37s

[TerraMechE]

Mind elaborating on your regear setup some more? Wild build.

Sure.

Disclaimer: Don't take anything I say as accurate information; I wouldn't trust me. I'm still expecting to find something I missed or did wrong. Information on this diff is a bit scarce and so I likely made some potentially incorrect assumptions. This is an experiment in cheapness and potato-heading parts not necessarily designed to work together. This was also the first clamshell-style diff I've done.

My motivation for doing this is not terribly rational... Money could solve this problem better. I do find getting to know trucks and dirt bikes and farm equipment in these kinds of ways does come in handy when an improvised field fix is needed. I'm really starting to love this truck and I intend on getting dumber with it for years to come.

Anywho...

Parts:
Dana Spicer 10130628 - Differential Case Assembly and Gear Set (Bronco 4.46 pinion, welded ring gear and carrier)

Spicer 10267426 - 21-22 Ford Bronco Differential Rebuild Kit (comes with bearings, shims, gasket maker and patterning paint)

Axle and pinion seals can be found from an online dealer parts fiche. I don't have those numbers handy.

How I did it, roughly:
I couldn't find much in the way of torque-to-rotate and backlash specs for the M190 diff, so took a SWAG by referencing the Jeep M186 specs and taking measurements off the stock unit as I disassembled it. I referenced Toyota IFS diff rebuild procedures, as well. That got me in a decent ballpark.

If you want to do this on your own, buy all the diff-related tools listed in the Ranger service manuals that you can along with general diff rebuild tools, especially a menagerie of bearing and bearing cup installers (Ford 205-480 was especially useful when I had to improvise a puller for the inner pinion bearing), or turn your own on a lathe. I had all the tools I needed, but was missing some specialty tools I really wanted like " Ford 205-393 Installer, Drive Pinion Flange" and "Ford 205-072 Universal Flange Holding Wrench". I made this process slightly more annoying by not buying these.

Making setup bearings for the pinion setup would be a good call if using non-Spicer parts, but Spicer etches their gears to indicate how far off nominal they are. A decent first setup can be had if you use those numbers to inform pinion depth and carrier shim stacks... that's about all it took for me to get a good pattern.

I'd wager anyone who has done IFS diffs wouldn't have much trouble with these Ford differentials.

I wish I knew the stock Ranger ring gear was bolted on to the carrier before I got into it... I incorrectly assumed it was welded. Now, I wonder if these would fit this carrier: https://www.yukongear.com/shop/yg-dm190fd-488r.

I still have to do the rear, but that should be more straightforward.

P.S. - If anyone was paying attention to my musings on potentially using a Bronco M190 FDU with a Ranger intermediate tube on a Ranger, that won't work without at least a Bronco Driver side inner CV cup. The Bronco FDU casting is wider on that side and uses a longer CV stub shaft to reach the diff carrier splines... so goofy.

P.P.S. - I'm assuming my diff won't hold up to much violence with 37's, so I've started a years-long money saving effort for 40's, Atlas T-case, 3.5" internal bypass dampers, a cage, 934 CV's and Ford 9" front and rear. I want this truck to be a slightly more redneck analog to the RTR Fun-Runner Ranger someday:

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[TerraMechE]

The rear gears are done, and gosh, the truck feels a lot happier, especially the transmission.

Rear gears were also quite a bit more straightforward than the front. I love that Dana etches their pinion depth variance on the pinion; it makes setup so much easier.

Some may note from earlier photos that I installed an Eaton Truetrac. I had the stock locker in, but I've always really wanted to try a helical limited slip differential. I don't doubt I may end up putting the locker back in someday, but for now, I think the limited slip matches how I use the truck pretty well. I'll see, I guess.

Fun fact: the Truetrac offered is for non-locker Ranger axles. I had to buy new axle shafts to make it work. The locker axle shafts are different lengths side to side whereas the non-locker axle shafts are the exact same part for both left and right sides. Cool...

 

[TerraMechE]

Here's some more info if anyone is interested in further details (I just keep editing as I remember things):

Front Parts:
Dana Spicer 10130628 x1 - Differential Case Assembly and Gear Set (Bronco 4.46 pinion, welded ring gear and carrier)

Spicer 10267426 x1 - 21-22 Ford Bronco Differential Rebuild Kit (comes with bearings, shims, gasket maker and patterning paint)

Ford KB3Z4B416A x2 - Drive Axle Shaft Seal

Ford KB3Z3254B x1 - Differential Pinion Seal

Rear Parts:
Ford Performance M-4209-446 x1 - M220 rear axle ring and pinion gears, 4.46 ratio

Ford Performance M-4210-R x1 - M220 REAR END RING AND PINION INSTALLATION KIT

Optional parts I bought:

Eaton Truetrac 917A736 (I have the stock e-locker which is excellent, but always wanted to try a helical limited slip)

Ford KB3Z4234D x2 - these are rear axle shafts for the Rangers with open diffs, which I needed for the Truetrac. The Rangers with locking diffs have different length axles left to right. So, if you have a stock e-locker and want to keep it, don't worry about this at all. If you have an open diff, you'll need a new carrier like the welded ring gear Bronco open diff, truetrac, ARB, or Eaton e-locker, but you won't need new axleshafts. This is just for weirdos like me who want to delete their stock locker for a limited slip.

