Under drive removal

[PatrickGrant]

I've removed clam shell holding brake shafts and foot linkage rods. The cross member to the rear of the under drive has another clam shell and plate. Question is what do I have to do to get the under drive out to change seals ? I have been Googling like mad, but can't seem to come up with an answer. Help !! Pat

[Bob C]

I think you have to pull the rear axle then remove the u-joint from the back of the dual high so you can pull it forward and out of the cross member.

Bob

[Joe K]

Originally Posted by Bob C

I think you have to pull the rear axle then remove the u-joint from the back of the dual high so you can pull it forward and out of the cross member.

Bob

Yes on that. The problem is the diamond shaped cross member "receiver" (which serves as foundation for the rear axle "push" and also to prevent the dual high unit from "rotating") is applied to the rear of the center back cross-member. AND the dual high is the first thing into the truck chassis - and it has to be the last thing out.

Original diamond receivers are riveted to the "rear" surface of the cross member. Sometimes in repair expediency, they were relocated using bolts on the front of the cross-member - which allow undoing the bolts and withdrawing the diamond receiver/dual high as a unit. (There is enough play in the spline/rear axle positioning on the spring clevis to allow this.)

But Ford changed the entire area in the 1930 Model Year and Borg-Warner transmissions/high speed rear ends - and again with retrofit replacement intermediate shafts. See discussion connected with this at https://www.fordbarn.com/forum/showthread.php?t=160035


The above pix shows the replacement intermediate shaft and the early version diamond receiver (and the splines it contains.)

Joe K

[PatrickGrant]

Thanks Bob and Joe. I'm glad I asked for advice before trying to remove it. More to think about now !!! Pat

[SeaSlugs]

yup - i had the same issue and was informed the U joint had to come off which means the rear axle has to be slid back enough to get to it...

it sucks just be very careful and try not to get under the truck when it doesnt have the rear axle under it for support...

[1crosscut]

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It's just nuts and bolts... lots of them!

[SeaSlugs]

Originally Posted by 1crosscut

It's just nuts and bolts... lots of them!

and pesky brake pins! and a bajillion cotter pins everywhere!

My advice on the dual high - DO NOT EVEN THINK ABOUT REMOVING THE RING HOLDING THE 3 PLANETARY SHAFTS/GEARS IN!!!!! I did and fubared the ring - it was heated and dropped on and as it cooled it drew tight at the factory (DGM&O). well you pry it off cold its ruined... Had to order a huge snap ring (like 3.5" diameter ID) and use a surface grinder to get it thin enough....So - leave the dang ring alone!