D2 - driveline mods ??

[brooksy]

Hi everybody,

I wanted to know peoples opinion on possible weak points in mechanicals, diffs, transfer case, drive shafts, etc.
I have a '03 D2 V8 SE Disco that I am in the process of doing a 2"-3" lift, F/R custom bar work & R/Sliders. I am wanting to fit 33x11.5x16 simex extreme trekkers or similar agressive tyres when offroad & I was wondering if I should do some mods to the driveline. I know that I am going to have to change diff centres to 3.9 or 4.1's to correct ratios but I wanted to see if anybody has heard of any breakages.

brooksy

[Slunnie]

The diffs break in the planetary gears and the rear half shafts will break if you give it some good stick. You may also do the rear tailshaft through the rotoflex coupling if you jolt it.

[brooksy]

Hi Slunnie,

I was going to post same question on d2au site (probably tomorrow) but if you could suggest some cost effective solutions to my weakest problem areas that would be great.
I remember watching the clip of you snapping something (drive shaft/ rear ??) in your diff, is that a common problem with larger aggresive tyres. I reckon they would cause more torque like stresses, would diff gears alone help with these stresses or is it more complex than that ?

thanks in advance mate,

brooksy

[Slunnie]

Gday Brooksy,

Cost effective? Oooh. For the diff, if you're fine with pulling axles and centres, you can probably rebuild them pretty cheaply yourself. Its just the planetary gears that break. The sun gears are fine, though I think the cross pin may be marginal also. If you break it, you can probably even rebuild it without removing the crownwheel. In terms of a permanent fix you're really looking at aftermarket diff centres like lockers, LSD's or 6 gear hemispheres. These are all a lot stronger than the standard Rover stuff.

The axles, Maxidrive or Jack McNamara replacement axles.

The bigger tyres do put more stress into the system, though it really just depends on how you drive it as to whether it breaks or not. If you drive it sensibly it will be fine. Just minimise wheel spin, dont let it spin grab, dont land it while full stick on the accelerator etc and it'll be ok. I go out on a trip at least every month with a group of fellas to drive difficult tracks and even with Simex tyres it was ok. What broke it was standing it on its rear wheels, flogging the ass out of it and running it into a shale step. It took a few goes, but it eventually broke the axle and the diff centre failed also. As I said anyway, you can still drive it reasonably hard, just have some mechanical empathy with it.

4.11's will make it worse as it transmits more torque to the axles by about 15%. Its jolt forces that usually tip them over the edge though.

[Redback]

Yep i can atest to the planetry gears breaking, funny thing was it was an accident, dropping the clutch with high revs when you have a 1.3t trailer and a cargo section full of gear ain't good :oops: apart from that whoopsie i've had no other dramas, and if you've seen the video i'm not soft on the Disco, trust me style_emoticons/<#EMO_DIR#>/laugh.gif

As Slunnie has said wheel spin is the killer of Disco diffs and axles, you gotta remember to back off when you have a wheel in the air so when it comes down nothing breaks, the beauty of the DII is the traction control, it means you don't have to attack most stuff as hard or with as much momentum as other 4Bs style_emoticons/<#EMO_DIR#>/biggrin.gif 8) or do what i'm doing, Maxi drive locker and axles :wink:

Baz.

[brooksy]

I have ARB airlocker in rear & was going to do the same in front (money permitting), so basically I should maybe look at some aftermarket axles as my first stengthening exercise as the diff ratio is a must if I am going to make both road & offroad sets of tyres 33".
What's the damage for a set of Maxi-drives or McNamara axles ??
Thanks fellas

brooksy

[Slunnie]

They're about $600-700 for the rears for HD axles. I really dont think there is a lot between them in terms of quality, though Mal from Maxi is awsome to deal with, whereas Jeff at JacMac's is quite an experience at times. They're different to the usual Rover axle as the D2 is a semi-floating axle setup.

For the diffs, make sure you get 4.11's, not 4.1's. The 4.11's are stronger. I've recent heard there is a mob in WA, cant recall the name though that have these manufactured and then move them OS. Ashcroft is another supplier, and from them will cost about $1500 landed and taxed.

[brooksy]

Thanks Slunnie,

Maxi-drive is just down the coast from me in Brissy so I might give them a call. Do you think I only need the rear axles or should I get both F/R axles & are the fronts about the same price.
If you find out the mob in WA let me know so I can compare prices with importing through Ashcroft. $1500 isn't cheap but if you reckon the 4.11's are better well I will get them instead of the 4.1's.

cheers
brooksy

[Redback]

Brooksy same in the front and maxi CVs as well as in the front when put the stronger axles the CVs become your next weakest link.

Baz.

[Slunnie]

Jordan Rover Tech in WA from what I understand do diff gears and I think Rovercraft also import them from KAM. Just check they're the strong 4.11's, not the 4.1's.

In terms of HD axles, personally I'd upgrade the axles that you lock. I left the fronts standard for a while and didn't end up using the locker much incase the front broke. When the front CV finally let off a good click one day while playing in a rut on a good side angle I bit the bullet and harrassed Maxi to sell me a HD front end. The front inners are about the same price as the rears, but the full front end including CV's is pretty expensive.

I'm not sure if you can upgrade to Maxi CV's if you run a standard or standard HD front inner axle. I think the newer CV is bigger with a ring around the bell and the inner I'm pretty sure has a different spline count to the original. You may need to check that with Maxi.

[brooksy]

I'll get some quotes this week.

Thanks a lot fellas for your quick response ! style_emoticons/<#EMO_DIR#>/biggrin.gif

brooksy

[Slunnie]

Brooksy, I'd be interested to hear what quotes and availability there is for the 4.11's.

[brooksy]

I'll post them up & let me know if you think they are fair or if you can get better !!

brooksy