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M75 gearbox oil change.

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M75 gearbox oil change.

Postby Iantochips » Tue Jun 10, 2025 7:03 pm

Hi, new to me '97 TFS54 with M75 gearbox.

Drained the murky gearbox oil- a lot came out, around 4+ litres. I read somewhere the 'box takes 3.5, but I've filled it with almost 5l and still not reached the level plug, the very obvious 24mm plug on the side.

The vehicle is dead level. What's going on? Also any advice on finding the drain/fill plugs on the transfer box gratefully received. I'm old, and this isn't my first rodeo with old vehicles, but I can't find and info or images on the net. Help!
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Re: M75 gearbox oil change.

Postby geeves » Wed Jun 11, 2025 11:09 am

Last time I couldnt fill a sump with oil it was because I forgot the drain plug. Gearbox capacities are aproximate. If you dont have any leaks keep filling
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: M75 gearbox oil change.

Postby geeves » Wed Jun 11, 2025 11:11 am

For the transfer there should be a drain plug right at the bottom and the fill about half way up. roughly in line with the drain
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: M75 gearbox oil change.

Postby Iantochips » Thu Jun 12, 2025 3:59 am

Thanks- I'll get under it tomorrow. The drain plug is in! I recollect making that mistake years ago. Now I'm old enough to make it again.

I'll keep filling it. I mean, it can only come out again, right?
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Re: M75 gearbox oil change.

Postby geeves » Thu Jun 12, 2025 10:43 am

On the earlier mua box there was a seal that occasionally fails between the gearbox and transfer case resulting in all the oil going into the transfer case.
Sanding your knuckles before starting work can help. That way you cant skin them
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geeves
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2013 Subaru XV

Re: M75 gearbox oil change.

Postby Iantochips » Thu Jun 12, 2025 8:47 pm

Ah, that would explain it, also explain the weep from the transfer 'box output shaft. Many thanks, the 'box already jumps out of 4wd without a hand on the lever.

I'm looking for a new(er) one. Not easy here in Portugal.
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