Transmission and Differential Oil Change

Technical Area Engine, Transmission, Exhaust etc
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  1. My model of MX-5 is: NC
  2. I’m based near: West Midlands
  3. I’m looking for technical help or recommendations on: Transmission and Differential oil change. I want to purchase new fill plugs for both the gearbox and differential cant find them anywhere on the internet. Any idea what size they are. I want to get spares in case the old ones are damaged when getting them out. Thanks
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Your not likely to damage the actual plug unless your really ham fisted.

Spray them with WD40 first.

Here are the washers

https://www.mx5parts.co.uk/differential-gearbox-drain-plug-washer-models-p-3140.html

They are 23 and 24mm plugs, so have those sockets available.

Lots of YouTube videos showing how to do it.

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The other usual tip is make sure you can get the filler plug out before you drain the oil.

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If you have a 6 speed you need to double check this bit! This is from memory and I admit to no specific knowledge but -
I think with the 6 speed, double check you’re removing the correct plugs, I seem to remember there’s another similar looking nut that mustn’t be removed as it holds gearbox internals. Hopefully a more knowledgeable person will add the true facts.
This previous topic may help

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I wrap the threads on the plug I remove with PTFE Tape then replace the plug, not had a leak yet. Just keep a roll of PTFE Tape handy, it’s cheap too from any plumbing store, Screwfix etc.

Roy

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Dead right. If you remove the wrong one from the side of the box, you’ve just removed reverse and fourth, from memory, and it takes a full gearbox disassembly to replace the bits which fell off inside… :flushed:

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Yeah that’s the off side (drivers) don’t go near that, you want the nearside (passenger) they are pretty obvious fill and drain plugs that side.

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