Maxi drive axles strength

[uninformed]

i got this from Mal at Maxi drive the other day.

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.

cheers, Serg

[Slunnie]

Man, that is some reading. Makes you realise how weak they really are, and that its really only a lack of traction that stops the engine torque breaking things.

[ISUZUROVER]

Man, that is some reading. Makes you realise how weak they really are, and that its really only a lack of traction that stops the engine torque breaking things.

Yes but it assumes that the 32 spline inner axles are made from hytuf. If you actually look at the genuine axles, the 32 spline section and the necked down part of the shaft is blue while the rest is silver. They obviously subject the narrow section to a special heat treating process. Don't know what the material is though.

[HSV Rangie]

Might just put that into the FAQ/Tech section, lot of good info in this.
Michael

[Rangee]

is the heat treatment any better then the cryogenic freezing treatment they use on the drag engines....
i read an article in a engine building mag on it and wondered if it had any benifit for us ?
cheers
Rangee

[ISUZUROVER]

Cryogenic freezing is not a substitute for heat treating and it is still largely unknown as to why/if/how it works. All good steels (and many other alloys) must be heat treat to achieve proper hardness. Do a google or www.pirate4x4.com search on heat treating, nitriding, tufftriding, etc.

[bushy555]

>Spline counts

Can add 28 splines to the list. Mal used 28 spline axles on his early "version 1" maxi drive axles. Interestingly enough Mal used Ford 9" sun gears in the centres for those early maxi's.

Heh heh! ...and I managed to strip three out of six gears to pieces, back in February.