My, my. It has been a long time. I've basically took the winter off from posting but not from working on the car. I put the car in a friends garage over the winter, put it up on stands and spent the winter addressing issues underneath. Oh, but let me back up first!
Before I took it over I tried to address the driveline vibration one more time. If you recall, I had replaced everything from the trans back in an effort to fix a nagging vibration. The only thing I hadn't replaced was the drive shaft which I had balanced. Out of answers I decided to replace the shaft. I couldn't afford a new one especially since I plan to eventually swap the trans which will require a new shaft anyhow so I searched for a used one. A friend finally found one which should be interesting to all 66-67 gm A-body owners running th-400s. The d-shaft he found came out of a 89 or 90 ford truck. 8 ft bed standard cab. Perfect length, larger diameter than stock, 1330 u-joints. All I had to do was browse NEAPCOs web sight for combination u-joints to fit my slip yoke and pinion yoke.
In front the Buick slip yoke has the S-44 u-joint with the internal clips so I used NEAPCO #21569BF which converts BOP s44 type to 1330. In the rear I have a 12 bolt with the puny 1310 joint so I used the 10134BF which converts 1330 to 1310. Of course I could've just ordered a new 1330 slip yoke and pinion yoke but I wasn't sure if this was going to fix my problem so this was the cheapest way to go for now.
So ok, I know the suspense is killing you. So I got the joints in and went to install the shaft but because the shaft is a larger diameter the Moroso u-joint girdles (straps) that I installed because of a broken locating tab on the pinion yoke wouldn't fit. So it was off to Pep Boys to buy new straps and bolts. I welded a tab on one of the straps to keep the joint cap in place and after much fussing and swearing I finally got the shaft bolted in place.
Now for the moment of truth. I hit the on ramp to the highway, ran it up to highway speed and...(que chorus of angels)...hallaluyah!(sp?) NO VIBRATION! It was that M.F.'n driveshaft all along. Son of a beetch!
So what did we learn kiddies? Well, apparently you can balance a bad drive shaft and still not fix it.
There's more but for now I'll leave you with some pics of the d-shaft fun. In the 1st, the F-250 shaft is on the top compared to the stock shaft and the 2nd is how I "fixed" the broken locating tab. I also included a link to another video I did from a trip to a local 1/8 mile track this past fall. Hope you enjoy.