[Rovernet] Hello? Is this thing on - P4/P5 diff backlash

[Juliet Keiler]

Fletcher,Roland,Kent

Many thanks for your reply and the information contained within. I think by removing the half shafts the diff unit will pull out from the axle casing with all the gear wheels bearings etc attached.

There is some noise from the axle but it's not excessive and fortunately most of the internal components including planets gears, diff and pinion are available as NOS GENUINE parts from Land Rover Series specialists though the ratio on Land Rovers was 4:5 / 1 and not sure I want to go that low! Armed with your information I can remove the diff unit and check for play in the thrust washers whilst at the same time I can check the condition of the gear teeth.

Roland, your offer is most generous and I'm pretty certain it would fit as the diff pinion carrier for MK III P5's is the same part number as my 90 although of course the internals are different ratios. 4:3 / 1 on overdrive equipped cars and 3:9 / 1 on non-overdrive cars ( which is what I have) so 3:54 / 1 may help with the heavy fuel consumption! 

My concern would be the shipping costs, let's face it a diff is not light and even by sea to the UK may not be cheap and I may be able to achieve the desired results for the same cost of the shipping though I must confess the idea of the higher ratio does appeal.

I appreciate all your comments and it's nice to see Rovernet is still doing its job dissemination of information and assistance, I hope Eric is looking down with a sense of pride.

Regards

Alan (partviking)

Sent from my iPad

> On 29 Sep 2013, at 17:43, Fletcher Millmore <gofanu at cust.usachoice.net> wrote:
> 
> Alan-
> "...significant rear axle backlash, what is the likely cause?"
> 
> If the axle is not noisy, then the cause is likely NOT anything to do with the crown/pinion or their bearings.
> There will rarely be any actual wear on the main gear teeth, if the thing was not run without oil. In that case, the gears are usually beyond hope, and noisy. .
> 
> The usual reason for excessive slop in the works is wear to the thrust washers on the actual differential side and planetary gears - the small gears in the middle of the unit.
> There are flat bronze washers behind the gears the half shafts fit into, and spherical ones for the planetary gears on the pin in the center.
> 
> It is possible on most diffs to replace these without interfering with the main critical settings, and sometimes without even removing the diff from the axle. I recall doing a number of LR ones, but not how I did them. You need to figure out how to get the pin out that the planetaries are on; it it usually retained by a taper pin driven in through one end.
> 
> I reckon it would be easiest if the washers, and possibly the cross pin, are LR parts - as they may be, but: There is a remarkable amount of cross fertilization between axle manufacturers and designs worldwide (because it it such a specialty and involves lots of patents and licenses), so it can be worth trying to match up bits at a knowledgeable diff shop.
> 
> FRM
> 
>> On 9/29/2013 3:49 AM, Juliet Keiler wrote:
>> Hi Roland,
>> 
>> Like you I have been surprised at the lack of emails I've been receiving over the last few months and now realise that I was also on the yahoo group rather than the Rovernet one.
>> 
>> As a result I have had the odd mail now and then but not much more than that.
>> 
>> If nothing else your email has ensured I sign up to Rovernet.org and hopefully will receive ALL the emails sent.
>> 
>> Now to the question, my P4 (90,000 miles covered) has significant rear axle backlash, what is the likely cause? Is it wear between the crown wheel/pinion teeth or just their respective positions to each other. If I were to strip and rebuild (fortunately most of the items are also Series Land Rover so available at a reasonable price) what should I look at replacing?
>> 
>> Regards to all
>> 
>> Alan Francis (partviking)
>> 
>> Sent from my iPad
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