Tools:
General automotive tools: 1/2" impact, impact sockets (up to 32mm and 35mm), pry bars, dead blow hammer, ball peen hammer, 4+lb hammer, 250 ft-lb capable torque wrench, bearing separators/pullers, hydraulic press, punches, chisels, 3 jaw puller, a long 1" aluminum rod came in handy..., loctite, seal grease, gear oil, etc.

dial or beam style torque wrench for torque to rotate measurements, needs to be capable of reading between 5 to 40 in-lbs

Dial indicator with magnetic base

Calipers for measuring shim stacks

Ford Tools: 205-1024, 205-480, 205-488, 205-1058, 308-945, 205-1018, 205-1055, 205-126, 205-072, 205-208, 205-393

Note that I did not have all the specialty tools I listed, nor did I need all of them, but I wanted all of them at some point...

References:
Ford Ranger service manuals I found on Ranger5g.com

Jeep Wrangler JL Gear Swap | Spicer Parts

How to Re-Gear a Jeep Wrangler JL Dana 44 with ARB Install

Ultimate Toyota Tacoma Build Episode 4. 5.29 Yukon Gears And ARB Lockers.

Toyota Gear Install, IFS and Rear Drop Out How To

(I used Toyota ring and pinion installs as a reference just to see how clamshell diffs are done, in general)

M220 Rebuild Specs (Bronco/Ranger specs should come with the ring and pinion, see attached PDF, but these were about the same)

M186 Rebuild Specs (I could not really find anything in the way of backlash and torque to rotate specs for the M190 diff, so I measured those as I was disassembling the diff and found them to be in the ballpark of the Jeep M186 diff... highly dubious, but that's what I did)

Tips:
Dana Spicer pinion gears come with their thickness variance from nominal etched on the pinions. This makes calculating the needed pinion depth and associated shim stack so much easier than guess and check setup. If not using Dana parts, I'd recommend using and grinding down old bearings and races to a slip fit for use as setup bearings. This will help get close on backlash and pattern before committing to pressing in the new bearings.

The rear axle is relatively straightforward for a DIY. Regarding the front, if I were to do this again, I might just take the front differential / FDU out of the truck and take it to a shop that does Toyota IFS gears. The front clamshell is a bit of a pain unless you have the right tools for it.

Forscan or the Ford Performance ProCal tuner can change the tire size to get the speedo right. I also changed the gear ratio this way.

Oil:
I'm breaking in with Motorcraft 80w90 oil. After that, I'll be trying Redline 75w140NS ("NS" designates no friction modifiers) in the rear diff with the Truetrac (which seems to not want friction modifiers; they reduce the torque bias ratio of helical limited slips). The front diff will get the Redline 75w140NS mixed with Redline Heavy Shockproof. Why? I dunno... their marketing copy seemed convincing enough for me to be a willing sucker this go-round. Normally, I'm very much about sticking to Ford's oil specs, but I think 37's put me outside their design envelop and even Dana seems to want 75w140 in their axles. I do not have much confidence in the little front M190 standing up to 37s, if driven in anger. Figured I'd try and help it at least a little bit with the Shockproof oil, even as I feel this is likely a fool's errand.

Observations:
If a person has ever done a 2 stroke bottom end, replacing all the transmission bearings along with the crank, this job is about the same level of effort. Relative to 4 stroke or automotive engine builds... you'd have no trouble. That's my frame of reference.

With 37x12.5r17 Cooper AT3 XLTs @ 27 psi and 4.46 gears, 75mph happens at 2000rpm in 10th gear.

Shifts feel very good now, with little lag or flare between gears. I also have the FP tune and only run the transmission in sport mode.

It is very difficult to break in these gears with an easy going driving style... The truck wants to go fast.

I can't really experience the Truetrac properly until the gears are broken in, but it does change the handling dynamics of the truck. I think I like it.

 

[Colo_Ranger]

So... are you willing to help a fellow CO Ranger regear? I'd love to pick your brain but I can't message you.

