Sprinter 4WD Conversion Idea, GMT-800 IFS.

[luthj]

I finished rewriting the code for the status LEDs. I can't seem to find what I wrote month ago... I glued a weatherproof microswitch for the low range position. I also ordered a protoboard for the Due/CAN-bridge and some logic level FETs. Should be pretty simple to wire up. Hardest part is probably going to be modifying the console, and figuring out connectors.

 

[luthj]

Spent some time in the local junkyard measuring driveshafts and axles.

Looks like 2500 gm axles with stabilitrack will work. Found a nice 2011 savanna 2500. 55 teeth on the tone wheels, and each wheel has one. yoke is ~1.5" farther forward than the sprinters. Leaf springs are about the same length and width. They are about 1.5" farther apart than the sprinter Flange to flange distance is about 69 3/8". So I would need 1" spacers to match the front track width. Brakes are vented discs with integral drum parking brake.

Of course the one and only ABS equipped axle in my local yard is 3.42 gear ratio! So I will start looking at the used parts houses to see if they have a matching unit in 3.73. I am going to need new brackets for everything, but should be doable. I may need to move the axle back an inch to let me use my current driveshaft. otherwise I will need to have it shortened.

Speaking of shortening shafts, I grabbed a front CV driveshaft off a V8 durango. Its about 2" diameter thicker tubing with 5" slip. With the final length being ~22-24", I figure its worth a shot to shorten it on the bench. Plan is to grind the weld off at the male splines, shorten tube, and reweld. I should be able to get the runout reasonable with some vee blocks and my dial indicator.

 

[mountainhick]

Spent some time in the local junkyard measuring driveshafts and axles.

Looks like 2500 gm axles with stabilitrack will work. Found a nice 2011 savanna 2500. 55 teeth on the tone wheels, and each wheel has one. yoke is ~1.5" farther forward than the sprinters. Leaf springs are about the same length and width. They are about 1.5" farther apart than the sprinter Flange to flange distance is about 69 3/8". So I would need 1" spacers to match the front track width. Brakes are vented discs with integral drum parking brake.

Of course the one and only ABS equipped axle in my local yard is 3.42 gear ratio! So I will start looking at the used parts houses to see if they have a matching unit in 3.73. I am going to need new brackets for everything, but should be doable. I may need to move the axle back an inch to let me use my current driveshaft. otherwise I will need to have it shortened.

Speaking of shortening shafts, I grabbed a front CV driveshaft off a V8 durango. Its about 2" diameter thicker tubing with 5" slip. With the final length being ~22-24", I figure its worth a shot to shorten it on the bench. Plan is to grind the weld off at the male splines, shorten tube, and reweld. I should be able to get the runout reasonable with some vee blocks and my dial indicator.

What size ring gear on that axle??

 

[luthj]

What size ring gear on that axle??

9.75" I believe. Though 10.5 was an option.

 

[mountainhick]

9.75" I believe. Though 10.5 was an option.

Aftermarket lockers?

 

[luthj]

Aftermarket lockers?

Looks like ARB and Eaton have offerings. 33 spline axle shafts, non removable pinion support. If I am reading the catalog right, its actually the same diff core as the front diff. So the RD197 ARB locker will fit.

 

[luthj]

Here is some photos. Looks like a 9.5" 14 bolt. 2 wire ABS sensors (not sure what type). The diff core should be the same from 97-14 according to the internet.

 

[mountainhick]

Here is some photos. Looks like a 9.5" 14 bolt. 2 wire ABS sensors (not sure what type). The diff core should be the same from 97-14 according to the internet.

Yes that looks like my 9.5",

6 or 8 bolt wheel mount? Hard to tell from pic.

 

[luthj]

8 bolt hubs with the early pattern.

I am not sure but at some point they changed bolt patterns to the larger 8 lug. Maybe 2012? Though the vans are always slow to get changes. I was looking at an early axle, and I wonder if the later shafts (with tone rings) would fit on an early axle? Some drilling to fit the sensor would be necessary.

 

[luthj]

Got busy with the temp driveshaft.







A fair bit needed to come off.









I had to grind a bit out of the bore ID to get the slip to fit in. It is apparently a press fit (about 7 thousands interference), and I don't have a press. Once I got it assembled, I mounted it up and put my dial indicator on it. A few minutes of tapping with the mallet got it to 0.005" of runout




I welded in 4 places 180 degrees opposite to keep the heat even. Final runout is about 10 thousands, which is reasonable I think.



Sorry for the crappy focus.



You can see the clearance here.





I need to find the correct straps for the pinion yoke, and I can take it for a test drive.

 

[mountainhick]

8 bolt hubs with the early pattern.

I am not sure but at some point they changed bolt patterns to the larger 8 lug. Maybe 2012? Though the vans are always slow to get changes. I was looking at an early axle, and I wonder if the later shafts (with tone rings) would fit on an early axle? Some drilling to fit the sensor would be necessary.

Yes, I am pretty sure right around 2011-2012. They also changed the tone ring count to I think 88. But likewise don't know about the vans. When I was shopping around seemed there was different track width for van vs pickup, so I am not too sure whether axles can be interchangedbetween them. My axle is off a GMC Sierra. I still have the tone ring project ready to go, so no worries there, but for future reference having a 55 tooth off the shelf axle with integral TR would be a boon.

If you get that axle we could compare axle shaft lengths. My shafts are out to do the tone ring work.

 

[Buddha.]

The HD trucks changed in 2011, the HD suburbans were changed later. Not sure about the vans.

 

[luthj]

Took the van for a drive. No major issues to report. I still have a clunk on the driverside, need to go through bolts again. I have some driveshaft vibration over 55. I am not sure if its just balance, or I need to adjust the pinion angle.

 

[mountainhick]

Took the van for a drive. No major issues to report. I still have a clunk on the driverside, need to go through bolts again. I have some driveshaft vibration over 55. I am not sure if its just balance, or I need to adjust the pinion angle.

Did you have the chance to engage 4wd with the new front DS?

 

[luthj]

Did you have the chance to engage 4wd with the new front DS?

That's on the list for later today. I couldn't remember which position was 4PT or 4FT. I didn't want to snap a UJ putting it in 4PT by accident.

I should be getting the last of the parts for the indicator panel today. Should be able to wrap that up by the end of the week.