Question 8v92 With Mh20 Transmissions

[questover]

When Going From Neutral To Forward It Takes 1 - 2 Sec. To Engage. Going From Neutral To Reverse It Takes 1/2 - 1 Sec. To Engage. Ouestion : Do I Have A Future Transmission Problem?

Also I've Tried To Get Tne Manual For Mh 20 Trans From The Local Detroit Dealer. No Luck! Any Sugistions Where I Can Find Manual For The Mh20 Trans?

Thanks Russ

[GJH]

Have you checked your hydraulics? Do the shifters feel "mushy"? What is the pressure at the tanks? Much more experienced hands than I will chime in with better specifics, I'm sure.

If you find a manual, let me know; I could use one too.

George

[SKYCHENEY]

I have a manual. It covers the M and MH gears. I copied it for Yachtsmanbill a couple of years ago. Actually, my copy came from another forum member. Maybe I should take orders. It's lengthy and it costs quite a bit to copy with the fold out diagrams. Let me know who wants them and I will go to Kinkos and get a price on doing the job. If they are doing a few copies, maybe we can get a discount.

[Pascal]

a delay engaging forward, but not reverse, is a sign of low oil level or pressure.

check your tranny level, warm, engine at idle, until you get a feel for where the cold / off level is on the dipstick (about 1.5" higher)

if the level is really fine, then you probably have a pressure problem.

[GJH]

Sky, I'd certainly be willing to provide funding; or a scanned and e-mailed copy would be good too.

George

[questover]

Sky, I would like one also. Russ You might start a new thread to see how many owners would be intrested.

[LIBERTY]

My understanding is that the hydraulic ram holding an Allison in forward is larger and more powerful than the one used for reverse due to the greater power applied in forward vs. reverse. This larger ram takes longer to "fill" at any given pressure, thus taking longer to engage in forward than reverse is normal.

[SKYCHENEY]

Sky, I would like one also. Russ You might start a new thread to see how many owners would be intrested.

Anyone who is interested in a copy of the manual, just send me a PM with your name and address. I'll find out what it costs to get it copied (and spiral bound, if you'd like). Then I'll send a PM back and you each can decide if you'd really like me to go ahead.

[Nonchalant1]

Do both of your gears operate the same? That's not too far out of line from normal. What's the pressure reading when it does this? If you increase RPMs to 800, what happens then? Don't worry, it's perfectly OK to engage and disengage an M20 at 900 RPMs, they're made to do that.

Doug Shuman

[SKYCHENEY]

Do both of your gears operate the same? That's not too far out of line from normal. What's the pressure reading when it does this? If you increase RPMs to 800, what happens then? Don't worry, it's perfectly OK to engage and disengage an M20 at 900 RPMs, they're made to do that.

Doug Shuman

In fact, the manual says that they can be engaged at WOT.

[questover]

I will be going to boat tomorrow - will check oils. SKY, I FOUND OUT THE COMPANY THAT BROUGHT ALLISION TRANS. "ACADIAN MARINE TRANS." PHONE 337 837 3636. I BROUGHT THE MANUAL TODAY PRICE $65.00. THANK'S RUSS.

[Nonchalant1]

In fact, the manual says that they can be engaged at WOT.

SKY,

I know. One of the boat tests done by the USCG in certifying a 53MY for commercial use for more than 6 paying passengers is to shift directly from fwd. to rev. while running at planing speed. Yeow!!

Doug

[questover]

FYI - Oils were fine. I called the factory. They said thats its normal for the delay going forward. Also the service manual says you whould have 130psi @1800 rpm. Thanks for input. Russ

[exsailor]

Russ/Sky
Is there more than one kind of Allison Manual (Owners vs Service) and which one did you buy for $65?

[questover]

Byron, The one I purchased is: SERVICE MANUAL M, MH Series Marine Transmissions SM19884EN. THE COMPANY IS: Acadian Marine Transmission - 217 Burgress Dr, Broussard LA. 70518 Phone:337 837 3636