Mopar Muscle Association UK

Morning all,

Manual transmission advice needed, please!

I recently replenished the oil in my 4 speed with Castrol EP80 (the 'old' oil drained out pretty clear) but have noticed a huge increase in gear noise in the first three gears - the oil is topped up to the fill plug level.

Am I using the wrong grade of oil or is my gearbox simply started to wave the little white flag?

Other oil choices are:-
EP80w90
EP90
EP/ATF mix
ATF

TIA!

I have always been advised that AFT is the best thing to use in the 4-speeds otherwise they are heavy to use.
I have never owned one but have driven your car before Phil and changing to AFT made it shift much easier plus I wondered if the car picked up some torque too?

What does Pete use?

These old transmissions can get real noisy if you run them on thinner oil than EP90, and Dave is right, ATF is the hot tip for faster shifting. I put a 90% ATF 10% EP90 mix in Petes 4 speed for a compromise, and that seems to be fine. The other problem with running straight ATF is that unless all the seals are in good shape they tend to start leaking all over the place. Just out of interest, if you try running straight EP90 in a modern box to try and quieten it down you'll find you won't be able to change gear at all (been there done that) that's how I found out about blending it.

Blimey Blue, I thought you had used sawdust as usual....so that's what's leaked out over my upper torso twice............

BTW: As Blue says, it works great - it is the best shifting 4 speed I have driven.

Thanks for the tips, guys.
Blue - stoopid question but did you mix the oils in the bottles then add to the gearbox or did you just put the oils straight in and let the gears do the mixing?
Although ATF may make the shifts slicker, will it reduce the noise the first three gears have developed since the last gear oil change, especially as I'm going to solid mounts (poly for the gearbox)? Or will I just have to grin and bear it?!
Incidentally, what makes the properties of ATF & PS fluid so different from EP's?

With ATF in a manual box will it shift itself? :dink:

For a moment I was like but then I realised I had mis-read that Kev!

I just measure out the quantities and pour it in Phil, it will soon mix once you drive it. ATF will make the box noisier because it is so much thinner than EP, so it has the effect of opening up the clearances on the syncro sliders, that is the main reason it shifts faster, I suspect ATF is also "slipperier" as well making it a superior lubricant I believe.