Lately my truck has been having a noticeable rumble/vibration at 30-65 mph..
I assumed it might be the tires,they are just crappy used ones,and the fronts are a smaller size by an inch.and "C" rated,not "E" rated like the rears..
I also put decent shocks up front and thought maybe they transmit more road noise than the dead ones I removed...but I didn't notice the vibes right away after replacing them..
But to be sure,I crawled under it today and looked everything over..as usual,I saw nothing I liked...just more things getting ready to fail and cause more grief ..
I checked the diff gear oil level and the transfer case,both are a bit less than full,but not low enough to do any harm--only the transfer case leaks a little,and I've only had to add a quart at most after a year...rear diff may still have the 1982 oem lube in it for all I know..looks OK,not milky ..
I've never had to change the rear u-joints,but they felt tight and have not made that tell tale squeaky chirp noise on take offs,so I assumed they were OK,and I went to the front shaft--and found the joint at the front diff was wasted--no needles in 2 cups,and I can move it up and down about 1/4" or so...
..
But the CV joint and u-joints at that end are still nice and tight..
Then I looked at the passenger side axle joint,that is wasted as bad or worse..
So,I guess that explains the vibes I'm feeling..
I think I have a rebuilt front shaft that may fit this truck,but I am just going to put one new u-joint on the existing one and run it..
My NP-208 has always powered the front shaft,even in 2wd--I tried adjusting the linkage as instructed by service manuals,and it was spot on,and I couldn't move the link on the case any further towards 2wd with the linkage off,so I assume something internal is "stuck" in 4wd...
For all I know someone could have had it apart and screwed with it,but it doesn't appear molested--no RTV on the case halves ,etc..
For the past 15 years I've just unlocked the hubs and drove it like that,and let the front drive shaft and axles spin..more than one mechanic I've talked to, said the u-joints fail faster on part time 4x4's from not getting spun,letting them sit seizes them up faster--so the grease dries up and the needles rust..
I tend to agree,I had a NP-203 truck I never changed any u-joints on,and I put a lot of miles on it..while my K5's and 1/2 ton pickups all needed new axle joints every 4 years or so..(usually the drivers side went first)..always due to rust too--no matter how well I greased them...
I've never broken a U-joint,even plowing with axle joints that were devoid of ANY needle bearings!..some were so badly worn,the cups almost wore thru,and the cross would have chowed the yokes to hell...but I didn't go full throttle either,I babied them..
I had replaced the drivers side axle joint a couple years ago (in December,as snow started to fall)..I checked the right side then, and it was still tight ..
So now I have to replace both of those--I hate doing axle joints the most..my yokes on the drivers side axle shaft and stub shaft were rusted so thin where the u-joint cups go,I feared I'd ruin them pressing the u-joints out and the new ones in..I used a light foot on the throttle plowing ever since..
I'm betting the yokes on the right side are no better..
I found some spare front axle shafts from 1/2 tons I had,but I'm pretty sure they are from pre-77 Dana 44's...my '82 truck has the GM corporate 10 bolt front diff...so I doubt they would fit or work..(figures)..hoping I can get a u-joint in them without harming them..
Of course,I have spare u-joints on hand for the rear shaft,but none for the front diff one or axle joints..so I'll have to buy them....
...just like I have over 175 V belts in my garage,all the wrong sizes for anything I am repairing,naturally..nothing irks me more than having a garage full of new & used parts,that wont work on the vehicle I'm repairing ,and having to go buy them..
I assumed it might be the tires,they are just crappy used ones,and the fronts are a smaller size by an inch.and "C" rated,not "E" rated like the rears..
I also put decent shocks up front and thought maybe they transmit more road noise than the dead ones I removed...but I didn't notice the vibes right away after replacing them..
But to be sure,I crawled under it today and looked everything over..as usual,I saw nothing I liked...just more things getting ready to fail and cause more grief ..

I checked the diff gear oil level and the transfer case,both are a bit less than full,but not low enough to do any harm--only the transfer case leaks a little,and I've only had to add a quart at most after a year...rear diff may still have the 1982 oem lube in it for all I know..looks OK,not milky ..
I've never had to change the rear u-joints,but they felt tight and have not made that tell tale squeaky chirp noise on take offs,so I assumed they were OK,and I went to the front shaft--and found the joint at the front diff was wasted--no needles in 2 cups,and I can move it up and down about 1/4" or so...
..But the CV joint and u-joints at that end are still nice and tight..
Then I looked at the passenger side axle joint,that is wasted as bad or worse..

So,I guess that explains the vibes I'm feeling..
I think I have a rebuilt front shaft that may fit this truck,but I am just going to put one new u-joint on the existing one and run it..
My NP-208 has always powered the front shaft,even in 2wd--I tried adjusting the linkage as instructed by service manuals,and it was spot on,and I couldn't move the link on the case any further towards 2wd with the linkage off,so I assume something internal is "stuck" in 4wd...
For all I know someone could have had it apart and screwed with it,but it doesn't appear molested--no RTV on the case halves ,etc..
For the past 15 years I've just unlocked the hubs and drove it like that,and let the front drive shaft and axles spin..more than one mechanic I've talked to, said the u-joints fail faster on part time 4x4's from not getting spun,letting them sit seizes them up faster--so the grease dries up and the needles rust..
I tend to agree,I had a NP-203 truck I never changed any u-joints on,and I put a lot of miles on it..while my K5's and 1/2 ton pickups all needed new axle joints every 4 years or so..(usually the drivers side went first)..always due to rust too--no matter how well I greased them...
I've never broken a U-joint,even plowing with axle joints that were devoid of ANY needle bearings!..some were so badly worn,the cups almost wore thru,and the cross would have chowed the yokes to hell...but I didn't go full throttle either,I babied them..
I had replaced the drivers side axle joint a couple years ago (in December,as snow started to fall)..I checked the right side then, and it was still tight ..
So now I have to replace both of those--I hate doing axle joints the most..my yokes on the drivers side axle shaft and stub shaft were rusted so thin where the u-joint cups go,I feared I'd ruin them pressing the u-joints out and the new ones in..I used a light foot on the throttle plowing ever since..
I'm betting the yokes on the right side are no better..
I found some spare front axle shafts from 1/2 tons I had,but I'm pretty sure they are from pre-77 Dana 44's...my '82 truck has the GM corporate 10 bolt front diff...so I doubt they would fit or work..(figures)..hoping I can get a u-joint in them without harming them..
Of course,I have spare u-joints on hand for the rear shaft,but none for the front diff one or axle joints..so I'll have to buy them....
...just like I have over 175 V belts in my garage,all the wrong sizes for anything I am repairing,naturally..nothing irks me more than having a garage full of new & used parts,that wont work on the vehicle I'm repairing ,and having to go buy them..
,was nice to look at,but extremely distracting--and quite useless as far as getting me any answers..she typed on her computer for like 10 minutes,while talking on her cell phone to the other woman employee who "normally takes care of these things",that was somewhere else on her break..
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