Sprinter 4WD Conversion Idea, GMT-800 IFS.

[Mwilliamshs]

...The second will control winter mode, not 100% sure what all that does, but it seems possible to toggle it via canbus. Hopefully I can turn it off.

Winter drive (aka snow mode) locks-out 1st gear, causing takeoff to occur in 2nd gear. It's designed to reduce wheelspin. It also lowers and softens shift points to ease transitions and reduce the chance of breaking traction.

Same idea is used by isuzu, the winter button (next to the power button) on their autos does the exact same thing.

Similar to a strategy Ford used since at least the 1960s, put the automatic shifter in 2, it starts in 2nd, not 1st.

Land Rover does the same, albeit exaggerated, thing with their drive mode knob: winter starts in 2nd gear and limits engine braking, mud raises shift points and limits upshifts, rock increases engine braking and raises shiftpoints, etc.

 

[roving1]

Working through my code for the canbridge. I currently have it setup to lock out 1st gear in low range (its crazy low for anything but crawling). I have 1 spare wire in my Ethernet cable, but I want to wire two switches. Since I have 3.3V at the panel, I am going to use a couple resistors and 2 switches through an analog input. With a voltage divider, the analog input will see different voltages for SW1, SW2, and SW1+SW2. That will let me toggle their variables in the code. One switch will control 1st gear lockout, so if I really need 1st gear, I can enable it. The second will control winter mode, not 100% sure what all that does, but it seems possible to toggle it via canbus. Hopefully I can turn it off.

I am always amazed and envious of the knowledge, skills and determination of this build. But at times while reading the updates a small part of me is also deliriously happy all my vehicles have manual transmissions, no ABS and no DSC. ?

 

[luthj]

Winter drive (aka snow mode) locks-out 1st gear, causing takeoff to occur in 2nd gear. It's designed to reduce wheelspin. It also lowers and softens shift points to ease transitions and reduce the chance of breaking traction.

Same idea is used by isuzu, the winter button (next to the power button) on their autos does the exact same thing.

Similar to a strategy Ford used since at least the 1960s, put the automatic shifter in 2, it starts in 2nd, not 1st.

Land Rover does the same, albeit exaggerated, thing with their drive mode knob: winter starts in 2nd gear and limits engine braking, mud raises shift points and limits upshifts, rock increases engine braking and raises shiftpoints, etc.

I need to do some testing, but winter mode seems to do something slightly different on the sprinter. Of course I may actually be toggling a completely different mode, as the sprinter never came with a winter switch that I know of. At least I am not likely to break anything...

I am always amazed and envious of the knowledge, skills and determination of this build. But at times while reading the updates a small part of me is also deliriously happy all my vehicles have manual transmissions, no ABS and no DSC. ?

Thanks for the vote of confidence. The ESP/ABS stuff wasn't too big a deal, other than low range. But that's actually a transmission specific issue. As much as a purely mechanical setup may have made things easier, the few safety features the van has do improve the safety margins. The brake force assist has saved my bacon a few times already.

As much as I like the idea of a manual trans, having driven several heavy vehicles with limited horsepower, I really enjoy the auto on the van. My daily driver weighs 3,000lb and has a manual trans, plenty of fun there.

 

[luthj]

Started tearing down the axle. Its got some light rust, so it will get a wash and remediation, followed by epoxy primer and paint. Bearings were all serviceable, but showing their age. There was very little preload on the carrier and pinion bearings. The PS axle seal was weeping a bit as well. Axle shafts mic out okay, so it will get new bearings and seals all around. My bearing puller broke on the wheel bearing, so I need to fix or borrow another. My bearing separator isn't big enough for the pinion bearing, so I need to get some longer studs and modify it. I don't want to hack it off, as I need a setup bearing set. The plan is to use poor mans liquid nitrogen to shrink the pinion and carrier to fit the new bearings.



Anybody need a 3.42 R&P?

 

[b dkw1]

Get a solid pinion spacer, crush sleeves suck balls.

 

[luthj]

Get a solid pinion spacer, crush sleeves suck balls.

Yeah, got that on the list.

 

[Mwilliamshs]

I need to do some testing, but winter mode seems to do something slightly different on the sprinter. Of course I may actually be toggling a completely different mode, as the sprinter never came with a winter switch that I know of. At least I am not likely to break anything...

That's how every other Mercedes I know of does it. Jeeps too.

 

[luthj]

Chipping away at the axle. Got it fully torn down, brackets cut off, and bearings out.


I spent an couple hours at the junkyard, none of the 3.73 R&Ps were fresh enough for me. Wear was marginal. One was okay, but it was sitting on the wheels, and I couldn't get the axle shafts out if I wanted to. I ordered a low mile used one of ebay.

Bearings, calipers, seals, and an ARB locker are in the mail. As are wheels and tires. Backing plates and Ebrake hardware was alright, just a little rusty, so its soaking in a rust converter. I started sanding the case down for paint. My plan is to put the old differ carrier and the wheel seals/bearings in. That will let me bolt it up to set the pinion angle with the springs loaded. I can weld, paint, then get the R&P dialed in.

Hopefully the donor springs work out. I don't mind adding a 1" spacer block. Easiest method would be to add a couple extra leafs I think.

 

[mountainhick]

ARB locker in the mail.

Wha? I looked and found nothing for 9.5" GM... what did you find?

 

[luthj]

Wha? I looked and found nothing for 9.5" GM... what did you find?

