Changing the rear axle gear

[-morten-]

Hi,

i am going to change the rear axle gearing on my 1940 series 50.

 

Do i need to take of the rear axle or is there another way?

 

Take care.

 

-morten-

[Gary Best]

I think you do. There are several guys on here that have made to change over. Hope they respond.

[kingrudy]

I would also like to do the same for my car 2Carb40 has done this and I hope he weighs in. 

 

Mike 

[1940Super]

Yes you do. You have to remove the torque tube to pull the propeller shaft off the pinion gear spline

[-morten-]

7 hours ago, 1940Super said:

Yes you do. You have to remove the torque tube to pull the propeller shaft off the pinion gear spline

 

thanks for the confirmation, was just hoping for quick fix.

 

20 hours job?

[Jim Nelson]

What do you want ?   Are you trying to instal a different ratio ?    Is your rear end one that has the split torque tube ?     If so, you can swap third members for a better crusung ratio.     That is the easiest.   Otherwise more involved.   Yes,  you will have to pull the axels to do any of the mods.    If not, I’ve been there and done different options.   E-mail me at  oldbuickjim@gmail.com.   Yup,  you will get dirty but that's part of owning one of the best cars built.    In my ‘38’ coupe,   I have installed over drive an now travel  easily  65 to 7- mph all day long.    My longest trip was 1800 + miles round trip.   Our cars can do it nicely.     

[Guest]

On 4/8/2019 at 12:19 AM, -morten- said:

Hi,

i am going to change the rear axle gearing on my 1940 series 50.

 

Do i need to take of the rear axle or is there another way?

 

Take care.

 

-morten-

Hey Mort

          Rolling the rear end out from under your 40 Super may seem like a drastic action, however, its much more efficient, (IMHO) overall. You will prolley end up splitting the driveshaft from the shaft on the front of the diff unless U were lucky enuff to find a whole matching 1940 3.6 ratio. Im thinkn slim ta none! Seperating involves remove the outer tube exposing a tapered pin thru the inner shaft(and shaft at front of diff) peened over when installed, hopefully salvagable enuff to be reinstalled upon ressembly, so carefull hammering, if that makes any sense? Then pulling the driveshaft off the splines of the diff shaft, varies in difficulty from slides right off, to heating with torch and watching yer 10 ton posilock puller and small chunk of driveshaft rocket accross shop after pounding on puller (UFTA), with heat on small driveshaft chunk until cherry and just about swung out from fatigue. As they say in the manual " reverse assy to reinstall", simple, Right? Good luck! Oh, forgot 2 mention reassembled shaft must be checked 4 runout per specs in manual! No "wobble" allowed!

Edited April 14, 2019 by Guest (see edit history)

[Jim Nelson]

Contact Dave Tacheny in MN.    He specializes in old Buick parts.   Big to little.   I’ve bought things from him and he’s great.   Waiting to get a complete ‘37’  40 series rear from him.   He is very knowledgable.   1-763-427-3460.      He is in Champlin MN.