Driveshaft Pinion Nut removal help

Jeffrey GH

Cadet
Joined
May 19, 2008
Messages
6
Can anyone tell me how to remove the nut on the bottom of the drive shaft. Maybe it is just being difficult, but then I got to thinking maybe it is a left handed nut instead of regular.

90hp 1983 Chrysler, 908V3B. I have had it for 20 years and never had a problem. Couple weeks ago the clutch starting slipping and I now know about the challenges of finding someone to work on it and finding parts.

Thanks
Jeff
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Driveshaft Pinion Nut removal help

It's not too difficult if you know the trick. And the procedure is in the manual that you should buy if you intend to continue to work on the engine.

The nut is a 3/4 right hand thread. However, it is torqued onto the shaft at 85 foot pounds so it is tight. You must use a 3/4 six point socket and a 1/2 inch breaker bar. Wedge a block of hard wood behind the socket and breaker bar to keep it from slipping off the nut. Pad the breaker bar handle well where it contacts the aluminum case. There is a special tool to adapt to the splines at the top of the shaft but I have found that if you are careful and pad them well, a Vise Grips will work. Clamp them firmly onto the splines and whack them with a rubber mallet. If you have an old crankshaft lying around, use it instead and you will definitely not mess the splines. After you remove the nut, hold the shaft vertical and whack the case with a rubber mallet to pop off the pinion--it will not just fall off.

Factory recommends a new pinion nut torqued to 85 ft. lbs. but I have not had problems re-using the old one.

Now, you say the clutch is slipping. The dog clutch can not slip--it can disengage and re engage with a bang.
If this is your problem, the dogs on the clutch and gears are worn and rounded. They CAN be re-ground square with a dremel and a carbide bit or better yet a stone. Drill press is a little more accurate.

Since the forward dogs get 90% of the wear, sometimes if the forward gear is not worn too badly, you can just reverse the clutch and presto-zingo--- you are on your way for a couple of seasons more. And this is without removing the pinion and forward gear.

If you do elect to remove the pinion, be certain to retain all the shims from the top bearing--they locate the pinion in relation to the other two gears. Lose one and your gears will self-destruct in short order.

When you do re-attach the pinion, be certain to torque the nut to 85 ft lbs. This is important because aside from having the nut tight enough to not work loose, it ALSO locates the pinion gear on the taper and in relation to the other two gears.
 

Jeffrey GH

Cadet
Joined
May 19, 2008
Messages
6
Re: Driveshaft Pinion Nut removal help

Thanks Frank, That is exactly what I needed.

Yes, the clutch is disengaging with a bang. The dogs on the clutch are a little rounded on the forward side. The reverse side looks very slightly rounded, but it appears to be built that way.

Are the dogs suppose to be a sharp edge?

I like the idea of not removing the pinion, maybe I will give it a try.

Thanks again!!
Jeff
 

Jeffrey GH

Cadet
Joined
May 19, 2008
Messages
6
Re: Driveshaft Pinion Nut removal help

Well I finaly had a few minutes to work on the nut and got it off no problem. Now I can not get the pinion gear to come off. I held the shaft and then hit the case with a rubber mallet, several times, harder and harder.
Any suggestions?
 

fishinrado

Petty Officer 2nd Class
Joined
Nov 8, 2006
Messages
137
Re: Driveshaft Pinion Nut removal help

hi jerry, just reading your post as i'm in the midle of a rebuild myself and i can not get the pinion gear to stop spinning freely on the driveshaft. did you get yours off? i'm trying to figure out if i needed to remove the driveshaft or at least pull it up so the gear can come out. i tried the rubber mallet idea but mine did not come off either! thanks........
 

Chachi420

Seaman Apprentice
Joined
Apr 25, 2006
Messages
38
Re: Driveshaft Pinion Nut removal help

Well I finaly had a few minutes to work on the nut and got it off no problem. Now I can not get the pinion gear to come off. I held the shaft and then hit the case with a rubber mallet, several times, harder and harder.
Any suggestions?

Did you figure it out?

I am having the same problem--that is to say that the pinion gear is not coming off the drive shaft after the pinion nut has been removed. The service manual simply says "Remove the pinion gear" after the nut has been removed, and it does not mention any other tips.

I'd love to hear if there are any tricks to making it work! :)

Thanks!
 

fishinrado

Petty Officer 2nd Class
Joined
Nov 8, 2006
Messages
137
Re: Driveshaft Pinion Nut removal help

hey i did get mine off and all i had to do was pull up on the driveshaft and it came right off. this was of course after i removed the water pump and housing. you'll be able to see the bearing that the drive shaft go's through once the housing has been removed. my whole problem was the splines on the bottom of the drive shaft just wore off and the pinion gear was just free spinning around and not moving the forward and reverse gears. see my post under 'pinion gear ?' and pics"........
 

abcd462

Recruit
Joined
Jul 14, 2008
Messages
4
30

30

take ib profen 2oomg - 400mg every 4-6 hours and eat when you take it.. it will only cause damage if you abuse it plus if you eat the risk is greatly dcreased. i love dental health sudaphed for runny nose w ib when w a cold...thats the olny way to over come my colds and no stomach lining damage
 

Jeffrey GH

Cadet
Joined
May 19, 2008
Messages
6
Re: Driveshaft Pinion Nut removal help

I finally had another day to work on the unit. Can't believe it has been over 6 weeks since I last logged in.

Here are the results:

I did get the pinion gear off by placing the narrow part of the shaft in a vice and then putting pressure on the housing by placing a screw jack between the housing and the vice table. Once I had slight pressure on the housing on the back side of the shaft, I hit it with a rubber mallet and the front side and it popped off. The gear and shaft were fine, it was just being very stubborn.

My original problem was that the dogs on the clutch and gears were getting rounded and it was jumping out and back in gear with a bang.

I took Frank's advice (see below) and used a dremmel to square up the dogs on the gears and the clutch. I bought a seal kit (used about half of the items) and it went back together fairly easy.

I had the boat out yesterday and it ran great with no clutch banging. So for $50 and about 20 man-hours (stretched over a 3 month period), I am up and running.

Thanks again Frank, I could not have done it with out you!
 
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