Thread: Land Rover Diffs

Originally Posted by Bush65

I can't remember the spline count for H233 front or rear centre, I remember the rear axle is larger than the front, also front axle dia is similar to Toyota, but higher spline count because they a smaller/finer on Nissan.

Made from good material, most here would not break axles of the dia and sline of stock H233 rear axles in a rover - IMHO 35 spline would be overkill for more work and $$$$.

Thanks John. Im pulling 31 spline from somewhere but could be very wrong??? The axle itself would not cost more to make, but I guess the side gears would be custom, so may as well stick with the stock side gears. Axle length would be specific to the Rover for it to be drop in bolt in easy engineerable etc.

Am I correct in saying that the down side to the Nissan front is the small dia that the bearings etc represent, so there fore the biggest axle dia that can be used. I think I have read that the Toy front can be made bigger in axle shaft and bearing department???

I have seen one of the Nissan axles on a H260 break.
It was being abused at the time though

Originally Posted by Bush65

I can't remember the spline count for H233 front or rear centre, I remember the rear axle is larger than the front, also front axle dia is similar to Toyota, but higher spline count because they a smaller/finer on Nissan.

Made from good material, most here would not break axles of the dia and sline of stock H233 rear axles in a rover - IMHO 35 spline would be overkill for more work and $$$$.

Originally Posted by uninformed

Thanks John. Im pulling 31 spline from somewhere but could be very wrong??? The axle itself would not cost more to make, but I guess the side gears would be custom, so may as well stick with the stock side gears. Axle length would be specific to the Rover for it to be drop in bolt in easy engineerable etc.

Am I correct in saying that the down side to the Nissan front is the small dia that the bearings etc represent, so there fore the biggest axle dia that can be used. I think I have read that the Toy front can be made bigger in axle shaft and bearing department???

I had to go and check the info ARB list for airlockers and axle details:
Nissan H233B front, 31 spline, 32mm (1.26") dia
Nissan H233B rear, 33 spline, 33.3mm (1.31") dia
Nissan H260, 37 spline, 38.4mm (1.51") dia
Nissan H260 (full floater), 34 spline, 34.8mm (1.37") dia
Land Cruiser front and rear, 30 spline, 33mm (1.31") dia
Land Cruiser rear (1998 on) 32 spline, 34.8mm (1.37") dia
Land Rover 24 spline, 31.5mm, (1.24") dia

I had mistakenly thought the H233B rear (low pinion) had larger axles than that. They are larger than the front H233B (high pinion), but not by as much as I thought.

Many years ago I made up some axles for my bushie using a Nissan H233B front diff (31 spl, 32mm axles) and Land Cruiser 105 series rear diff (32 spl, 34.8mm axles). I still have these and hope to put them under my 120 landie if QLD change to national code of practice as they say.

From axle comments that often come up, it appears many people don't fully understand the issues of:

• strength and life
• static and dynamic loads

They typically say something like:

• I've never broken an axle (cv, or diff)
• It broke just driving steadily along the road
• etc

High static breaking strength (proved by test or simple calculation) doesn't necessarily translate to long life if the axle has bad stress raisers (stress raisers affect fatigue, not static strength). Nor does it necessarily translate to high strength under dynamic loads if poorly designed. Material (steel) properties also influence this - for same strength some materials are better for absorbing impact energy (Izod test).

The formulae for torsional strength used in a post above (and from memory by Mal Storey back when he compiled a list comparing Land Rover axles) was derived way back in our history and should never be used for designing shafts - it is ok to show why diameter makes a difference though. In most countries MSS (maximum shear stress) theory is used for shaft design e.g. in USA the ASME shaft design. The Australian Standard for Design of Rotating Shafts is possibly the most advanced of them all, but can be conservative.

Thanks again John. If the info from Mal Storey you are reffering to was posted on Outerlimits, then that is the info I posted from a sheet Mal gave me with info on his shafts, rover sizes and approx UTS given the material used and heat treatment. As far as design, well his shafts were determined bt LR themselves for major dia and spline. The waisting etc was his.....

The Nissan H233b front is definitley let down by its axle shaft size. Would this be due to what pinion it is (high or low) and the forces the diff and CV's could see in real world use???

