Final drive drain plug - Land Rover Forums

Clearday714 · #1 11-09-2011, 07:29 AM

I am new to the Land Rover world. We have just acquired a 1998 Discovery and wanted to change the oil in the front final drives. The shop service manual shows a drain plug and a level plug. I can find neither on these units. How do you drain the oil and refill to the proper level?

Disco Mike · #2 11-09-2011, 08:38 AM

Have you actually crawled under and looked at your diffs? If so, and you missed the 2 plugs, I am not sure what to say.
The bottom one is the drain plug, the one, part way up the pumpkin is the fill plug.
Pull the drain plug, remove the magnetic mud from the plugs magnet, reinstall and fill thru the fill plug till the fluid comes out, 1.8 quarts.
Consider using a 85/140 gear oil for both the diffs and the t/case for a total of 7 quarts.

Savannah Buzz · #3 11-09-2011, 08:41 AM

Please take the time to download the RAVE tech manual set in my signature, has factory shop and owners manuals. Here is a single page that covers the diff drain, you want to use a 1/2 inch drive wrench to open the top fill hole first. If you can't open that, don't drain it. The auto parts store sell a handy pump for like $7 that fits a jug of fluid and makes it easy. Youl also want to do the transfer case, it has the same fill, but a smaller magnetic drain plug. If working under truck be sure wheels are chocked. Some use a pair of ramps, both on passenger side, to give more room on ones side.

Also check out our tech sticky area, has lots of write ups and pix of common repairs, and the high miles service list.

Savannah Buzz · #4 11-09-2011, 08:44 AM

Warm up on this project before you take on grease of the swivle (CV) joints.

Clearday714 · #5 11-09-2011, 09:49 AM

I have already changed the oil in the differentials. The manual shows the final drives separated from the differential by oil seals. It shows a diagram of the final drive itself with a fill plug and drain plug and a level plug separate from the differential. Are you saying that the final drives are lubricated by the differential?

Savannah Buzz · #6 11-09-2011, 10:55 AM

Great, then you are done. See attached of rear hub from RAVE. The diff oil goes all the way through the axle to the hub, where the is a seal to keep that from mixing with hub grease. Not sure about a drain on the axle, but there is a "banjo" bolt on the top, with a vent line that runs out of it. That is like a PCV vent. You might want to pull that bolt out and clean it, and poke a wire up in the vent line, mine was full of mud. This built up a little pressure, and the diff oil oozed past the rear axle seal and mixed with brake dust, making something that looks like rubber undercoating.

The front swivels have their own drain and fill points for a D1. See attached of front hub. The axle seal is the right most #8 on the drawing. There is the regular wheel bearing grease, and the swivel (CV joint) oil which has it's own drain and fill per wheel. Info on that on previous sheet sent to you.

Clearday714 · #7 11-09-2011, 11:58 AM

Thank you for your patience and advice. I have been using the Rave manual. When I used the term "final drive" I actually meant "swivel pin housing". If you look at the diagram on the right of

d1 diff drain.PDF
it shows a drain plug and a level plug on the housing. My swivel pin housing does not have these plugs (only the fill plug) which makes me wonder why. Were there some models made that don't have these? I have pictures but don't know how to attach them.

Savannah Buzz · #8 11-09-2011, 12:52 PM

Yes, you have "discovered" Rover engineering. Older models allowed easy drain, newer models just have the fill, proof once again that continuous leaking is designed in. Turn wheel hard to one side and you can stick a slim plastic hose from a pump down in there, but normally people just shoot in some more "one shot" "00" grade grease. Search with those terms and swivels or CV and you will find many posts, and I believe there is some coverage in the tech sticky area. Have seen photos of some adapter and plastic tube and large syringe.

Thanks for using the RAVE, many DIYers, being manly modern men, have no need of instruction manuals. This can be an expensive habit, both in time and money. Good thing for us that manuals are written on a basic level. Of course, the sizes of bolts and such are not given, as it is a known fact that dealer mechanics have reduced math skills, except when it comes to 1.347 minutes of overtime due.

Clearday714 · #9 11-09-2011, 04:47 PM

Ah I see said the blind man. Where do you all get your parts? i.e. bearings and seals One side appears to need a constant velocity shaft seal. In which case I'll also need to replace the inner hub seal.

antichrist · #10 11-09-2011, 04:59 PM

Only the earlier swivels had drains. When Rover started using grease the swivel housings they did away with the drains.
There's a list around here somewhere with quite a few parts vendors listed.

Atlantic British
DAP
Rovers North
Rovahfarm
I've been dealing with the first 3 for 30-35 years.

Bearings I usually get locally though, as they are generally cheaper.

"Final drive" in automotive parlance usually means the final unit with a gearing change, so that would be the diffs on a Land Rover.