How to change Jimmy diff oil

I hope this easy eight step quick guide is helpful to anyone that wants to service their diff oils. They can often have water in the oil especially if you take yours of road.

What you need:

Ratchet, socket set, square 10mm drain plug key, New filler plugs, oil drain tray, funnel, hand suction pump, oil catch container, thread lock and a heat gun if drain plugs are seized on.

Oil type and quantity:

G13BB Manual
Differential Oil (Front)API GL-5 1.35 litres 80W - 90
Differential Oil (Rear) API GL-5 1.5 litres 80W - 90

M13AA Manual
Differential Oil (Front) API GL-5 1.1 litres 80W - 90
Differential Oil (Rear) API GL-5 1.3 litres 80W - 90
(Courtesy of bigjimny.com)

1) Before parking the Jimmy on a level surface warm the car up by taking it for a drive so the oil flows better when you drain it.

2) Firstly you need to remove the filler plugs using a 10mm square drain plug key if you don't do this before the drain plug and they are seized on then you won't be able to refill it. If like mine the plugs had seized on and penetrating fluid is doing nothing at all, then a heat gun on the plug works perfectly. Don't be tempted to use 3/8" ratchet head it does fit in but not tightly and the already soft as cheese plugs may be churned up.

'If the filler plug is tight or rounded off try clamping a good pair of mole grips onto it then give them a good tap with a lump hammer.' (Wombat)

3) Place your oil drain pan/bowl beneath the drain plug and undo slowly, the tapered drain plugs do not tend to seize on like the filler plugs do so you should be alright. Catch all the oil avoiding not to spill any and check the oil to see if there's anything that shouldn't be in there.

4) Once the oil has drained wipe clean the hole along with the magnetic drain plug that attracts swarf. The tapered design seals well but a thread lock/sealant on the thread is recommended to avoid leaks. Replace plug.

5) Fill the diff back up with the correct type and amount of oil, you should see the oil start to trickle out the filler hole. A suction hand pump makes this easier or as Wombat suggests a funnel and a length of hose pipe.

6) Replace filler plug along with a new copper washer. Check all plugs are snug. A smidgen of waterproof grease around the plugs will help repel road salt and make it easier to remove next service.

7) Wipe away oil drips and check for leaks.

8) Pour the old oil that usually stinks into a suitable container and dispose of it responsibly at your local recycling centre.

Now enjoy your quiet, smooth and protected differentials....

Old plug



New plugs can be found here: www.bigjimny.com/store/differential-filler-plug.html

If the filler plug is tight or rounded off try clamping a good pair of mole grips onto it then give them a good tap with a lunp hammer, worked well for me

Sorry wombat it was you that suggested the funnel and hose pipe.

No problem, was a tip i found on here ages ago

wombat wrote: No problem, was a tip i found on here ages ago

I'm sure you mean a 3/8" ratchet A 3/4" is pretty huge

And BTW a 3/8" ratchet works fine on the diff plugs. So No need to worry if that's all you got.

Thanks, changed it.

TomDK wrote:

wombat wrote: No problem, was a tip i found on here ages ago

And BTW a 3/8" ratchet works fine on the diff plugs. So No need to worry if that's all you got.

Well the 3/8 square rounded my front diff plug and I had to use a chiesel to move it. Therefore I bought a 10mm square to prevent that happening again with a new plug.