limited slip front diff use in snow and ice/ throttle contrl

[E350]

Thanks for reporting back. Keep your comments coming.

[TwoVans]

Finally got a chance to get my van into snow in CO. Got to go slow through snow about 6-12 inches deep up a very long drive. Also got to try using it at highway speeds on a snow-covered I-70.

Both scenerios worked flawlessly with excellent manners. Highly recomend Detroit Truetrac for front axle!

[JoeH]

Originally Posted by TwoVans

Finally got a chance to get my van into snow in CO. Got to go slow through snow about 6-12 inches deep up a very long drive. Also got to try using it at highway speeds on a snow-covered I-70.

Both scenerios worked flawlessly with excellent manners. Highly recomend Detroit Truetrac for front axle!

I've been less that impressed with an open diff in the front on snowy and icy roads. I've been devouring the axle threads here and in the truck forums as well as bugging Ujoint Chris and I'm convinced on replacing the open diff in the front with a TrueTrac rather than a full locker up front. That way, the tires can move at different speeds and your not fighting the steering every time you're in 4wd. Conversely some SMB aficionados seem to prefer a locker in the front to pull the load rather than push but I'm decided on limited slip for the front.

However, does anybody have any input for snow and ice with an open differential rather than limited slip on the rear axle? I'm planning to upgrade my semi-float to a FF D60 and am trying to decide between the OEM limited slip in the rear, a TrueTrac similar to the front and TwoVans application, or a selectable locker like the ARB. I'm not sure the TruTrac will fit in a D60 but the ARB locker will for sure. I'm not entirely certain I will like being fully locked in slippery conditions and the possibility of more rear end slide-out that what you might get with a limited slip. Or, with any possibility of slippery conditions do you just run with the lockers on and it's a non-issue?

I thought I'd ask in this thread rather than posting yet another axle conversion thread because I'm manly concerned about snow and ice and there is some great info in here.

[carringb]

I would go Tru-Track rear. By they time you add extra clutches to the stock limited slip to make it actually work, you risk blowing apart the carrier.

ARB lockers seems to a little maintenance needy. Eventually, it will leak. Plus, then you have an on-board air system, which is just another point of failure.

[JoeH]

Originally Posted by carringb

I would go Tru-Track rear. By they time you add extra clutches to the stock limited slip to make it actually work, you risk blowing apart the carrier.

ARB lockers seems to a little maintenance needy. Eventually, it will leak. Plus, then you have an on-board air system, which is just another point of failure.

Nice pic

I didn't know you could use an ARB with anything but an open differential? I confess, I was partly interested in an ARB because the PO installed on-board air which I never use. But was also under the impression that a True Trac wouldn't fit in the carrier on a FF D60 with the smaller ring gear than a D70 or Dynatrac Prorock60.

[arctictraveller]

Originally Posted by carringb

I would go Tru-Track rear. By they time you add extra clutches to the stock limited slip to make it actually work, you risk blowing apart the carrier.

ARB lockers seems to a little maintenance needy. Eventually, it will leak. Plus, then you have an on-board air system, which is just another point of failure.

That's a scary photo. Sadly, my rebuilt stock limited slip that has only a couple thousand miles on it is now making wicked bad noises. It was fine until I started four wheeling last week. Now, when I make a turn, it groans and shudders enough to shake the van. Randys ring and pinion who did all the work (new gears, rebuilt rear l/s, new l/s in front) can only recomend adding more additive. Meanwhile, I wont settle for less than pulling the cover for a full inspection. Being thousands of miles from home with lots more four wheeling in remote places is no where to have a busted diff. I'll report back when I know.

[carringb]

Correct on the ARB. It requires an open diff.

TruTrac fits the D60. The problem is it comes in 30 or 35 spline, not 32 spline which the E250/350 vans have. Napa sells 35-spline axle shafts, or you could pull some from an '07+ E150.

[rallypanam]

Originally Posted by arctictraveller

Now, when I make a turn, it groans and shudders enough to shake the van.

That doesn't sound good.

[E350]

ArcticTraveller: My guess is that you can't get better than Randy's Ring and Pinion for a rebuild.

When my limited slip E350 semi-floating rear differential was rebuilt by another company, I had the same problem - and got the same advice. So I did what they said and added another half or whole container (ounces) of the special limited slip additive and the shudder went away! And so did the function of the limited slip.

That is why, I personally, don't believe in the magic of limited slip. And although I have no personal experience with an ARB air locker (and don't deny carringb's warnings that it creates additional weak links and maintenance points) would like to eventually go with ARB air lockers front and rear.

JoeH: Personally, I prefer driving in 4x4 high with front hubs locked but with open differentials on snowy and icy roads. I think I have driven at least a few thousands of miles on snowy an icy roads, hmmm... yes I can say at least that. As I have previously posted I have also had a short wheelbase vehicle with an aggressive limited slip in the rear which even in 4x4 scared the crap out of me on snowplowed scraped down to ice roads because it would cause the vehicle to fishtail as it "automatically" grabbed better on one side and then on the other. The solution is to add more limited slip additive thereby reducing or losing the limited slip function.

This is how I would have people think about it (and then get input from others - Albertans for instance? The guy drives on frozen lakes for heaven's sake!): We drive in the Summer on dry sand-free roadways with an open differentials front and back at sometimes high speeds because IMHO an open differential is the most forgiving most predictable differential there is.

So, why wouldn't you also want that forgiving and predictable open differential when you are driving on snow and especially ice?

Add 4x4 and you've got the best of both worlds in my opinion.

Add a selectable locker (like an ARB which apparently will engage without the vehicle moving) and you also have a better chance of not being stuck on a plow berm half way into the hwy and the other half in the driveway when trying to get out after a big snow storm, or leaving an unplowed parking lot after a big snow storm - in other words, slow speed high traction needed conditions. But remember I have never owned an ARB or any other selectable locker (but I could've put one in for the price of the rebuild of my OEM limited slip rear differential...)

And no I don't think I would use the locker on snowy and icy roads at highway or even reduced highway speeds. But others would have to chime in here. Let's put it this way: driving on snow and ice is kinda like skiing with your car. You have a little bit of traction - which is enough if you drive slow enough for the conditions - but speed is the key and you must moderate your speed for the conditions. No open differential, no selectable locker, no limited slip differential can create additional traction. Only snow tires with studs will create additional traction, and then only up to a point.

There is a reason that 80KPH is the maximum speed on most BC rural highways (50 MPH). And that is in the Summer time.

[JoeH]

Originally Posted by carringb

Correct on the ARB. It requires an open diff.

TruTrac fits the D60. The problem is it comes in 30 or 35 spline, not 32 spline which the E250/350 vans have. Napa sells 35-spline axle shafts, or you could pull some from an '07+ E150.

I was planning on getting new axle shafts to make it 35 spline anyway. Bam, from what I understand a bolt in swap, same bolt pattern/etc and I can use my same 16" wheels. The rear driveshaft may need a new flange and length change though.

I think I'll pass on the OEM limited slip but am undecided on the Truetrac or ARB. I like the idea of having the locker for climbing walls in a top-heavy van but the main question is how do folks that have a selectable locker on the rear like having an open differential? That is, on a snowy or icy road would you just use the locker full time and does that work or is it terrifying?