Allison m20 service manual or advice

[Goldy46c]

Hi,

im after advice for slow shifting m20 transmission

where is the strainer located?

oil pump pressure test point location?

oil pressure specification?

oil pump adjustment location?

or does anyone have a pdf service manual they could email me.

cheers.

 

[SKYCHENEY]

Call Acadian Marine. They will help you.

 

[Pascal]

99% of the time with Allisons slow shifting in forward is caused by low oil level. Level must be checked with engine idling in neutral.

 

[Goldy46c]

99% of the time with Allisons slow shifting in forward is caused by low oil level. Level must be checked with engine idling in neutral.

my thought also but have always ensured oil is correct height. how fast should they shift mine always take about 3 seconds for forward or reverse is this normal?

the problem trans is now at about 5 seconds.

 

[Goldy46c]

Call Acadian Marine. They will help you.

im based in Australia, once i get a hold of a service manual i should be right.

cheers mate

 

[SEVEN]

Sounds right.

 

[Pascal]

my thought also but have always ensured oil is correct height. how fast should they shift mine always take about 3 seconds for forward or reverse is this normal?

the problem trans is now at about 5 seconds.

They should shift within half a second or so, really no noticeable delay. 3 seconds is way too slow. Low oil causes the delay only shifting fwd not in reverse. How is the pressure ? Since I repowered it s been a while since I ve had to deal with them but I remember the gasket under the screen housing being sensitive to air leaks since it s on the suction side. That would cause delays or no shifting at all

 

[cww]

My allisons shift in 1-2 seconds. It doesn't take very long, but it's not instant like the twin discs in my last boat. Both sides act the same, and my boat acts the same as my dad's Hatt, so I'm pretty sure that's normal performance. Taking 5 seconds to shift sounds like you'd have issues docking, that would be a lot of preplanning of moves if you have to wait that long each time you need thrust. Old steamships with an actual guy down in the engine room turning a wheel were probably faster than that.

 

[Goldy46c]

My allisons shift in 1-2 seconds. It doesn't take very long, but it's not instant like the twin discs in my last boat. Both sides act the same, and my boat acts the same as my dad's Hatt, so I'm pretty sure that's normal performance. Taking 5 seconds to shift sounds like you'd have issues docking, that would be a lot of preplanning of moves if you have to wait that long each time you need thrust. Old steamships with an actual guy down in the engine room turning a wheel were probably faster than that.

It's a nightmare docking especially been my first boat but so far so good no accidents, suspect I've got a low pressure issue I've ordered a manual so I'll dig into that and get some guages on the trans to check pressure.

 

[Captain Ralph]

What RPM are you idling at?

 

[Goldy46c]

What RPM are you idling at?

idlind at approx 580