right, but I have a vibration. From underneath something looks out of alignment? I am wondering if the rear diff outlet should be centered in the frame. and if that centerline should carry clear through the 205 transfer case and engine.

Re: 14 bolt center Pinion output centerline
 

You got me...not sure what the "rear diff outlet"is...did you mean the pinion shaft and yoke?
Make sure your u-joints are phased correctly..and check the for wear and binding..
Some pics would help

Re: 14 bolt center Pinion output centerline
 

yes the center of the pinion shaft

Re: 14 bolt center Pinion output centerline
 

Maybe I should word this different. Let me try again. Since I believe I am stock back to the rear end. Smallblock engine, th350 tranny, and 205 transfer case. If I had a stock rear end, to my knowledge, which is limited, the drive connecting points would all be centered between the frame rails. Including the center of the pinion shaft on the rear diff? If it were say a 12 bolt? on the 14 bolt that I have. the pinion center looks to be about an inch out out of center of the Frame rails?

Re: 14 bolt center Pinion output centerline
 

your differential is offset but your pinion should be in a line with the rest of the drivetrain
heres a pic of a offset diff,,you can see how its off to one side but the pinion is centered

Re: 14 bolt center Pinion output centerline
 

I definitely have some alignment issues to take care of. Thanks for the pic that is exactly what I have. It looks like I have the wrong crossmember as well this is making the entire engine look crooked. I believe they have done something with the engine mounts to compensate. I will do some more investigating tomorrow.

Re: 14 bolt center Pinion output centerline
 

Make sure your 14 bolt is centered in the frame. The only 14 bolts that have the correct perch spacing are the 1 ton square body 4x4’s. Any others will require the perches to be moved and re welded to the axle to center it. I’d be inclined based off what you are saying that maybe the axle didn’t get centered to the frame. When the axle is centered the pinion will be in a straight line with the transfer case output. My K20 had a hodge podge 14 bolt swap done and it was way off center. Sounds really similar to yours. Here’s a pic after I corrected it.
Also make sure your pinion angle is set right.

Re: 14 bolt center Pinion output centerline
 

Thanks guys , right down the middle will be my goal, I will keep you posted on what I find. I will try to post some photos. If I can figure out how!!!!!

Re: 14 bolt center Pinion output centerline
 

You'll find that it will not be perfectly centered. Not a big deal. Your vibration will be somewhere else. Check u-joints, center bearing and driveline phasing. If ll that fails, have it balanced. OR just take it in to a driveline shop and have it worked over

Re: 14 bolt center Pinion output centerline
 

Re: 14 bolt center Pinion output centerline
 

I do not have a 205, It was a 203 with a part time kit and twin sticks, jurry rigged in there with an altered 205 cross member. No where close to center. It was so crooked they had re drilled the engine mount bracket to get it to bolt down???Im starting over-- transfer case and driveline out (oh yes and drive lines not properly clocked either) transfer case on the ground pulling a used 205 and crossmember from another truck. Once I get that done I will get my pinion angle. Then go back and address the 14 bolt rear end. They had removed and rewelded the perch brackets, but they look to be about 1" out of center. If my angle is wrong as well, I will reweld perches and get everything "right." I hope my photos attach. Thanks for the help Link!

Re: 14 bolt center Pinion output centerline
 

Pics of frame and mis alignment may help

Re: 14 bolt center Pinion output centerline
 

Wow..sounds like a cobbled mess....very nice truck btw..