Was you front a hybrid? what was what???

what are your thoughts on gun boring shafts for better shock absorbsion? Im guessing they would not have as high UTS as a solid of same root dia, same outer profile, same material/heat treatmeny???

Originally Posted by uninformed

Thanks again John. If the info from Mal Storey you are reffering to was posted on Outerlimits, then that is the info I posted from a sheet Mal gave me with info on his shafts, rover sizes and approx UTS given the material used and heat treatment. As far as design, well his shafts were determined bt LR themselves for major dia and spline. The waisting etc was his.....

The Nissan H233b front is definitley let down by its axle shaft size. Would this be due to what pinion it is (high or low) and the forces the diff and CV's could see in real world use???

Was you front a hybrid? what was what???

what are your thoughts on gun boring shafts for better shock absorbsion? Im guessing they would not have as high UTS as a solid of same root dia, same outer profile, same material/heat treatmeny???

Some axle (half shaft) spline details (number of teeth and outside diameter, from ARB Airlocker application chart) by make:

Land Rover and Salisbury,
24 tooth spl, 31.5mm (1.24") diameter, rear axles and diff end of front axles.
27 tooth spl, 28.0mm (1.10") diameter, Land Rover 110 cv's – these details from memory need to be confirmed. The smaller spline size of the cv's reduce the strength of front axles below that of 24 spline rear axles – Ashcroft 24 spline, or Rovingtrack 30 spline cv's allow greater strength from the front axles.
Because of their small size the later fine spline cv's or older 10 spline axles are not considered here.

Dana Spicer,
30 tooth spl, 33.3mm (1.31") diameter
35 tooth spl, 38.1mm (1.50") diameter
37 tooth spl, 40.6mm (1.60") diameter
40 tooth spl, 43.2mm (1.70") diameter

Toyota,
27 tooth spl, 28.0mm (1.10") diameter, HiLux axles and cruiser cv's pre 80 series.
30 tooth spl, 33.3mm (1.31") diameter, Land Cruiser 80 series front and rear axles, 105 series front axles, 80/105 series cv's.
32 tooth spl, 34.8mm (1.37") diameter, Land Cruiser 1998 onward 105 series rear axles.

Nissan,
31 tooth spl, 32.0mm (1.26") diameter, Patrol GQ, GU, H233B high pinion front axles - I don't know the spline details of Nissan cv's.
33 tooth spl, 33.3mm (1.31") diameter, Patrol GQ, GU, H233B low pinion rear axles
34 tooth spl, 34.8mm (1.37") diameter, Patrol, H260 full-float rear axles.
37 tooth spl, 38.4mm (1.51") diameter, Patrol, H260 semi-float rear axles

Typically USA axles use imperial standard, side fit, involute splines with 24/48 DP (diametral pitch) and 30* or 45* PA (pressure angle), which makes it easy to simply compare them by spline count.

Note imperial involute splines use a standard stub tooth gear form with one value of DP (24 in this example) for pitch diameter and circular pitch (2 x tooth thickness at pitch circle) and a finer DP (48 in this example) for tooth addendum and dedendum (height above and depth below the pitch circle). With imperial standard involute splines, the finer DP for depth is always double the DP used for the circular pitch (thickness).

Land Rover and Salisbury 24 splines appear to be SI (International System) standard, side fit, involute spline of 1.25mm module. From memory the PA is 30*. The tooth depth is greater than that for 24/48 DP. BTW, the straight sided 10 tooth spline used elsewhere by Land Rover, appears to be SAE (Society of Automotive Engineers) standard.

I don't have any information on JIS (Japanese Industry Standard) splines.
Going from the given OD and spline count, Toyota splines could be imperial standard involute splines of 24/48 DP. The spline data for Nissan axles don't match imperial or SI standards – they may not be true involute profile (hard to tell with my old eyes).

The static torsional strength at the splined section of a shaft is a function of the spline root diameter cubed (not the outside diameter) and the shear strength of the material. Root diameter = spline OD – (tooth depth x 2) (fine splines are not as deep as coase splines). This strength is not used in shaft design, but regardless there is no gain by making the unsplined section of the shaft larger than the weakest section (e.g. root diameter of splines).

