my vehicles must have been atypical
Somewhere down the line, some incompatible parts may have been installed. Those cars had MANY engine, transmission and rear axle choices and possibilities…See how many different driveshafts are listed for a 1970 Le Mans / GTO… I bet there is a half dozen possibilities…
well, I ve changed countless universals on 75 ford supercabs , they had a split shaft and a carrier bearing and three universals. I changed a couple on a jeep, but it has about a million different types of joints.
With the exhaust system in the way I can see how the OP may be having difficulty seeing what’s moving under there. So it’s hard to see what to do. I’ve removed the driveshaft on my Ford truck several times and never had this problem, but that drive shaft is a two-piece unit, splined in the middle, so it is easy to move it front/back to get the needed clearance after removing the bolts that hold the rear u-joint.
I think what I’d do in this case is see if I could put a separate jack under the differential and jack it up and down a little, as an experiment. Do this carefully, as it might imbalance the original lift. Best done without anybody being under the car, for safety reasons. Use a bright flashlight, dee if there’s a place where the driveshaft is moving fore or aft as the diff moves up and down, especially look at the transmission output area. That might provide a clue what needs to be done. In the meantime soak the various parts you know need to be removed with some PB Blaster or equivalent.
BTW: Suggestion to OP, make some witness marks on the various parts so when you get it off, you’ll know the orientation it is supposed to go back on again. Without the witness marks, it’s easy to put the stuff back together w/the wrong orientation and it will vibrate and cause you no end of grief.
Geez, 5 pages for a driveshaft R&R…I’ll go out on a limb and say there is no way that the driveshaft can’t move forward enough to drop the joint out of the saddle. That would be an interference fit on the slip yoke and the tailshaft housing would be cracked by now. It has to slip pretty significantly just to accommodate the rear end motion under normal use. More than enough to clear the Ujoint. You just have to pry both caps from the diff yoke and that is going to require a big pinch bar if they’re stuck. If you support the body with jackstands with the wheels off the ground, the rear end will tend to point downward in the front and give you a bit more room to slide out the shaft.
@wesw - you’re right for 2-piece driveshafts, but all the 1-piece drive shafts I’ve worked on look like the photo I posted. That applies to most rwd cars with live axles, I think.
yeah i m sure you re right. i think i helped (handed him parts) my son change one on his el camino once…
still seems like it should come off tho…
Yes I am back.
I have an update. In my last post remember I found out one of the inner c clips holding on the cap was wedged-bound-stuck and it wouldn’t move freely like the other one.
I pried it off but the driveshaft still would not move except it did slide down a little.
I finally got back to working on it today. I had to put the rear back down on the tires to even out the driveshaft. It then would up and down freely but would not move back and fourth much only 1/8" or so. I removed the caps and barley got it out of there by moving the car up and down a little and turning the driveshaft. If the caps are on, there is no way that shaft is going to get out of there.
I need to do some research on the transmission and differential to see if the are the correct ones for that car and ask around on the GTO forums on the correct driveshaft length.
My guess is about 3/4"-1" needs to come off but need to make sure everything else is correct first.
But the good news out of all this is I found out why my drive gear for the speedometer was moving on the shaft, it is missing the clip to hold it on the shaft.
The bad new is I hope it did not fall off and somehow got into the transmission and is ground up in there somewhere because I did not find it when I took off the tail shaft housing.
Glad to hear that you finally got that drive shaft off.
I wonder if you went to a GM dealer Parts dept…if they could give you a print out that showed what was installed in that car from the factory. This should list what tranny was installed and that may point to what driveshaft the unit calls for. Then looking up that shaft…should list it’s length.
I needed some info once and was surprised when they handed me a print out listing everything, right down to the glass type, and interior trim.
Maybe with this info you can find where the problem is. I’d hate for you to have the shaft shortened and two weeks later find the real problem. Then you’d have to order another new shaft, because this one is too short now.
thanks for updating us.
Yosemite
Nice dilemna to have though. The 70 GTO is the second prettiest body style after the 67. Just a personal preference.
Back in the day, a local guy bought a 70 model brand new and it was a beautiful car in bright red with a black vinyl roof. Unfortunately, he was vilified by many when it was discovered that he had ordered it with an automatic transmission, A/C, PS, and PB…
Not very popular options at the time but pretty desireable now.
For more than 20 years I depended on an old parts house owner who had a huge lathe type contraption to cut and align driveshats. He had accumulated hundreds of used yokes and shafts plus a good stock of new pieces and could modify old shafts and build new ones and install double cardon joints on single joint shafts. I tested driveshafts at 85 mph and never had to return one. There was no guarantee that a shaft would fit though. Only that it was exactly as ordered. I bought his double u-joint holding fixture for replacing u-joints when he retired and a local machine shop went into the driveshaft business but they hadn’t really caught on yet when I retired. Like so many jobs repairing driveshafts seemed to require a special tallent.
It may be easier to just do as RK describes, shorten the drive shaft an inch or two at a good drive shaft shop. If the tranny and axle work fine otherwise, it’ll simpler to shorten the shaft, IF you have a good shop.