How to flush out a 75W/90 manual gearbox

Notmyrealname

londonTiger wrote: »

This thread relates to this thread but I'm creating a new topic as it's a bit of seperate topic altogether,

basically trying to change the gearbox oil from a closed box manual gearbox.

A lot of people are simply draining the box and filling it with new oil. Now I'm sure just draining and filling it will get rid of most of the crap. But having observed kitchen sinks many times I know that the heavier deposits don't actually drain away completely, they're too heavy and just sit at the bottom and don't budge. I'm qworried that if I just drain and reful, the bigger bits of metal will remain inside.

No point. The drain plug has a magnet on the back to catch any metal shards. If you're getting metal deposits large enough not to budge you'll shortly need a new gearbox.

Notmyrealname

GolfBravo wrote: »

Yes. The transmission oil loses viscosity and breaks down over time, significantly decreasing the ability to prevent wear. Plus you have all those metal bits floating in your transmission doing further damage.

Definitely worth changing manual transmission oil somewhere between 75K and 100K miles.

Did my MK3 Mondeo about 110k. Made a world of difference. Wasn't cheap though.

forgotmyname

Water to flush out a gearbox... Seriously just leave the car as is and dont change it..

Your going to do more damage than you will leaving the old oil in there.

vikingaero

Take it to a transmission specialist who has the tools to pump/suck/hydraulically remove the old oil.