1980 k10 drive line parts. 1 year only????

[Jaysonb]

My truck is an 80, but the frame and running gear are 79. My np203 is toast, so I got a np205, and drive shafts out of a 80 parts truck I have. While I am waiting for the rest of the parts to rebuild the np205, I am cleaning and painting everything. I worked on the rear drive shaft tonight, went to the parts store to get new u joints, and they tell me they are both the same size, well I had just pounded the old ones out, and the u joint at the slip yoke is bigger than the one at the axle. Every where I look online says they should be the same! The front driveshaft from the parts truck is shot, so I look that up, same drive shaft listed as the one I just bought for the 79 with the np203, but the one off the parts truck is at least a few inches shorter!!!! This 80 parts truck is bone stock, I just can't believe that I'm having such a hard time finding the right parts for it.

[Your41Plague12]

I believe 1980 was the only GM NP205 produced with a slip yoke rather than a fixed yoke. That's what I've read at least, and that could be wrong. But that may have something to do with it if it's true.

[Jaysonb]

I hope it ends up being worth the trouble in the long run. When I was doing research about fixing my np203, I read a lot of people saying dump the 203 and throw in a 205. There must be a lot of guys with money to throw around, its costing a small fortune to make the swap.

[cadillac_al]

I'm the only 203 lover and I always get 10-11 mpg. I doubt those part timers save much fuel at all. I hope you like yours after all this expense.

[SilverMiner]

Jasonb - I just went out and check my 1980 K10 Suburban, and in fact the u-joint on the slip yoke is larger than the u-joint on the rear. I'm glad you pointed that out, or I would have had to rely upon my parts guy to set me straight because I never would have expected it.

My drivetrain is original at the moment with the TH350C lockup transmission and the NP205 t-case. Like cadillac_al, I'm an NP203 lover as well, and actually have a TH400/NP203 combo sitting in my shop ready to go should my rig ever require it. One thing holding me back though is the driveline changes. I've owned quite a few square-body trucks and was quite surprised to encounter the slip yoke. 1980 was a one-off year in a number of ways, and not all of them good.

[Jaysonb]

I didn't mind the np203 at all, the one in my truck had the weaker stamped steel diff housing in it, and a part time kit in it, the teeth on the diff housing wore off, or sheared off, I found one of the heavy duty cast diff housings and put that in, but there was a lot of metal in the case, and something else must have got taken out. The 203 looked a lot tougher to rebuild, with a lot less info available on the process. The np205 I have wasn't in the greatest shape either. The front drive flange was loose, so that took out the flange, and the front output shaft, and the adapter sleeve was pretty wore, so I had to replace that, and the input shaft, add to that gaskets and bearings and I have about $600 into this thing. It should last the life of this truck now though. I just bought a new front driveshaft about a month ago, its a few inches to long, but I can have it shorted and balanced for about $85. I should have it all wrapped up minus the front shaft tomorrow afternoon. Not looking forward to wrestling that heavy pig out of the truck though!!

[KrazyRay]

I can verify that I came across a slip yoke 205 in a 1980 K10 that I parted a while back.

[Jaysonb]

I figured out that the front u joint is a 1350, and the rear is 1310. Its funny, I called a few of the parts stores in town, none of them can look up u joints like that, they need the make and model. I miss the days when there might be a chance the old parts guy behind the coucounter might know the parts better than me.

[gmachinz]

I hear ya. Back when I started out behind a parts could we would deal with a lol of racers. They'd need ujoints for a TH400 trans yoke and a 9" Ford rear end from a truck. We'd just go grab the matching Spicer conversion ujoint. We all memorized a lot of oddball parts like that.
Or how about watching a parts guy (like myself back in the day) helping grab fittingsbfor a customer right off our wall with the customer saying something like "I need 4 90-degree -10 full flow elbows, 2 -10 straights, a -10 to -8 flared union reducer......" and I'd be grabbing the Aeroquip parts as he was rattling off what he needed.
Ah....the good ole parts days.....