 

[TerraMechE]

So... are you willing to help a fellow CO Ranger regear? I'd love to pick your brain but I can't message you.

No.

I've offered as much help as I'm willing and qualified to give. Being quite a hack, I'd be a terrible resource, anyways.

 

[Colo_Ranger]

No.

I've offered as much help as I'm willing and qualified to give. Being quite a hack, I'd be a terrible resource, anyways.

fair enough.

 

[TerraMechE]

fair enough.

I appreciate the understanding. I don't have time like I used to and so I tend to allocate it in stingier ways.

 

[Tremor-R]

I appreciate the understanding. I don't have time like I used to and so I tend to allocate it in stingier ways.

Here's some more info if anyone is interested in further details (I just keep editing as I remember things):

Front Parts:
Dana Spicer 10130628 x1 - Differential Case Assembly and Gear Set (Bronco 4.46 pinion, welded ring gear and carrier)

Spicer 10267426 x1 - 21-22 Ford Bronco Differential Rebuild Kit (comes with bearings, shims, gasket maker and patterning paint)

Ford KB3Z4B416A x2 - Drive Axle Shaft Seal

Ford KB3Z3254B x1 - Differential Pinion Seal

Rear Parts:
Ford Performance M-4209-446 x1 - M220 rear axle ring and pinion gears, 4.46 ratio

Ford Performance M-4210-R x1 - M220 REAR END RING AND PINION INSTALLATION KIT

Optional parts I bought:

Eaton Truetrac 917A736 (I have the stock e-locker which is excellent, but always wanted to try a helical limited slip)

Ford KB3Z4234D x2 - these are rear axle shafts for the Rangers with open diffs, which I needed for the Truetrac. The Rangers with locking diffs have different length axles left to right. So, if you have a stock e-locker and want to keep it, don't worry about this at all. If you have an open diff, you'll need a new carrier like the welded ring gear Bronco open diff, truetrac, ARB, or Eaton e-locker, but you won't need new axleshafts. This is just for weirdos like me who want to delete their stock locker for a limited slip.

Tools:
General automotive tools: 1/2" impact, impact sockets (up to 32mm and 35mm), pry bars, dead blow hammer, ball peen hammer, 4+lb hammer, 250 ft-lb capable torque wrench, bearing separators/pullers, hydraulic press, punches, chisels, 3 jaw puller, a long 1" aluminum rod came in handy..., loctite, seal grease, gear oil, etc.

dial or beam style torque wrench for torque to rotate measurements, needs to be capable of reading between 5 to 40 in-lbs

Dial indicator with magnetic base

Calipers for measuring shim stacks

Ford Tools: 205-1024, 205-480, 205-488, 205-1058, 308-945, 205-1018, 205-1055, 205-126, 205-072, 205-208, 205-393

Note that I did not have all the specialty tools I listed, nor did I need all of them, but I wanted all of them at some point...

References:
Ford Ranger service manuals I found on Ranger5g.com

Jeep Wrangler JL Gear Swap | Spicer Parts

How to Re-Gear a Jeep Wrangler JL Dana 44 with ARB Install

Ultimate Toyota Tacoma Build Episode 4. 5.29 Yukon Gears And ARB Lockers.

Toyota Gear Install, IFS and Rear Drop Out How To

(I used Toyota ring and pinion installs as a reference just to see how clamshell diffs are done, in general)

M220 Rebuild Specs (Bronco/Ranger specs should come with the ring and pinion, see attached PDF, but these were about the same)

M186 Rebuild Specs (I could not really find anything in the way of backlash and torque to rotate specs for the M190 diff, so I measured those as I was disassembling the diff and found them to be in the ballpark of the Jeep M186 diff... highly dubious, but that's what I did)

Tips:
Dana Spicer pinion gears come with their thickness variance from nominal etched on the pinions. This makes calculating the needed pinion depth and associated shim stack so much easier than guess and check setup. If not using Dana parts, I'd recommend using and grinding down old bearings and races to a slip fit for use as setup bearings. This will help get close on backlash and pattern before committing to pressing in the new bearings.

The rear axle is relatively straightforward for a DIY. Regarding the front, if I were to do this again, I might just take the front differential / FDU out of the truck and take it to a shop that does Toyota IFS gears. The front clamshell is a bit of a pain unless you have the right tools for it.

Forscan or the Ford Performance ProCal tuner can change the tire size to get the speedo right. I also changed the gear ratio this way.

