[Shop-talk] Coast in Neutral -the next great debate
John Miller
jem at milleredp.com
Mon Dec 12 10:32:09 MST 2022
> If you put a manually car or truck in neutral and release the clutch
> while going down long hills or coming to a stop at a intersection,
> are you doing any damage?
Ah, Mexican Overdrive as it used to be called.
You said 'release the clutch' so that's assuming it's a manual
transmission. You're pretty safe, most traditional manuals are
splash-lubricated and will do fine.
Maybe some DSG-type quasi-manuals maybe not so much.
Automatics it's potentially a problem, it depends on which end of the
transmission the hydraulic pump(s) that lubricate and cool things is/are
driven from.
The ZF 4HP18 was a notorious case, the hydraulics were driven off the
output side. Perhaps what you need for this, but they routinely blew up
a couple weeks after e.g. California smog tests where the engine was run
at 2500RPM in neutral for a few minutes.
John.
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