New 32 spline Dana 44 Front Drive Unit and axle upgrade will be available from Dana Spicer for bigger tires

[goatman2]

This is pretty interesting.

https://spicerparts.com/parts/axle/performance/ford-bronco/front-drive-axles

Spicer is offering a complete front differential (front drive unit) with gear ratio choice and factory E-locker as an upgrade from the factory locked M210. Looks like it will be an M220 ring and pinion with 32 spline CV axles. Same 32 spline and gear size as the M220 rear. This is a good upgrade from the 29 spline CV axles with the stock M210 when equipped with a front locker. Wonder how much the FDU and axles will cost. We still don't know how much the 29 spline M210 will take with bigger tires and rock crawling, but at least there is an option.

Experience in Jeeps and other vehicles shows that 29 spline axles can have trouble handling 37's or larger with harder core rock crawling. Still much to learn on these vehicles, but nice to see plenty of stronger product being offered already. RCV already has 29 spline 300M CV axles for the front, which should be pretty tough. Interesting that they went ahead and just made them from 300M instead of offering 4340 and 300M as an option.

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[LHD]

This is pretty interesting.

https://spicerparts.com/parts/axle/performance/ford-bronco/front-drive-axles

Spicer is offering a complete front differential (front drive unit) with gear ratio choice and factory E-locker as an upgrade from the factory locked M210. Looks like it will be an M220 ring and pinion with 32 spline CV axles. Same 32 spline and gear size as the M220 rear. This is a good upgrade from the 29 spline CV axles with the stock M210 when equipped with a front locker. Wonder how much the FDU and axles will cost. We still don't know how much the 29 spline M210 will take with bigger tires and rock crawling, but at least there is an option.

Experience in Jeeps and other vehicles shows that 29 spline axles can have trouble handling 37's or larger with harder core rock crawling. Still much to learn on these vehicles, but nice to see plenty of stronger product being offered already. RCV already has 29 spline 300M CV axles for the front, which should be pretty tough. Interesting that they went ahead and just made them from 300M instead of offering 4340 and 300M as an option.

Offered in ratios that do not match the factory diffs. 4.56 v 4.46. Who’s idea was that? I would love to upgrade the front with an e-locker to match the rear ratio on my base without having to doing the rear.

 

[flip]

Interesting. We have heavy truck parts through Daimler which includes Spicer. Wonder when these become available if we can get them through normal channels.

 

[goatman2]

Offered in ratios that do not match the factory diffs. 4.56 v 4.46. Who’s idea was that? I would love to upgrade the front with an e-locker to match the rear ratio on my base without having to doing the rear.

Didn't notice that. Yep, no 4.27 or 4.46. Spicer also offers a bolt in Dana60 for the rear, so looks like they are matching ratios with the D60, and of course ring and pinions of all ratios are already on the dealer accessory price list. No 4.46, guess they figure if you're going hard core you'll have an automatic. j/k

I do think that 4.46 and 4.56 is close enough that in nearly all situations it wouldn't matter. Only time would be like on slickrock in Moab, and much of the time there you can run 2wd anyway. And, since it is a 4.46 gear it isn't Sasquatch so no lockers, and that slight difference with open diffs would also work fine. Any time the vehicle is turning in 4wd the tires are scuffing a bit anyway.

 

[MaverickMan]

Didn't notice that. Yep, no 4.27 or 4.46. Spicer also offers a bolt in Dana60 for the rear, so looks like they are matching ratios with the D60, and of course ring and pinions of all ratios are already on the dealer accessory price list. No 4.46, guess they figure if you're going hard core you'll have an automatic. j/k

I do think that 4.46 and 4.56 is close enough that in nearly all situations it wouldn't matter. Only time would be like on slickrock in Moab, and much of the time there you can run 2wd anyway. And, since it is a 4.46 gear it isn't Sasquatch so no lockers, and that slight difference with open diffs would also work fine. Any time the vehicle is turning in 4wd the tires are scuffing a bit anyway.

No its too far, it will break... something.

 

[goatman2]

No its too far, it will break... something.

I respectfully disagree. In 4wd on trails any time the vehicle is turning there is scrub, and the parts can handle it. It's not a strength issue, but it will keep the drivetrain bound up constantly on rock surfaces, but that happens anyway just from slight turns. When combining 9" diffs with Dana diffs it is common to have slight differences in gear ratios front to rear as all the available ratios don't match. It's a 2% difference, how often on a trail is there a 2% difference between what the front is going over relative to the rear, or a 2% difference in scrub due to turning. Of course, it's not ideal, but based on my experience and what I've seen my opinion is that it would not be a problem. Not ideal, but if budget is an issue, worth a shot. Really, if going to bigger tires where the stronger front diff is desired, the reality is that lowers gears should be done anyway which would include regearing the rear diff.

BTW, I have two different friends who had Jeeps with totally different ratios front and back, because the shops that did the gears screwed up (4.88/4.56). Both wheeled for a while before figuring out something was wrong. Amazing.

BTW, just talking here. While I think it would work, I wouldn't do it myself, I'd regear to a lower ratio.

 

[MaverickMan]

I respectfully disagree. In 4wd on trails any time the vehicle is turning there is scrub, and the parts can handle it. It's not a strength issue, but it will keep the drivetrain bound up constantly on rock surfaces, but that happens anyway just from slight turns. When combining 9" diffs with Dana diffs it is common to have slight differences in gear ratios front to rear as all the available ratios don't match. It's a 2% difference, how often on a trail is there a 2% difference between what the front is going over relative to the rear, or a 2% difference in scrub due to turning. Of course, it's not ideal, but based on my experience and what I've seen my opinion is that it would not be a problem. Not ideal, but if budget is an issue, worth a shot. Really, if going to bigger tires where the stronger front diff is desired, the reality is that lowers gears should be done anyway which would include regearing the rear diff.

BTW, I have two different friends who had Jeeps with totally different ratios front and back, because the shops that did the gears screwed up (4.88/4.56). Both wheeled for a while before figuring out something was wrong. Amazing.

BTW, just talking here. While I think it would work, I wouldn't do it myself, I'd regear to a lower ratio.

I wouldnt do it. I have had bind with just different brand or wear of tires before. Maybe it will last a month or years depending on use, but one day it will fail. And the person will be lucky if it isnt a cracked transfer case or diff housing. Personally I have always wanted to match gears for diff sized tires for that hotrod look. Jeep did it on a concept and tractors do it. But its risky.

 

[Rocketeer Rick]

I once watched a BITD class 7300 Ranger run an event with 4.56 front gears and 4.88 rears (because they couldn't get the 4.88s for the front at the time). Over the course of the event, the mismatch had the effect of winding up the front drivetrain like a giant torsion spring while in 4WD. It got to the point where it started affecting the steering response. They thought the steering rack needed replacing.

When they pulled into the pit and lifted the truck up, the whole front end went sproing and tires snapped around. Once it unloaded, the steering went back to normal, and they took off again. Basically, the front was trying to run faster than the rear and couldn't, which had the effect of becoming a brake, forcing negative torque into the front end of the truck.

In this case, the ratios are switched around, but the effect would be similar. I think that it would wind up the front end until its disconnected, though that might make that more difficult. But the repeat occurrence of it will eventually fatigue the system. Something will eventually fail but it might be a soft failure, and it might take years.

Anyway, it seems like Dana is happy to continue to use their standard ratios for aftermarket models. But I'd bet that the ratios they make for Ford (which seem like an unique series for Ford) are tooled up with money from Ford, so Dana can only make them for Ford. But on the plus side, they get to sell you another set of gears for the rear so you can regear that axle to match what they sell for the front...

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