Sailsbury Diff removal.

It's a matter of a few thou, but it's what puts the preload on the main carrier bearings so it's fairly vital.

And the design works bloody well in terms of being strong - I've yet to smash a salisbury pattern diff without being incredibly stupid (silly amounts of horsepower and serious abuse of the vehicle), but have had some interesting failures with banjo style diffs whilst being relatively sensible in the same vehicle.

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EMB
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The stretching is NOT to get it OUT its to load the bearings properly - which is why its so bloody tough. The MAXIMUM deflection permissible is only 15 thou.

Steve

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steve

And look at the physical size difference, of course the tractor ones don't break! If they were smaller due to the physical space constraints of the design, they'd need to be made to a better, tougher design to be reliable long-term. As it stands, they have more space available and also they don't rotate anything like the same speeds, which as long as cleanliness is observed, increases the lifespan considerably. Gimme enough space physically and I could design a diff that would handle

4,000,000 bhp reliably from basic materials (no fancy metallurgy), but ask me to design it to fit in a certain space, I'd fall flat on my face! The Salisbury (Dana) type of diff mounting has been around for years, it is a good, strong and well-proven design that has been used in many forms by many vehicle manufacturers. It was designed by people (engineers) that knew what they were doing, not by people who merely thought they new what they were doing. Anyone who grinds clearance into a salisbury case is going to suffer premature bearing failure and possibly lunch their diff, it is designed to run with a certain preload, no preload = imminent failure! Badger.
Reply to
Badger

On or around Sat, 01 Jul 2006 16:38:01 +0100, steve enlightened us thusly:

ah. Mind, I'd have thought you could load the bearings by other means - other diffs do. The strength of the diff is in how it's designed, mostly, not in the axle casing. Older rover diffs were not designed to take all that much power and/or torque, so if you overload them with a big engine they tend to fail. That's not an inherent design fault, simply that the diff was designed for a give power. The Dana ones are obviously designed for more power, but if LR set out now to design the rover-type axle, then the diff and half-shafts would be designed to take the load of the current engines.

Reply to
Austin Shackles

On or around Sat, 1 Jul 2006 17:37:25 +0100, "Badger" enlightened us thusly:

OK, I accept that now that I know about it.

doesn't mean that it has to be done that way. There are plenty of other diffs which are not like the dana ones.

Reply to
Austin Shackles

Oh but they sometimes do.

If they were smaller due to the physical space constraints of the

I have no figures available but the front axles diffs are very compact, and so are the rear ones considering the extreme duty they are subject to. The front diffs are certainly more compact that the Salisbury and they probably turn as fast or faster, the axles having epicyclic reducer gears on the half-shafts as a rule to reduce the torque to which the diff is subject.

Yes, it is an old design and it is generally reliable, but it is not unique in being reliable.

Huw

Reply to
Huw

You've hit the nail on the head. Even Dana make axles that don't need case stretching and they are perfectly good and reliable. Case stretching is NOT a pre-requisite for reliable diffs and just one look at the Salisbury shows that it does not have a particularly compact differential.

Huw

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Huw

Very true, there are a lot of good designs out there, unfortunately some of the diffs that get labelled as bad ones are usually labelled thus due to failure after they were subjected to higher power/torque loadings than the manufacturer intended, as has already been said by your good self I think, further up the thread. Series jag XJ's used a slisbury differential unit, a lot smaller than a landrover one (I think the jag one was the 4HU and the landy is the 8HA?) yet it could reputedly handle 1000bhp. Bet if you put it in something as heavy as a landy it'd go bang long before that figure was reached. Lighter vehicles will spin a wheel at a lower torque figure, thus unloading the transmission. Badger.

Reply to
Badger

I was referring to your comment about tractor diffs being reliable, I didn't mean that they never, ever break. They probably suffer less failures than landrover ones though?

Right, I see. I must admit to not having a great knowledge of 4wd tractors, my involvement with tractors stopped (thankfully!) with the MF135 / International 474! I cut my teeth doing clutch changes on Majors and Dexta's!! My comments were directed towards the rear axles, I should have made that clear. I understand your comments re. higher speed and lower torque by using the epicyclic reduction, it's quite possible that they had to be designed that way to be compact enough to physically fit the application? Another consideration has to be NVH (noise, vibration and harshness), on a tractor you can design the diff helix angles etc of the gears for maximum strength, automotive design tends to be a compromise of strength v's NVH, even on landrovers!

Absolutely. I can think of lots of makes of vehicles with very reliable diff units, BMW and Merc spring to mind, even Ford granada/sierra ones are pretty reliable if kept within their design criteria for power handling. Badger.

Reply to
Badger

In message , Huw writes

I think the Salisbury axle on the back of Land rovers is a Dana 60. American dragster folk love it because it doesn't break. Some dana axles don't have to be preloaded and these tend to be swapped in favour of

60's. They must have something going for them..
Reply to
mark

On or around Sun, 2 Jul 2006 06:45:43 +0100, mark enlightened us thusly:

It's undoubtedly a good axle. point is that you don't have to make one like that to make a good one.

Reply to
Austin Shackles

Much like Toyota have done with their Hilux diffs - similar design and size to the Rover unit but a heap stronger - I'm successfully running

550BHP (and LOTS of torque) through one in my race car and have broken 2 half shafts in 5 years. When I get a supply of tuits I'll have a go at marrying one into a LR diff housing.
Reply to
EMB

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