Shafts are designed for fatigue life/strength, which is less than the static strength and takes stress raising factors, material endurance strength, nature of loading (e.g. reversing or non-reversing), cumulative damage from number of cycles, reduction factors for size and material strength, etc. into account.

Rolled splines are stronger (fatigue) than cut splines because the rolling process produces residual compressive stress at the root of the spline. Rolling reduces cost when large production numbers justify the tooling cost, so I assume most OEM axles would have rolled splines and many aftermarket axles would have cut splines.

The strength of involute spline teeth will exceed the shaft torsional strength when the length of engagement exceeds approx 0.7 (from memory) x diameter. For wear life it may be necessary to increase the length of engagement, especially if not a tight fit.

Because the torsional strength increases by the cube of the diameter, it is folly to use high strength alloy steels for axles and shafts when a suitable diameter can be used with a good quality (fully killed) plain carbon or manganese (for toughness) steel – alloy steels would be used if weight has to be reduced or there is a practical restriction on size. Unlike the original manufacturer, we usually need to resort to alloy steels, rather than incresing diameter to achieve greater strength for use with higher loads or more severe impact/shock loads.

Even though Nissan 31 spline front axles may be a little smaller at the OD compared to Toyota 30 spline, their finer splines do not reduce the root diameter as much and as a result aren't far below. I can't remember what spline Nissan use at the cv, but Toyota use 27 spline at the cv for HiLux and Landcruisers up to 80 series. Longfield make 30 spline cv's for luxes and earlier cruisers, with axles to suit (from memory (Keith), Rovingtracks uses these 30 spline cv's for rovers).

There is little point making the front axle much stronger than the cv's – they will just increase the impact energy at the cv and diff. Toyota cv's from 80 and 105 series are 30 spline from memory and are larger and stronger overall than their opposition.

The Nissan 33 spline rear axle is the same OD as Toyota 30 spline rear axle, but larger at the root of the splines. The 105 series rear axle is a little larger.

Compared to Land Rover most 4x4's have stronger axles, or else are much lighter.

My hybrid front axle has a Nissan H233B, 4.11:1 ratio high pinion diff, ARB air locker with Toyota 80 series side gears, Toyota 80 series front axles and Longfield 80 series cv's. It was built to be used with my 105 series rear axle with air locker, 4.1:1 ratio ring and pinion. The rear housing is flipped so the pinion is close to centre on the left side, to better line up the rear driveshaft from my Atlas transfer case. Other than the air lockers (I regret not using Jack Mac lockers, but was in a hurry at the time). IMHO these to use the strongest combination of stock parts readily available here without going to the ovekill (and ground clearance loss) of either Nissan H260, or Sals with 35 spline axles.

Since relocating to QLD, I haven't tried to get them approved as they currently don't allow the rear track to be increased by as much as these would, and the fron't axle can't be changed at all. If this doesn't change with the anticipated adoption of the national code of practice, I have considered other options that are not as appealing.

Gun drilling doesn't increase the static or fatigue strength. It does reduce weight (at great cost) for little or negligible reduction in strength, because most of the torque is carried by material at greater radius from the axis – increases from zero at the axis (or inside diameter of a hollow. I can't see the sense in gun drilling axles smaller than Dana 40 spline, which for my purposes is cloud cuckoo land.

much thanks John, and I actually understood most of that

From what I can remeber, the explaination of gun drilling was that if you twist a shaft, the fibres/grains start to crush on/in the center , if you remove it it allows more twist, shock absorbtion. It is not stronger at UTS and im sure the weight loss is just a bi product....

I totally agree on when it would be appropriate, along with there must be some sort of clac/rule for how much to remove, given length,dia materail etc


On another board which you are familiar with, a certain Mech. Eng has been saying that Hytuf is not a great choice as there is NO one is Australia that can heat treat it properly....Do you have any idea on this?

Here is the info I posted on Outers years ago, from a page Mal gave me:

From Maxi drive.

