Click on image for the lowdown. 
====
| | | Forums66 Topics128,101 Posts1,056,179 Members48,436 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: Jul 2011 Posts: 257 Shop Shark | | Shop Shark Joined: Jul 2011 Posts: 257 | My truck is a 1959 1/2 ton, SM420 and a 3.90 Diff. I aquired a driveshaft with the engine I bought and it turns out that it is too short. So I took a bunch of measurements and brought the driveshaft down to out local shop. When I got there they asked where the slip yoke was. I preceeded to tell them that I did not have one and there was no contingency for a slip yoke on my SM420; mine has a bolted on carrier for the U-Joint. They told me that the job was going to be more expensive because they had to weld some sort of slip style shaft in there to compinsate for the up and down movement of the truck; made sense to me. After they took my info, they said they would call me the next day with a quote. Well they did and it was in the tune of $420.00  I almost dropped the phone. I can't be the only person trying to install a driveshaft to an SM420. Is this a normal price?? I payed less for my engine and trans than this. | | | | | Joined: Jul 2005 Posts: 946 'Bolter | | 'Bolter Joined: Jul 2005 Posts: 946 | A custom made drive shaft for $420 doesn't sound outrageous to me, maybe a little high, but not outrageous.
Why not try to find a used one? I'm sure you can find one fairly easily. Definitely needs a slip yolk.
| | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | explain a bit better what you have - is this "bolted on carrier for the U-Joint" the bell fitting for a torque tube setup? do you have a long bed with a split shaft and a steady bearing? wrong trans from earlier or bigger truck? a 59 1/2T trans should have a slip yoke
Bill | | | | | Joined: May 2005 Posts: 8,878 . | | . Joined: May 2005 Posts: 8,878 | That's not far off if the shop is supplying all new parts, assembly, and balancing. | | | | | Joined: Jul 2011 Posts: 257 Shop Shark | | Shop Shark Joined: Jul 2011 Posts: 257 | My truck is a short bed. The tranny has a bolted on u-joint carrier and as stated earlier will need a slip spline added to the driveshaft. I have been calling around town and I'm getting better quotes than the one stated earlier, it pays to shop around. Thanks for the reply's | | | | | Joined: Feb 2006 Posts: 1,867 Shop Shark | | Shop Shark Joined: Feb 2006 Posts: 1,867 | Sounds outrageous to me if they are modifying your original.
I would probably expect about that or a little more if they were building a complete driveshaft for you.
Just my opinion...
Jeff | | | | | Joined: Jul 2011 Posts: 257 Shop Shark | | Shop Shark Joined: Jul 2011 Posts: 257 | So I go to that driveshaft shop this afternoon to pick up the driveshaft that I dropped off the other day for an estimate. I'm talking to the lady at the counter and I ask her if they would match the lower prices of other shops in town, she said no that's not in their policy to do such things. She did say however, that they could build me a driveshaft with some good used parts for 1/3 less the price of the driveshaft quoted earlier. She went on to say that the guy giving the quote should have mentioned that when I told him that that was too expensive for me instead of loosing my business. In the end, I'm getting the proper type of driveshaft, that's going to look and perform just like a new one for 1/3rd the price. Happy camper | | | | | Joined: Jul 2011 Posts: 257 Shop Shark | | Shop Shark Joined: Jul 2011 Posts: 257 | So I picked up my driveshaft from that local company and it looks Sweeeeeet. But after all of this discussion I have another question. What kind of truck/application was this SM420 were it had a bolted on carrier for the u-joint apposed to a normal slip yoke style. Was it out of a heavy truck, a Napco......? | | | | | Joined: May 2005 Posts: 8,878 . | | . Joined: May 2005 Posts: 8,878 | All of the SM420's I've seen have a fixed yoke with exception of the enclosed driveshaft version but that's a different critter altogether. | | | | | Joined: Sep 2011 Posts: 1,456 'Bolter | | 'Bolter Joined: Sep 2011 Posts: 1,456 | All of the SM420's I've seen have a fixed yoke with exception of the enclosed driveshaft version but that's a different critter altogether. X2
BC 1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc 1949 GMC 250 project in waiting 1960 C60 pasture art Retired GM dealer tech. 1980 - 2022 | | | | | Joined: Jul 2011 Posts: 257 Shop Shark | | Shop Shark Joined: Jul 2011 Posts: 257 | That's comforting, so a slip spline driveshaft is a common thing? Thanks for the replies. | | | | | Joined: Jul 2005 Posts: 946 'Bolter | | 'Bolter Joined: Jul 2005 Posts: 946 | My NAPCO has three drive shafts with slip splines. Over greasing them gets you a nice spray of grease all over the bottom of your truck. | | | | | Joined: Jul 2011 Posts: 257 Shop Shark | | Shop Shark Joined: Jul 2011 Posts: 257 | So My Driveshaft saga continues. I went to install the new driveshaft today and the u-joint end caps on the rear of the shaft are too big. Called that shop, they asked me to remeasure the yoke and that the dimension should be 1 1/16 and 3 1/4. I did and my measurements were right on the money. I even took and old u-joint end cap and fit it into the yoke, a perfect fit. Take that same end cap and put it up against the rear end cap of my new driveshaft and sure enough the new one was bigger. They admitted the mistake and are going to swap it out tomorrow. If there is one thing I have had to learn with this truck restoration, it's patience. It's not something I'm good at, but I'm getting better | | | | | Joined: Jul 2005 Posts: 946 'Bolter | | 'Bolter Joined: Jul 2005 Posts: 946 | It's a long rough road to Patience Street. | | | | | Joined: Jul 2011 Posts: 257 Shop Shark | | Shop Shark Joined: Jul 2011 Posts: 257 | It's a long rough road to Patience Street. Tell me about it. Update: Took driveshaft down to shop. It ended up being that the tech put the wrong sized end caps on the u-joint. Simple swap to a smaller size and it's all good. Installed drives shaft last night, fits like a glove. Now it's on to the exhaust. | | | | | Joined: Feb 2008 Posts: 217 Shop Shark | | Shop Shark Joined: Feb 2008 Posts: 217 | The tranny you have described sounds like a Hotchkiss drive design. Yes that's the name. 4 speeds came in two designs according to the manual. The type that receives the internal u- joint of the torque tube and the design that I have and you have with a yoke or half a yoke out the back of the tranny.
I too had to get a drive shaft made. Counter guy said this was a common build for 4 wheel drives and such. They just put the slip yoke on the other end that connects to the rear end.
Rick......... | | | | | Joined: Jul 2011 Posts: 257 Shop Shark | | Shop Shark Joined: Jul 2011 Posts: 257 | | | |
| |