Author Topic: 2017 F-450 Dana M300 Limited Slip Differential  (Read 6961 times)

Offline TankEngine

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2017 F-450 Dana M300 Limited Slip Differential
« on: May 04, 2017, 07:36:42 PM »
So I'm considering getting a 2017 Ford F-450. But, I've been able to find very limited information about the dana m300 rear axle that ford is using in the 2017 dually f350, f450 and f550. If you jump to "Rear Axle Specifications " on this spec sheet, it says that on the 6.7L engines the dana m300 is a "2 ­pinion with limited ­slip." I am wondering what kind of limited slip differential this is. According to this video by Filthy Motorsports, those limited slip differentials which use springs wear out and become open differentials after about 20,000 miles, whereas those with all-gear designs last the life of a truck. Is the "2 pinion limited slip" differential in the dana m300 an all-gears design, or does it have springs that will wear out over time? Will it fully lock the differential in low traction situations? Should I consider swapping the F450's limited slip differential for a true locker, and if so where should I be looking for such?

Offline ncjeeper

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #1 on: May 05, 2017, 01:12:34 AM »
Just a guess here but I would think the limited slip will have a clutch pack in it. If so the clutches will were out over time. I have rebuilt older units of this type. You should get over 100,000 miles on one before needing a rebuild. For everyday street use I would stick with some type of limited slip unit. A full time locker doesn't have very good street manners because it keeps both wheels turning at the same rate. It will make noise when it has to disengage to allow the wheels to turn differently(which can be a little unsettling) and your tire wear will increase.

Offline Davew223

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #2 on: May 05, 2017, 12:49:00 PM »
What ncjeeper said

Offline machinisttx

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #3 on: May 07, 2017, 08:23:58 PM »
All of the limited slips I know of use clutch packs. I didn't do much searching, but I suspect that somewhere on the Dana-Spicer website there is a exploded drawing/tech sheets/etc. that would tell you for sure. Lots of people don't like limited slips, with good reason....seldom do they work correctly. Any of them will eventually wear out, and most of the clutch pack types require a specific additive to the differential oil. No limited slip "locks" the two axleshafts together, period. At best, they "sort of" keep it from being a one wheel wonder.

Lockers will mechanically lock both axleshafts to turn at the same speed, but that should only occur when you're on the throttle. Off the throttle, cornering should not be a problem. A spool would physically lock both axleshafts together all the time.

Talk to a supplier of offroad axle parts/differentials and find out if a selectable locker is available yet for the M300. A non-selectable locker may be available as a factory option...or they might not be available at all yet. Based on the searching I just did, I'm going to say there aren't any aftermarket options available yet.

Why are you worried about this?

Offline TankEngine

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #4 on: May 07, 2017, 09:31:02 PM »
What I'm basically looking for is a dually that will perform reasonably well off-road. Not looking for a rock crawler, just something that can handle bad fire roads and mud. I want it to be a dually because I will be hauling a slide-in camper for boondocking, and when I eventually buy land this truck will be used to haul heavy trailers.

I prefer to stick with Ford because I can get special Z plan pricing. But the lack of a locking differential on Ford's duallys has me looking elsewhere. GM trucks offer a "locking differential" which I know is an Eaton G80, whereas Dodge trucks offer an "anti-spin" differential which I heard is also an Eaton G80. Is it true that dodge uses the Eaton G80, and if so how is its performance in low traction situations? Does the Eaton G80 compare to, say, an ARB locking differential?

Offline machinisttx

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #5 on: May 08, 2017, 08:17:48 PM »
The eaton is an automatic locker while the ARB is selectable on/off. In operation, both are functionally identical. The only downside to the ARB is that it depends on compressed air to keep it activated. If your air lines/fittings/compressor fail, you're back to an open differential. ARB's are also probably about twice as much, possibly a little more, in cost over an automatic locker. I have no idea what Chrysler/Dodge uses, but I will ask my cousin(works at a stealership, fleet sales now I think) and see what he knows. GM used Detroit Lockers in the past, it appears that Eaton is their choice now. http://www.eaton.com/Eaton/ProductsServices/Vehicle/Differentials/mlocker/index.htm

Having a factory locker option would be a whole lot cheaper, but nothing says you can't have an aftermarket unit put in. It's going to cost a lot more if you have to go aftermarket though. The main problem at present with the M300 is that nothing is currently available. It will probably take a year at least before one of the well known names introduces something.

You might try asking over on pirate4x4 or expeditionportal. Someone over there might know more.

Offline TankEngine

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #6 on: May 09, 2017, 09:55:04 PM »
Machinisttx, thanks for offering to talk to your cousin about this. I'd be real interested to hear what he has to say. The Eaton G80 sounds better than the selectable lockers if it does the same thing without having the extra cost/labor and without having to flip a switch. I will post threads elsewhere about the time this thread is done.

Offline CPT Morgan

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #7 on: May 13, 2017, 10:10:21 PM »
Can't help you on the mechanics of it all but have had extensive experience with trucks hauling heavy loads.  Have never used a dually but normally run with 12-ply tires.  Have ran everything from heavy campers to hauling heavy trailers all over the country, including  stock trailers full of cattle and flats beds hauling tractors, as well as 5 ton of hay at a time.....  I wouldn't spend the extra up-front cos and extra maintenance cost on the dually.

Offline xxdabroxx

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #8 on: May 23, 2017, 10:42:19 AM »
I've never really been a big fan of the G80, around here they say the G stands for grenade.  It's better than nothing, but I would rather have a truetrack.  For the use you describe, I think either the G80 or the clutch pack limited slip would be fine. 

Offline machinisttx

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #9 on: June 03, 2017, 10:28:22 PM »
I haven't forgotten about this, just haven't had a chance to get in touch with my cousin. Keep meaning to get down to his house, but stuff keeps coming up. Feeling all wonderful with an upper respiratory/ear infection right now.  :-\

The trac lok LSD that was in my jeep's dana 35 worked pretty well, but it definitely was not a locker.

Offline ncjeeper

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #10 on: June 04, 2017, 12:39:47 AM »
The trac lok LSD that was in my jeep's dana 35 worked pretty well, but it definitely was not a locker.
That limited slip probably kept that 35 alive.

Offline machinisttx

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Re: 2017 F-450 Dana M300 Limited Slip Differential
« Reply #11 on: June 21, 2017, 06:26:04 PM »
I don't think the presence, or lack thereof, of a LS differential made any difference whatsoever in it's demise. The dana 35 is a craptacular axlehousing. I've never gotten around to performing an autopsy, but I suspect I'll find bad teeth on the ring/pinion. Sure felt like it skipped a few teeth.


Finally got together with my cousin and asked him about the traction adding options available from Dodge. He said that all he's aware of is a limited slip(probably the trac-lok, which is a Dana product) on trucks up to 1 ton. He also said he didn't remember even seeing that option on cab and chassis models or the 4500 and 5500 trucks...but he's going to look and find out for sure.