Rear axle pinion off-set

[treetopflyer]

Hey guys, looking at cutting down a Dana 60 out of a E350 van. My question is "what is the rear pinion off-set"?, i.e. is the pinion directly behind the Dana 20 rear output or off to the right or left...NOTE: don't let the differential housing fool you...the pinion itself is not in the center of the "3rd member".
Is there an issue if the driveshaft angles left or right or must it be parallel to the frames/ 90* to the face of the transfer case rear output.
I don't have the body off of my truck to get accurate measurements and can’t find a diagram that shows the information I’m looking for. Hope I explained this clearly enough? A pictures worth a thousand words.

 

[treetopflyer]

stock rear axle dimensions

All right guys...this has been posed for 8 days and no bites. Let me pose this another way. To make my donor REAR Dana 60 axle, B.O.M 606522-3, fit my69 EB (58"WMS-WMS), I'll have to cut both sides down. If I just cut down the long side, the differential will not be centered. I tried to measure the stock ford 9", but I couldn't get accurate measurements with the body still on the frame. I can't tell if the stock rear driveshaft runs straight back to the rear pinion OR if it's angled left or right, and if so how much?

Clear as mud? I thought so...if the rear D/S does angle left or right I'd like to know the dimensions so I can cut my new axle to match or even correct the offset so the T-case output and the rear pinion yoke are in line.

Anybody got the body off their EB with the 9" still under it? Could you drop a few plumb lines and get some measurements? You know the old adage “measure twice, cut once”
Thanks

 

[Explorer]

I'm at the perfect point to measure for you except for one thing, my third member is out being repaired. Hopefully someone will help you this time.

 

[treetopflyer]

Explorer...thanks man! I'm not in a rush (weeks not days). If you don't mind following up with this That would help me a bunch.

P.S. did I make my request clear? Sometimes I type in what I think is great detail, but it doesn't make sense to anyone but me!

 

[Explorer]

I should have it back long before then. If it helps any, the center of the Dana20 output shaft is offset 2" towards the passenger side.

 

[Broncobowsher]

I have layed out a few drivetrains in the past. as much as you think the driveshaft points straight back at the axle, it doesn't. I was amazed to find out how croocked some engines sit in the frame. Pull a straight line from the center of the pinion to the center of the damper on the engine and nothing lines up. Not sure if the Bronco follows this.

I have sen a Jeep with an axle swap. Dana 18 T-case with offset rear output and AMC20 rear end with centered pumpkin. Driveshaft was at a funny sideways angle and the owner drove it without issues.

 

[treetopflyer]

Explorer, thanks...I did see the XFER case is offset, but couldn't get a accurate reference for measurement. I tried to get a straight edge between/ across the frame rails but with the dual exhaust and plumbing, no luck...keep me in mind when you get your diff. back and installed.

 

[treetopflyer]

Broncobowsher...That's what I've seen (jeeps), some D/S's not only slope down (as all D/S's do) but also angle side to side. I agree that it shouldn't be an issue (+- an inch or so), but I'm no Driveshaft guru and was curious about compound angles. I still need a left to right measurement so I can get my dana 60 cut soon.

Thanks guys

 

[TBS-POPS]

Just cut it so the housing is centered. thats the way a full width nine inch is. the pinion IS off to the pass side.

 

[siderbox]

I'm with Broncobowsher. I too have set more than a few 'one off' chassis.
The pinion angle is WAY more important than the offset.
You can put the offset just about anywhere you want.
Have you ever looked under a LandRover?

 

[broncodriver99]

I'm getting 10-7/8 from inside pass frame rail 12-5/8 from drivers.

 

[treetopflyer]

Roger that on pinion angle...but is there a plus or minus to moving the rear diff. to one side or the other... (Light goes off)...unless I built it to match the FRONT offset...think about clearing a rock or obstacle...both diff's would be aligned and you choose a line that wouldn't smash them...thoughts, criticism, cheers? Did I mention that I love this site? well I do...group hug and kumbaya to all.

 

[broncodriver99]

My D20 output shaft measures right at 10" from pass. rail.

 

[Steve83]

Read this & you'll be a driveshaft guru:

 

[treetopflyer]

Steve83...U da man!
Thanks for the diagrams. That made things much clearer. I also liked the recommended balancing speed of 3000rpm vs. 500rpm and how the factory marks the high & low balance points of a given shaft to retain proper balance and orientation during assembly. Good questions to ask when searching for a driveshaft builder. Anyone ask this of Tom Woods or Jesse at High angle? Those two seem to have the best reputation on this forum.

 

[gddyap]

The pinion offset of the 3rd member should be standard and easily found. As far as how much more offset there is on an EB, find out what the length difference is between the two axle shafts. Add that to the offset of the 3rd member and you should get the total offset. If you aren't too worried about the offset, you should see how much it is if you position the diff so that the two axle shafts are the same length. Then you only need one spare shaft.

 

[treetopflyer]

gddyap...it's thinking like that that helps guy's like me. For my project (cummins 4BTA swap), I'm juggling all kinds of systems at the same time i.e. transmission/ Overdrive/transfer case adaption, engine mounts, intercooler/radiator configuration, VAC to Hydro boost, Hyd. clutch (internal slave) to master cyl. ratios, electrics...

So when you made the suggestion about equal length driveshafts fore & aft, the light bulb lit up again! Make perfect sense for this rig...I'm looking to build a rig I can go exploring, not hard core rock crawling, so I need to be self-sufficient, I plan on going remote (think Camel trophy truck, not rock buggy).
Keep the good ideas coming!

 

[KyleQ]

If you are not out for ordering custom shafts, I would say offset the differential to the driver's side about equal to the front - this will not only help protect the drive shaft but you won't hang the rear end up on obstacles.

 

[treetopflyer]

KyleQ...thought about that in post #12. Makes sense. I think the axle cut will wait until I fine tune my direction (align front and rear diff's for more favorable obstacle clearance or off set rear the amount required so both F&R D/S's will be equal length?) More research required.

 

[gddyap]

Currie will build axle assemblies to stock Bronco measurements so you could ask them what the axle shaft lengths and offset are.