I ran a 1inch d-shaft spacer with an 8" lift and the stock front shaft was fine. When I lowered it down to 4-5" of lift I took the spacer out and it rubbed the crossmember. I just ground the casting on the cv smooth and it was fine.
CK5
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'90 K5 - The Nevada Blazer [Post 1437: School me on alternators)
- Thread starter colbystephens
- Start date
Maybe I am grinding on the crossmember. I hadn't really considered it. Now I'm real curious. I'd been expecting it to be specifically the CV, but I've been wrong before... and probably most of the time. 
Had to drive the truck for work today and I quick looked under there to check out the crossmember on my way out. It's terribly close. I hadn't really noticed it before, because I was looking more at the stock skid plate. With the kind of noise I'm getting, it would make sense that it would be from the crossmember. It's like a repeating "thwack thwack thwack." Which makes sense with the CV hitting since there's gaps between the ears of the CV. I'm going to try to clearance that sucker on Friday morning and see if that fixes it. I have some mild wheeling Friday and Saturday that both involve VERY steep hill climbs, so I want this taken care of before hand.
Thanks for all the encouragement and ideas!!!
Thanks for all the encouragement and ideas!!!
That is a possibility, so clearance that first and then if you still have the problem, look into clocking the tcase down.
I know everyone is always doing the opposite but in your case I think it will be the cheapest option.
Yep, I'm thinking clocking would do the trick too.
That's a pretty good price. I wonder about clocking the t-case upwards, if that would fix my problem? It'd be an upgrade and a fix in one fell swoop! We'll have to see what we find when I flex the truck out on Friday morning.
We'll have to see what we find when I flex the truck out on Friday morning.
Bah, you don't need to clock it. There are plenty of rigs around your height that make it work. Pull the drive shaft and grind the casting all smooth on the outside of the cv. You'll be able to tell if its been hitting. Mine had a shiny spot on the casting.
X2 Or you could clearance and reinforce the crossmember, or space the case up half and inch.
Clocking the case up or down would create another can of worms with ground clearance or driveshaft angles again.
But it would be cool.... Just sayin. The more I think about it, the more i'm inclined to believe that this is related to the crossmember, so I'm glad for what I think will be an easy fix.
Also, as an aside, I'm about at my full-break in for the rear gears. So, I picked up gear oil and a gasket for the 14 bolt. Also, it's time for trans/t-case service and an oil change. So, I'll be replacing all the oil in the truck except for the front axle shortly, and installing a new transmission filter. That should give me more piece of mind.
The more I think about it, the more i'm inclined to believe that this is related to the crossmember, so I'm glad for what I think will be an easy fix. Also, as an aside, I'm about at my full-break in for the rear gears. So, I picked up gear oil and a gasket for the 14 bolt. Also, it's time for trans/t-case service and an oil change. So, I'll be replacing all the oil in the truck except for the front axle shortly, and installing a new transmission filter. That should give me more piece of mind.
In your wheelin, do you ever do any water crossing or water traps? If so you should be changing you gear oil a lot more often.
There's very few water crossings in NV. 
Also, this is the 500 mile gear oil change required for proper gear break in. The front is going to take forever to get broken in, so I'm not going to bother changing it for a few months.
Also, this is the 500 mile gear oil change required for proper gear break in. The front is going to take forever to get broken in, so I'm not going to bother changing it for a few months.
That's a pretty good price. I wonder about clocking the t-case upwards, if that would fix my problem? It'd be an upgrade and a fix in one fell swoop!
No, for your problem you need to clock it down, which as i said is opposite of what most like to do.
If you clock it up, you aggravate your problem, unless your problem is the crossmember. Then you don't need more than a grinder or a plazma cutter to the cross member.
Well, I've found the problem(s)! I'm stoked. I had a few extra minutes tonight, so I went up to the Church parking lot and flexed out on a big boulder. I could hear it grind as I slowly inched my way up the rock. I put it in 2wd, parked it, and unlocked the hubs. The driveshaft spins freely by hand. I wasn't at completely full droop on the passenger side, but certainly more droop than I'd effectively have going uphill. So I looked closer and could see the grind marks on the cross member, and the CV is about 1/8" away from it. So, apparently under load my transfer case is bearing down towards the ground just a bit, and that allows the CV to clack against the crossmember.
So I'm quite relieved to know I don't have an expensive new front shaft be the only fix! So Friday morning I'll clearance the crossmember. My next question is, does this indicate a bad transmission mount? I'm thinking yes. This one has 200,000 miles on it, so it would make sense. When replacing those mounts, do I need to also replace the engine mounts at the same time? What material would you go with? I know both engine and trans. mounts need to be made from the same material.
Thanks to all who are helping me through this stuff.
I know this is sort of a noob problem! 
So I'm quite relieved to know I don't have an expensive new front shaft be the only fix! So Friday morning I'll clearance the crossmember. My next question is, does this indicate a bad transmission mount? I'm thinking yes. This one has 200,000 miles on it, so it would make sense. When replacing those mounts, do I need to also replace the engine mounts at the same time? What material would you go with? I know both engine and trans. mounts need to be made from the same material.
Thanks to all who are helping me through this stuff.
I know this is sort of a noob problem! 
Colby, this happened to me and it was the same exact thing. The front driveshaft was binding and was hitting the crossmember. It did wind up being the trans mount. I didn't do the engine mounts when I did mine though...
I still think I'll clearance it though. That's a pretty tight margin, even if the trans mounts were new.
Yeah I would clearance it and change the mounts, tranny and engine.
I personnaly like the rubber because it makes the vibration of the drivetrain less apparent, but for best stiffness and durability I'd go with Poly.
Well, I've found the problem(s)! I'm stoked. I had a few extra minutes tonight, so I went up to the Church parking lot and flexed out on a big boulder. I could hear it grind as I slowly inched my way up the rock. I put it in 2wd, parked it, and unlocked the hubs. The driveshaft spins freely by hand. I wasn't at completely full droop on the passenger side, but certainly more droop than I'd effectively have going uphill. So I looked closer and could see the grind marks on the cross member, and the CV is about 1/8" away from it. So, apparently under load my transfer case is bearing down towards the ground just a bit, and that allows the CV to clack against the crossmember.
So I'm quite relieved to know I don't have an expensive new front shaft be the only fix! So Friday morning I'll clearance the crossmember. My next question is, does this indicate a bad transmission mount? I'm thinking yes. This one has 200,000 miles on it, so it would make sense. When replacing those mounts, do I need to also replace the engine mounts at the same time? What material would you go with? I know both engine and trans. mounts need to be made from the same material.
Thanks to all who are helping me through this stuff.
See no reason to freak out. Like I've been saying in this thread. I'd just pull the shaft and grind the casting on the CV with a flap wheel on a grinder and call it a day. You can remove a lot of material just rounding it up and it'll be fine.
I lowered my truck last minute before a trip to the dunes a few years back and threw it on the trailer. I got to Pismo and pulled off the trailer, aired down, kicked it in 4 and took off only to hear a horrible clunk/grind like you were describing. Soooo, I put it in 4 hi and went blasting across the dunes until it self clearanced.
I hit it with a flap wheel when I got home for good measure but it was pretty round already.
Soooo, I put it in 4 hi and went blasting across the dunes until it self clearanced.
I considered this too...
I'm leaning towards getting some 1/2" thick steel, cutting it down and drilling a couple holes to make a spacer and then put it in between the crossmember and the trans mount.
y5mgisi
1 ton status
I like that idea. I figured there could be no way that with a 4-5" lift you would be having driveline issues.