Oil:
I'm breaking in with Motorcraft 80w90 oil. After that, I'll be trying Redline 75w140NS ("NS" designates no friction modifiers) in the rear diff with the Truetrac (which seems to not want friction modifiers; they reduce the torque bias ratio of helical limited slips). The front diff will get the Redline 75w140NS mixed with Redline Heavy Shockproof. Why? I dunno... their marketing copy seemed convincing enough for me to be a willing sucker this go-round. Normally, I'm very much about sticking to Ford's oil specs, but I think 37's put me outside their design envelop and even Dana seems to want 75w140 in their axles. I do not have much confidence in the little front M190 standing up to 37s, if driven in anger. Figured I'd try and help it at least a little bit with the Shockproof oil, even as I feel this is likely a fool's errand.

Observations:
If a person has ever done a 2 stroke bottom end, replacing all the transmission bearings along with the crank, this job is about the same level of effort. Relative to 4 stroke or automotive engine builds... you'd have no trouble. That's my frame of reference.

With 37x12.5r17 Cooper AT3 XLTs @ 27 psi and 4.46 gears, 75mph happens at 2000rpm in 10th gear.

Shifts feel very good now, with little lag or flare between gears. I also have the FP tune and only run the transmission in sport mode.

It is very difficult to break in these gears with an easy going driving style... The truck wants to go fast.

I can't really experience the Truetrac properly until the gears are broken in, but it does change the handling dynamics of the truck. I think I like it.

Great job Terra, thanks for the write up! Coincidentally, I just ordered the Bronco (MB3Z4141B) M190 with 4.46's and the E-Locker from Lakeland Ford, and matching Yukon gears/rebuild kit for the rear a day before reading this. I'm running 34's currently and the truck accelerates like a turd rolling up hill. I'm most anxious however to see how the front locker portion of this experiment is going to work out.... will post any relevant info when finished. Again, thanks for sharing!

 

[Colo_Ranger]

Great job Terra, thanks for the write up! Coincidentally, I just ordered the Bronco (MB3Z4141B) M190 with 4.46's and the E-Locker from Lakeland Ford, and matching Yukon gears/rebuild kit for the rear a day before reading this. I'm running 34's currently and the truck accelerates like a turd rolling up hill. I'm most anxious however to see how the front locker portion of this experiment is going to work out.... will post any relevant info when finished. Again, thanks for sharing!

How are you handling the different mount point in the passengers side?

 

[TerraMechE]

I've had this setup out just a bit more and have had some time to reflect. Keep in mind I favor going fast-ish on dirt and only like milder rock-crawly situations.

Thoughts on 37s:

- Big tires rule, everything in the way of them gets smaller
- They get the stock brakes HOT rallying around twisty dirt roads, especially in left-foot braking situations
- I've never been more aware of my tie rods, steering inputs are made with much mechanical sympathy when crawling through rocks
- 4.46 gears work with these lightweight Coopers for the most part, but I'd probably just jump to 5.13s if I had this to do over


Thoughts on the Truetrac:

- it is not a locker; it is not really an option for hardcore crawling
- e-brake can make it act almost like a locker, to a limited degree; it works better in this way with more suspension articulation than not
- I love the way it makes the truck handle at any speed above a crawl!
- for me, a Dana "Ultimate" FDU with a front locker could probably be a great compromise to allow me to have a broad offroad performance envelope


Other thoughts:

- I need to revalve the suspension again, as the capability goes up with the tires, I find myself wanting more damping on faster trails... It's so fun

 

[Colo_Ranger]

Now that you've had a chance to flex out, do you have clearance issues with the 37s? Rubbing issues, etc.

 

[awd.nv]

Thanks for all the shared info in here!

 

[TerraMechE]

Now that you've had a chance to flex out, do you have clearance issues with the 37s? Rubbing issues, etc.

Oh yeah I have clearance issues!

On the front, I cut and hammered back the inner fender weld seam at the back of the fender well. I also had to limit bump travel about an inch. It cycles about 10" really cleanly right now, even with full steering lock.

On the rear, with the spring under suspension, and Raptor bump stops allowing more travel, I had to relocate the fuel return and vent lines a bit. I cut a bit back there, too. It rubs the middle of the inner fender well at full rear flex. I don't want to limit bump travel in the rear, so that's gonna require some cutting and welding on the bed.

I actually got a beater for commuting so I could mess with this thing more. This truck will never be done...

Front wheel well hacking:

 

[Colo_Ranger]

Pretty much what I expected to have to do on mine, if (when) I jump to 37s. I think next year will be 35s (up from 34). A true 35 looks killer on these trucks.

 

[Sross975]

Can you share more pictures on the cut fenders? Any advice? I like the look and want to do it on my truck. Was thinking of making my own liners for it as well.

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