Hi guys, I took my 48’ gmc to get a new clutch and it seems this leak started shortly after. The weird part is it seems to have gotten progressively worse. It started as a just a small drip a day to a 4 inch spot a day in about the last 2 weeks. Anyway I was wondering if there was a way for a novice mechanic as myself to fix it without taking back to the shop. Take a look at the photo and let me know what you guys think. Thanks
Back the nut all the way off, and see if the seal between the nut and the pivot ball is damaged or missing. Those are still available, and I believe some of them have a diagonal cut that allows the gasket to be installed without dismantling the entire torque tube/universal joint assembly. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Jim I have reviewed enough of your posts to realize that you have a 48 GMC 1/2-ton truck. It should have a full length torque-tube that goes from the ball and socket joint at the rear of the transmission to the rear axle - in one piece. So, I don't understand the picture you posted of the "collar". Unless it is a long wheelbase 1/2-ton. I don't have any experience with them. It looks like a slip joint in a 2-piece driveshaft. What is mounted at that crossmember?
Last edited by Frank50; 09/20/20193:34 PM. Reason: edit text
I'm more confused. Jim, the picture you posted is similar but clearly different than the pictures Tim posted. It looks like the second (rear) ball and socket, and its mounting bracket, are missing. If that's the case, I don't see how it works at all. That is, if it still has torque-tube drive. I agree with Ed and Jerry, there has to be a seal of some kind in that threaded collar. Some more pictures will be helpful.
Start off by checking if the sm420 is over filled with gear oil. I have seen leaks out of the front like that since the rear bearing retainer is open to the collar with no seal on these models If gear oil comes out the fill plug than it has two much oil in it.If that is not the case, then remove the collar and check to see if you have the two little metal washers that sandwich the torque tube seal. If one or both were omitted on reassembly then there is your smoking gun.
Steve
Last edited by sstock; 09/21/20195:01 PM.
1953 Chevrolet 3100 261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done In the DITY Gallery Video of the 261 running
1964 GMC 1000 305 Big Block V6, sm420, the next cab off restoration
I'm more confused. Jim, the picture you posted is similar but clearly different than the pictures Tim posted. It looks like the second (rear) ball and socket, and its mounting bracket, are missing. If that's the case, I don't see how it works at all. That is, if it still has torque-tube drive. I agree with Ed and Jerry, there has to be a seal of some kind in that threaded collar. Some more pictures will be helpful.
FRank the difference is because up to 1954, one is the extended bed length 1/2 ton without carrier bearing and the other is a 3/4 ton truck with carrier bearing, in both instances they have a not sealed rear bearing housing on the sm420 that needs the torque tube bell/collar type assembly
Last edited by sstock; 09/21/20191:33 PM.
1953 Chevrolet 3100 261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done In the DITY Gallery Video of the 261 running
1964 GMC 1000 305 Big Block V6, sm420, the next cab off restoration
