Transmission seal replacement

[Jflr]

Lehman 135 , Borg Warner velvet drive transmission. Prop turns clockwise. I have a small transmission leak and want to change the seal.
My problem is I can’t tell if the 1 11/16” nut holding the flange to the transmission shaft is a reverse thread. It won’t move in either direction easily and I don’t want to use more force until I’m sure. There aren’t any threads protruding from the nut to tell. Can anyone tell me whether it is a left or right hand thread? Can I use heat on it to help loosen if necessary?

 

[Comodave]

I would use an impact first. I have a 1/2” impact that would probably break it loose.

 

[jleonard]

I don’t remember what the torque is on that nut but its a lot. I used a long piece of angle iron and two bolts to hold the flange ( braced against the floor) and a long breaker bar with a pipe attached to loosen ( and tighten) the nut. I believe it was a standard thread.

 

[SteveK]

Had a look at my service manual and only one nut is listed in parts which suggests CW thread

 

[Jflr]

Thank you for the quick replies. The specified torque is a lot, 200 to 250. I have bolted some iron to the flange to steady it and I have a long breaker bar and pipe. I’ll give it another try tomorrow and assume it’s a standard thread. If I can’t move it, will applying heat help (or hurt)?

 

[Jflr]

I would use an impact first. I have a 1/2” impact that would probably break it loose.

Good idea, but I don’t think I have the clearance because of the prop shaft.

 

[Mac2]

Not familiar with that transmission, but it seems like there should be a bearing on that spinning flange. I would be worried about melting the grease out when applying heat. A parts break down should show any bearing in that area. Otherwise, heat would definitely help. Might be a matter of ordering a bearing to have on hand just in case.

 

[jleonard]

One thing i just remembered is to put sealant on the splines when you re assemble the flange. This will prevent oil from leaking thru the splines. Got that tip from a then old timer at my local velvet drive distributor.

 

[Jflr]

One thing i just remembered is to put sealant on the splines when you re assemble the flange. This will prevent oil from leaking thru the splines. Got that tip from a then old timer at my local velvet drive distributor.

Thanks, I heard that too and have some on hand.

 

[O C Diver]

Take a piece of cardboard and cut a peace that will fit inside the flange. Then make progressively larger cuts until it goes over the nut, and then measure it. Dont know if vernier calipers would reach inside the flange, but that would be my first choice.

Ted

 

[Jflr]

So I tried heat, penetrating fluid and brute strength with no luck. I was able to move the prop shaft back enough and borrowed a 1/2 drive impact wrench. Worked like a charm! Thanks for all the advice.

 

[Mac2]

Good to know. Thanks!