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A d v a n c e d   A u t o   M a i n t e n a n c e




 

Changing the manual transmission fluid…


Because the manual transmission fluid level should be checked once every 12 months or 20,000 kilometres (12,000 miles), whichever comes first, it’s a good idea to replace the fluid altogether at that time since it’s almost as time-consuming to check the transmission fluid level (which requires jacking the entire vehicle up so that it’s elevated and level) as it is to replace the fluid altogether.


The manual transmission is a closed system, generally without filtration…

The manual transmission is a closed system, generally without any kind of filtration of the fluid inside it, although many manual transmissions have a magnet embedded in the inside of the drain plug to attract and capture metallic particles in the fluid.  So changing the fluid once every 12 months or 20,000 kilometres (12,000 miles), whichever comes first, is a small price to pay to purge the transmission of all the tiny metal particles deposited into the fluid over the course of the operation of the transmission over 12 months (involving innumerable gear changes) as metal components inside it wear against each other.

If these tiny metal particles are allowed to accumulate in the fluid, they’ll exacerbate wear inside the transmission and reduce the working life of the transmission.  Considering how much work the manual transmission does over the course of twelve months (irrespective of distance travelled), it makes sense to change the fluid every twelve months.


Clean the drain plug thoroughly when replacing the transmission fluid…

If your vehicle’s manual transmission has a drain plug with a magnet embedded in the inside of it to attract and capture metallic particles in the fluid, be sure to inspect the size of the particles captured and clean them thoroughly off of the magnet when you replace the fluid.  If you find that there are largish metallic particles on the magnet, these could well be the result of rough gear changes which cause parts of the teeth of the gears to be chipped off.  Since the manual transmission is precision-engineered and expensive to repair, it pays dividends to treat it carefully when changing gears in order to minimise wear and maximise its service life.


Drain the fluid when it’s hot in order to remove the most contaminants...

In order to remove the most contaminants (such as tiny metal particles) from the manual transmission when draining the fluid, it’s important to drive the vehicle beforehand for, say, fifteen minutes after the highest engine operating temperature has been reached.  A greater proportion of the contaminants will be removed when the vehicle has just been driven and the fluid being drained from the manual transmission is hot due to the heat generated from its operation.


Use a high-quality manual transmission fluid additive…

Use a high-quality manual transmission treatment with each fluid change such as Nulon G70 Manual Gearbox & Diff Treatment.  This kind of additive contains PTFE particles (i.e. polytetrafluoroethylene) which reduce friction and wear inside the transmission, improve the operation of the transmission, promote smoother gear changes and will help to increase the life of the transmission.





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Copyright 2016 Andrew Mackinnon.  All rights reserved.