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Lower unit drivshaft assembly problem

G

gman41364

New member
I recently replaced the O-ring

I recently replaced the O-ring on the driveshaft carrier assembly in the lower unit. after putting it back together now I don't have reverse gear. from what i can tell I put it back together correctly. It's a '95 Merc 40 h.p. 4 cylinder motor. I have a manual for the 2 cyl. but the carrier assembly is different. Any clues as to what I've done wrong? thanks in advance.
 
"Have you checked the gear shi

"Have you checked the gear shift with the lower unit off the motor? You may have mismatched the splines on the shift shaft ("one spline off"). If so, you don't have to disassemble the gearcase.
Maybe the gear was in forward and the control cable in neutral, when you put it together.
Robert"
 
"Marc,

I agree with the pre

"Marc,

I agree with the previous post, but would add one thing. If you took the lower unit off when you did this job, you might have put it back together with the lower shift shaft completely out of whack.

On many Mercs the cam that moves the shaft that the clutch dog is attatched to, can be rotated a full 360 degrees. You can easily make a mistake here, and be off by qutie a bit, in which case you could get forward and neutral, but not reverse.

I always put these together in neutral, because you can feel the cam lock in place. You can be in forward, and the shift shaft could be off by 45 degrees.

Tony"
 
"thanks for the help. I didn&#

"thanks for the help. I didn't take the lower unit off just the prop, a nut that has outside threads on it that screws on the outer circumference of the housing and a washer with teeth on it that were bent up to prevent the nut from spinning after tightening. after I had pulled the carrier housing out I did pull out the shaft from the lower unit (that the prop is bolted on to inspect the area) this was probably my mistake as I may have rotated it and didn't put it back in the same spot. Will I just have to put it in and try it a few different times til I get it right or is there a way I can put it in neutral or a gear to make sure it is in its correct position? thanks again, mark"
 
"If you are not getting revers

"If you are not getting reverse, you must have overlooked something. There is a rod that sits in the front of the prop shaft. The cam pushes against it to move the dog into neutral and reverse.If you took out that rod you may have lost the ball bearings that it pushes against.

Tony"
 
i think I have it fixed. I did

i think I have it fixed. I didn't have the carrier assembly tightened down enough it seems. I now have reverse and forward on the wet test in the driveway. hopefully I can get out on Saginaw Bay this weekend to try it out then check the gear oil for water after the trip. thanks for all the help.
 
"Mark,

The ring nut must be

"Mark,

The ring nut must be tightened to at least 110 ft./lbs. or else the o-ring will leak.

Tony"
 
"thanks for the info Tony. the

"thanks for the info Tony. there must be a special tool for that nut then I'll have to look for at the dealer to make sure I've got it right. No leaks into the gear oil after two trips fishing, so far it looks good."
 
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