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Getting a clunk in the driveline when power is applied and a vibration on coasting, so believe I need to replace the U-joints on my 77 F150 4x4, SWB, 351M, NP435, NP205. Got the shaft out yesterday and it's got the cardan CV joint that bolts to the transfer case output yoke. Then down to a slip yoke and U joint for the rear axle. Based on all of this, I believe I have identified the parts that I need for a rebuild. Want to go with sealed joints instead of greasable. What I have selected is three Dana/Spicer 51330X joints, and the 21355X centering yoke. Can someone be kind enough to confirm these parts numbers?
In my research, I believe I have answered my own question. Need to disassemble and measure to see if they are 1310 or 1330. All the normal suppliers have multiple offerings, and not a clear path to decipher what you actually need based on your truck. Hoping the sealed joints will keep me from having to get under the truck any more than I have to. They're also cheaper than the greased joints.
Hoping someone can give some advice on U joint selection part two, without another thread. Got the entire rear driveshaft stripped down, degreased, cleaned and painted. The fixed pin on the front of the driveshaft that mates into the centering yoke is in good shape. Nice and smooth with no gouges or pitting. When I disassembled the shaft, it had greasable U joints, and a greasable center yoke. The yoke had a metal ring around it, that I assumed was the remnant of a dust boot for the center yoke ball. From my reading (albeit mostly Jeep sites), it seems that with a non-greasable center yoke, the rubber seal is used, but with a greasable centering yoke it is not. Can anyone clarify on this application?
Second question. The rear end of the driveshaft is splined, that fits into a slip yoke. When I disassembled to remove the old dirt and grease, there appeared to be a blue plastic disk on the end with fingers that ran down the splines. It was severely disintegrated. At first I thought it was hardened or polymerized grease, but it was stiff plastic. Based on the fact that the end of the slip yoke being open, was this some kind of seal to keep the grease in the splines of the slip yoke? I have not found anything that looks like it. Obsolete?
Lastly, the seal on the output yoke on the NP205 is leaking. I removed the nut (found out it was a 1 1/8" after I had bought a 1 5/16" socket) and the output yoke cam out easily. It appears I need to remove the 5 bolts that hold the seal housing to the case, and remove and replace seal that way. I have seen a kit that included the nut and a rubber splined bushing/seal that I assume fits up into the yoke to keep oil where it's supposed to be. Read alot about this seal and leaks, mostly due to people running the wrong fluid in them. I assume mine had one, but I haven't looked into the yoke to see if it's there. Should I just go ahead and order this replacement nut and seal?
I'll muddy the water for you a little on Questions #1. When we rebuilt our driveshaft and CV yoke, we had the same question. Our new parts did not have a dust boot. I emailed Dennysdriveshaft shop with the question as to whether or not is was needed and the response was "not really"
Here are the emails:
My Question: I am rebuilding a double cardan cv joint on a 78 F150 4WD.
I have a new Moog 607 grease-able centering yoke. Do I need the rubber boot? I see it listed as part # 2-86-418.
I notice that it specifies use with non-grease-able yokes, but when I took the old one apart, the yoke has a grease fitting and there was an old ring still on the nipple that looks like the remnant of an old boot.
Thanks for any help/advice.
Reply: No you no longer need the boot.
At least I think this is what you are asking.
We did not worry about the dust boot. So far all is good. 3+ years running.
As far as the splined seal that goes inside the nut, I found them the cheapest on ebay
Thanks for the help. Exactly the info I was looking for on the output yoke nut and seal, and the cardan joint. I didn't get to fool with the truck last night. Been playing appliance repair man. Last week was the dryer belt, this week was the motor coupler in the washing machine. At least they were cheap fixes. Hope to get this thing back together soon.
Ha, the Financial Light gives me more money for parts! Got the output shaft seal housing off. As you can see in the picture the lower cut out has a deposit of very fine metal. I would assume this is normal for a truck with 127k on the odometer. Ordered the wrong output seal. National 473468 is too big for my yoke. Have to measure and reorder.
Edit: after cleaning, old seal is stamped National 470304
Edit 2: apparently the previous part number is obsolete. New number is Timken 473457. 1.825” output yoke with double Cardan. Was this factory ford? From what I’ve read, maybe, maybe not?
Be sure to check the surface on the shaft of the yoke where the seal rides for excessive wear/grooves. You may need to put a Redi-sleeve on it. I have found that the local parts stores sometimes have competitive prices with online sources for them.
I've had the seal housing and the output yoke in degreaser last night to remove the 40 years of dirt and grease. The yoke shaft appears to be in good shape. I could not feel a ridge or anything running my finger nail across it, after I removed the caked on deposits.
New seal should be here in the morning, along with another sending unit so maybe I can have an operational fuel gauge.
) and the output yoke cam out easily. It appears I need to remove the 5 bolts that hold the seal housing to the case, and remove and replace seal that way. I have seen a kit that included the nut and a rubber splined bushing/seal that I assume fits up into the yoke to keep oil where it's supposed to be. Read alot about this seal and leaks, mostly due to people running the wrong fluid in them. I assume mine had one, but I haven't looked into the yoke to see if it's there. Should I just go ahead and order this replacement nut and seal? 
