The gearbox on my 70 442 is leaking and I'm trying to remove it. Can anyone tell me what size nut connects the pitman arm to the gearbox? I thought it was 1 3/8" but that is too big and 1 1/4" is too small. Could it be metric? I'm trying to determine if the gearbox is original to the car and should be rebuilt by powersteering.com rather than replaced. The cast part number on the housing is 5691676 built the 290th day of the year. Does the 6 below the part number indicate this was cast in X6, 66, 76, etc? Since both the number 6 and number 9 are identical, I suppose the number could have been inverted in the mold. If that was the case the housing would have been cast on October 17, 1969 which seems quite early for a car that was assembled the third week of April, 1970. The gearbox assembly date code stamped on the gearbox cover is 091 0 (April 1, 1970) which would be appropriate for the build date of the car. I suppose the gearbox cover could have been moved from one gearbox to another........ Car has power steering. Looking forward to the feedback on this one.

 

1 5/16 is between 1 1/4 and 1 3/8

 

Thanks Joe. A math minor from Indiana University and that never occurred to me. The problem is I have a 1 1/4" and 1 3/8" box wrench but do not have any 1 5/16". The car is at my lake house which is in a different town than my primary residence. For the last 2 days I've run up there with tools and the gearbox is still on the car! I was just hoping someone would respond with the size they think it is. Tomorrow I buy a 1 5/16", 32MM and 33MM impact sockets. Hopefully one of them works. I'll also take my pickle fork and break the pitman arm from the center link if nothing else works.

 

Don't waste your money on metric sockets. It's 1 5/16.

 

Pitman arm pullers are cheap, effective and don't damage dust boots...

 

Another option is the Jeep Conversion. ( Done on both of my 70s .. that is if your not worried about numbers matching.

Here is the link on this site.

https://classicoldsmobile.com/forums...upgrade-36164/

 

Where is it leaking? 2 or 3 years ago my original box was leaking from the lower shaft seal, and I replaced that seal and it's been dry ever since. So it it's leaking from the lower seal you may not need to remove the box for a rebuild.