I have a 2005 Diesel Mazda Bounty UTE, which is also called a B2500.

I want to drain my gearbox oil. How tight should I tighten the fill and drain bolt?

Same question for my engine oil, how tight should the sump bolt be?

Should I expect to find this in my manual? I couldn't find it.

  • 1
    In the workshop manual - maybe not the handbook ...
    – Solar Mike
    May 14 '18 at 4:22
  • 2
    Also make sure you undo the fill bolt first. You don't want to undo the drain, empty the box then find the fill is jammed.
    – tobyd
    May 14 '18 at 15:20
  • I 2nd tobyd, also, the oil will come out steadily that way without sloshing, as it can suck in air from the filler hole.
    – Bart
    May 15 '18 at 9:27

The specified torque is in the workshop manual if you can get your hands on one. Maybe some searching on the web will give you an answer. But hardly anyone really cares about that, to be honest. Just grab on a new washer, clean the hole and the plug from any debris, and tighten it. It doesn't have to be really tight as with wheel nuts, just crank it about a quarter to half a turn further when you start to feel it's tightening, and you should be golden.


Interesting thoughts. I found a manual and it specifies the exact torque for the gearbox type. However you are right, that no mechanic will look up that kind of stuff for every car that comes in.

For your interest, the manual mentions 2 drain plugs which in itself is interesting. I only saw 1 when I looked, and yes on further inspection there are 2. Both needed to be drained.

The manual specifies 40 - 58 Nm for the drain plug on the bottom, and 21 - 31 Nm for the drain plug on the side. Plus 25 - 39 Nm for the fill plug.

I have done the drain and refill now, and I second the idea of making sure you can get the fill bolt off first. I spent about a week off and on trying to get the fill bolt off. It was so tight. Plus it was square, so I couldn't use a normal socket and breaker bar. I eventually used some heat from a small blow torch, and it came off after that.

The drain bolts came off easily. Based on how easy this was I changed the oil in my diff too using limited slip diff oil.


The engine drain plug, run it down by hand, then another 1/4-1/2 of a turn with the ratchet. Most engine drain plugs is between 20-30Nm.

Gear housing drain and fill plugs is often wide and more finethreaded, so they take more torque. But same here also, run them down, then snug them a bit more. No need to go crazy 😊

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