HELP: Changing Oil in the Rear Diff. - advice needed

[mikeonb4c]

Thought I might, as a simple job, change the oil in the rear diff as don't know when it was last done (but probably 30k miles ago minimum). Can I ask:

1) How fussy are diffs about having their oil changed as recommended

2) Anyone done it? the workshop manual mentions new washers for level and drain plug once they've been undone. It also gives torqueing figures but do plugs like this really need torqueing - I'd have thought nice and tight was sufficient. Finally, the drain plug looks like it might be a VERY big nut (and I don't think I have any VERY big spanners). Is that right.

3) Is it best left to the Bongo garage to do when I take it in for injector seals, Auto transmission fluid change etc. as I imagine its actually a v cheap job in labour terms if you have a big spanner, spare washers and some savvy

...but I do like to do stuff myself when I can (put new pads on front brakes yesterday - amazed how simple it is once you've sussed what to do)

[splitpin]

Hi mikeonb4c, I think anything you can do yourself is worth it if it saves a bit of cash. I didn't put new washers on or use a torque wrench, just nip the plugs up so's they won't loosen themselves, no leaks at all.

[Simon Jones]

A few a few random notes from when I did front & rear:

In terms of what oil to use:

"Recommended lubricants are:
Standard vehicles-Genuine longlife hypoid gear oil SAE90 (GL–5),
Vehicles with LSD-Genuine slip less gear oil SAE90 (GL–6).”
But if you can only get hold of GL5 (75/90 Synthetic) gear oil, it won’t cause any damage to the LSD”

I changed both front & rear oil recently. I was unable to find any info about the quanties of oil required. For future ref, I found it as follows:

Front: just over 1 litre
Rear: just under 2 litres

It was cheaper to buy 5 litres from a motor factor, so I actually used the extra to fill & flush the rear diff. The front oil came out very clean, but the rear was black & thick.

I can't recall the sizes of the sockets required, but the drain & fill plugs are different sizes. I used imperial sizes rather than metric, but they were a perfect fit. I'm sure one was 15/16".

There were no copper washers that I can recall, but I can't be 100% certain.

I think the recommended service schedule is either 50,000Km or 100,000Km - so don't need doing very often.

You really need a set of ramps to get the clearance to get underneath.

Refilling is tricky if you dont buy the 1 litre bottles with the built-in filler pipe. I used one one those cheap syphon pumps which just the right size to fit the filler plug.

A good tip from Keefy - check you can undo the filler plug before undoing the drain plug.

[mikeonb4c]

Excellent guys - reassured by your words I reckon its 'game on'

I expect I'll opt to buy the more expensive 1 litre bottles for the (spout) reasons you say Simon, and because I only need to do the rear diff (1.4 litre according to the manual). I have ramps and I'm not afraid to use them - I wonder if the incline will make much difference to the amount of oil before it overtops the level plug

[bigdaddycain]

It was cheaper to buy 5 litres from a motor factor, so I actually used the extra to fill & flush the rear diff.

Nice one simon, i'll remember that when i do my diffs...

[bigdaddycain]

I have ramps and I'm not afraid to use them - I wonder if the incline will make much difference to the amount of oil before it overtops the level plug

I realize you are 2wd mike, so don't actually NEED to ramp the front, but it may be worth considering to ramp each corner to maintain a more level playing field?

If the ground is level (ish) it should be ok from a full level point of view...

If the washer is copper mike, play some heat over it with a blowtorch till it glows, to anneal it ,dip it in water to cool it, it'll be like new then, and make a good seal.

[mikeonb4c]

Thanks for the tips Ste.

On ramping, its the back end I'd be ramping just to make access easier (well - possible!). I don't imagine it will make a crucial difference to the level filling

Mind you, since I plan to take it in to Wheelquick for diesel injector seals and ATF change, should I just let them do it. When the car is on a raised platform, it is no labour cost at all to drain and refill the diff. really

[Simon Jones]

I dont think the extra height at the rear will make much odds to the oil level, but if you can get it done for next to nothing at Wheelquick, then go for the easy option