This unit. The 9.25IFS and 9.5 AAM (GM corporate 14 bolt) share the same differential carrier. Not to be confused with the 10.5" 14 bolt full float.

Amazon.com: ARB RD197 Air Locker Differential Shaft Spline 33 Ratio All AAM 925/950 Air Locker Differential: Automotive

Buy ARB RD197 Air Locker Differential Shaft Spline 33 Ratio All AAM 925/950 Air Locker Differential: Differential Assembly Kits - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

A few folks make Gov/G80 style lockers, There is the positraction clutch style, and a torsen/helical LSD is available.

GM 9.5'' 14 bolt Rear, 33 spline, Auburn High Performance LSD

GM 9.5' 14 bolt Rear, 33 spline, Auburn High Performance LSD Auburn Gear. Performance Differentials.

www.justdifferentials.com

914A538 Detroit Truetrac Limited Slip GM 9.5" 14 Bolt

914A538 Detroit Truetrac Limited Slip GM 9.5" 14 Bolt<br /> APPLICATION: GM 9.5" 14 Bolt<br /> AXLE PLACEMENT: REAR<br /> AXLE SPLINE COUNT:33<br /> SPLINE DIAMETER:1.37"<br /> COVER: 14 BOLT <br /> GEAR RATIO: ALL RATIOS<br /> MODEL:GM 9.5" <br /> RING GEAR DIAMETER:9.5" <br /> NOTES: GM 9.5"...

www.drivetrainamerica.com

https://www.amazon.com/Yukon-Gear-YDGGM9-5-33-1-Positraction-Differential/dp/B00AWE6CJ2

If you want a G80 locker, there is one in my local yard. I was going to pull the R&P, but the backlash was a bit much.

 

[mountainhick]

This unit. The 9.25IFS and 9.5 AAM (GM corporate 14 bolt) share the same differential carrier. Not to be confused with the 10.5" 14 bolt full float.

Amazon.com: ARB RD197 Air Locker Differential Shaft Spline 33 Ratio All AAM 925/950 Air Locker Differential: Automotive

Buy ARB RD197 Air Locker Differential Shaft Spline 33 Ratio All AAM 925/950 Air Locker Differential: Differential Assembly Kits - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

A few folks make Gov/G80 style lockers, there is also a torsen/helical LSD availble.

GM 9.5'' 14 bolt Rear, 33 spline, Auburn High Performance LSD

GM 9.5' 14 bolt Rear, 33 spline, Auburn High Performance LSD Auburn Gear. Performance Differentials.

www.justdifferentials.com

914A538 Detroit Truetrac Limited Slip GM 9.5" 14 Bolt

914A538 Detroit Truetrac Limited Slip GM 9.5" 14 Bolt<br /> APPLICATION: GM 9.5" 14 Bolt<br /> AXLE PLACEMENT: REAR<br /> AXLE SPLINE COUNT:33<br /> SPLINE DIAMETER:1.37"<br /> COVER: 14 BOLT <br /> GEAR RATIO: ALL RATIOS<br /> MODEL:GM 9.5" <br /> RING GEAR DIAMETER:9.5" <br /> NOTES: GM 9.5"...

www.drivetrainamerica.com

https://www.amazon.com/Yukon-Gear-YDGGM9-5-33-1-Positraction-Differential/dp/B00AWE6CJ2

If you want a G80 locker, there is one in my local yard. I was going to pull the R&P, but the backlash was a bit much.

Hot dang. I have the G80, and did find the posi and lunchboxes previously but not ARB. Possible future upgrade...

EDIT: Hmm, I had indeed found that previously, but found no reference to compatibility with 9.5" rear, only 9.25 front. Anyway, looking forward to seeing how it works out on yours. I will be driving the G80 for a while before jumping on the ARB.

 

[luthj]

Its not a terribly difficult install, but make sure you have a carrier shim kit and marking paint on hand. Its about 80% chance the new diff will need a different shim. Remember that you need a compressed air source. ARB has some compact compressors, VIAIR also has a couple cheaper units.

 

[luthj]

Some odd trans behavior to report. I was doing some driving with the updated program, and it got a bit odder than before. This time it would repeatedly go into LHM. I got codes on the ECM for TCM faults (2228 and 2211), as well as slipping trans faults on the TCM. I was watching the live data, and the TCM would randomly report the rear wheel speeds as the max value of 2500rpm, and then they would drop down to zero (this was parked). The starter lockout contact was reported as implausible as well. Given the CAN codes, I tried fiddling with the program a bit, but no success. So I reverted to the CAN bridge only program, with no LEDS, low range, etc. It works fine now.

To recap, it sounds like missing CAN frames can cause slipping trans codes, abrupt shifting, and other strangeness.

Now I just need to figure out what in my software/hardware setup is causing this issue. am I just getting interference from somewhere? Is the program too slow, and dropping frames? Going to take a bit of trial and error I think, and its not 100% consistent either.

In other news, I have a large pile of parts on my living room floor. Just waiting on the diff, R&P and wheels. Should have all that by Saturday.

 

[mountainhick]

Just waiting on the diff, R&P and wheels. Should have all that by Saturday.

Which wheels are going for?

 

[luthj]

Which wheels are going for?

I went with 5 hole factory steels in black. No plastic cover. I will probably use chrome capped lugs and paint the hub black to match.

Steel Wheel, Rim 16x6.5 - 5195

Transwheel Steel Wheel, Rim 16x6.5, 8x6.5 Bolt Pattern, 5 Spoke - 5195

www.wheelstiresandmore.com