ROVER FRONT AXLE CHANGE POINTS & MAXI DRIVE DIFF APPLICATION

RANGE ROVER DISCOVERY AND DEFENDER WITH ABS:
All vehicles with ABS brakes have the CV joint with the small weak 32 inner axle spline. The CV joint also has 72 serations on its outside dia. for the electronic sensor to "read" wheel speed from. The heavy duty AEU2522 CV joint can be fitted with a 72 tooth ring which is shrunk onto the body of the CV. However this increases the dia. of the CV which then means the inside of the hard chrome swivel ball has to be machined to provide clearance. The top swivel pin also has to be raised 2mm. to clear the 72 tooth ring. ABS sensor is adjusted to just touch as per normal set-up.


SPLINE SIZES & TOOTH COUNTS

10 SPLINE: Used for axle shaft to diff side gear in ROVER Type diffs from the first L/R in 1948 to app 1992. Also used in L/R series 1 & 11 vehicles at drive flange and early R/R & Disco CV joints.
Square form (40 o included angle) Major dia 28.2 (1.11") Root dia 25.3 (.997") Zp ( polar section) .212
App torque capability for axle of 1500 Mpa UTS Hytuf 5635 Nm (4160 ft lbs)

24 SPLINE: Commonly referred to as "Salisbury" spline as it first came into rover use in the Salisbury diff fitted to series 111 long wheel base. Also used at drive flange on series 111 onwards. From app 1994 the Rover Type diff also uses this spline in the side gear although this gear is about .004" tighter than the Salisbury diff gear. The side gear spline in all Maxi-Drive 24 spline diffs is also the same as the Salisbury. (Why Rover decided to depart from industry standard and make the Rover diff tighter is anyone's guess)
Involute form, flat root side fit, 20/40 DP, 30 o PA,
Major dia 31.4 (1.24") Root dia 29.2 (1.15") Zp (polar section) .294
App torque capability for axle of 1500 Mpa UTS Hytuf 7835 Nm (5780 ft lbs)

23 SPLINE: Only used as the inner axle to CV connection on the three decent CV joints, namely R606665 R/R ; AEU1828 stage one 111 and AEU2522 early county
Involute form, flat root, side fit 20/40 DP, 30 o PA,
Major dia. 30.1 (1.18") Root dia 27.9 (1.10") Zp (polar section) .281
App torque capacity of axle of 1500 Mpa UTS Hytuf 7450 Nm (5500 ft lbs)

32 SPLINE: This is the hopelessly small inner axle to CV connection used on all vehicles since app 1988. Not strong enough for the torque that can be applied with a across axle diff lock. For this reason all front Maxi-Drive diff locks use the more durably 23 spline size and if required the stronger 23 spline CV joints are used in place of the weak 32 spline CV joint.

Vee form 45 o PA, Major dia. 26.3 (1.035") Root dia. 24.1 (.950")
Zp (polar section) .192
App. torque capacity of axle of 1500 Mpa UTS Hytuf 5095 Nm (3760 ft lbs)


this was copied from a page given to me by mal, there may be some small mistakes.

I note you wrote 27 spline for the LR section, Im guessing this should have been 23.

Originally Posted by uninformed

much thanks John, and I actually understood most of that

From what I can remeber, the explaination of gun drilling was that if you twist a shaft, the fibres/grains start to crush on/in the center , if you remove it it allows more twist, shock absorbtion. It is not stronger at UTS and im sure the weight loss is just a bi product....

I totally agree on when it would be appropriate, along with there must be some sort of clac/rule for how much to remove, given length,dia materail etc


On another board which you are familiar with, a certain Mech. Eng has been saying that Hytuf is not a great choice as there is NO one is Australia that can heat treat it properly....Do you have any idea on this?

Once upon a time, when defects in steels were more prevalent, drilling along the centre would often remove the worst of the defects where cracks could start. Quality steel making with electrical furnaces and vacuum degassing the results are far better- it has for example made 4340 much better.

I'm no metalurgist but have trouble swallowing what was claimed about the benefits of gun drilling today.

I haven't had to get anything heat treated for some years now, so don't know who is still around. There were very good as well as average heat treaters and with some alloy steels only the best heat treaters would be trusted with them. There are steels more difficult than Hytuff that these people heat treated nearly every week.