Problems front axle
- Thread starter Steven28
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There's no grease around the axle shaft coming through from the birfield.
That gap should be wet with MOLY grease from the Birf joint. The axle will naturally fall to the bottom by gravity in the un-assembeld condition, the drive flange holds it centered. When you grab the splines and move the axle shaft around there should be a wet-greasy "slick slick" sound.
How much tension is it under? Can you lift it to the top of the spindle hole?
That gap should be wet with MOLY grease from the Birf joint. The axle will naturally fall to the bottom by gravity in the un-assembeld condition, the drive flange holds it centered. When you grab the splines and move the axle shaft around there should be a wet-greasy "slick slick" sound.
How much tension is it under? Can you lift it to the top of the spindle hole?
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Run dry would be my guess. The grease level in the knuckle needs to be maintained to lube the bushing.
I drew up a sketch of what effects alignment of the two axle shafts and what would cause the outer axle to rub the spindle bushing.
A bent axle housing would cause the inner axle to rub the inner seal, and if bent enough to touch the inside of the axel housing then it would cause the binding. One would think there would be a pretty good tell-tale-mark from a bump that hard. and the inner axle seal would be blown. If it was just a little bent then the trunnions would maintain aliment of the bushing and the wheel bearing center line.
If you're not hearing a rubbing/scraping sound from the axle housing, a more likely culprit is a bent spindle. A bent spindle would force the misalignment of the wheel bearing center line to the bushing center line.
I missed the age of the truck if you told us, another possibility would be an offset of the center line of the spindle side and axle side of the Birfield housing, the older trucks need shims under the trunnion bearings to maintain this alignment. This would also manifest a secondary problem of a blown inner axle seal.
How's the inner axle seal?
A bent axle housing would cause the inner axle to rub the inner seal, and if bent enough to touch the inside of the axel housing then it would cause the binding. One would think there would be a pretty good tell-tale-mark from a bump that hard. and the inner axle seal would be blown. If it was just a little bent then the trunnions would maintain aliment of the bushing and the wheel bearing center line.
If you're not hearing a rubbing/scraping sound from the axle housing, a more likely culprit is a bent spindle. A bent spindle would force the misalignment of the wheel bearing center line to the bushing center line.
I missed the age of the truck if you told us, another possibility would be an offset of the center line of the spindle side and axle side of the Birfield housing, the older trucks need shims under the trunnion bearings to maintain this alignment. This would also manifest a secondary problem of a blown inner axle seal.
How's the inner axle seal?
LINUS
Waiting for the Great Pumpkin
Having bent a housing like @Pin_Head guessed, I’d pull the shaft & see if you chewed any splines on the inner shaft going into the diff.
Are you leaking and diff fluid from the 3rd member flange?
If you drain the diff fluid (crack the fill plug so you know you can refill first) - do you get metal shaving like it’s brown metallic paint? Or even just a few big metal chunks?
I chewed the inner shaft splines, cracked the drive cuff of the PS diff, ate the spindle on the bronze bushing from the effect of the initial bend & subsequent driving ~800 or more miles getting parts. It made birf soup real quick (<100mi) - since the bend make the shaft seal far from sitting centered even that close to the drive plate.
I ate some teeth on the spider gears, but that was that drive cuff metal getting chewed up before it settled in the bottom of the diff bell.
Luckily I’d slated retrofitting e-locker 3rds on hand, so when my destroyed open 3rd came out, I just sold it as a damaged core to a guy who knew ahead what was going on.
I didn’t realize I bent the whole housing until I got everything apart & then luckily just eyeballed I had a 1/2” bend in the housing that I verified with a pair of 24” carpenter squares & tape measure.
Housing was still on the vehicle, lucky I have a hoist so I could see the issue - if I knew it was bent I’d have taken the shell & all whole & reassembled on the bench like I did with all the parts for the new shell.
Christo always commented they bent easy & I know the spot I did it on, I was amazed how I did it - I wasn’t trying to do KOH -type stuff, just a hard drop into a hole that sucked a wheel & a large rock landed just next to the pumpkin / diff housing. I was lead & spotter & I both thought the grass (hole) was just short. It hid a hole big enough to slam to axle shell & rob my wallet of ~$1500 by the time I had paid tax & everything. Not including all other parts listed.
As an aside, I prefer the brass/bronze bushing spindle to the newer needle roller bearing one - even though I ate mine, they seem more robust IMO. I believe both styles are available, IDK why the needle bearing was used. 2 more bearings to fail IMO.
Esp if any of the symptoms I listed, if you’re not on a hoist figure out a way to verify your housing is true.
Are you leaking and diff fluid from the 3rd member flange?
If you drain the diff fluid (crack the fill plug so you know you can refill first) - do you get metal shaving like it’s brown metallic paint? Or even just a few big metal chunks?
I chewed the inner shaft splines, cracked the drive cuff of the PS diff, ate the spindle on the bronze bushing from the effect of the initial bend & subsequent driving ~800 or more miles getting parts. It made birf soup real quick (<100mi) - since the bend make the shaft seal far from sitting centered even that close to the drive plate.
I ate some teeth on the spider gears, but that was that drive cuff metal getting chewed up before it settled in the bottom of the diff bell.
Luckily I’d slated retrofitting e-locker 3rds on hand, so when my destroyed open 3rd came out, I just sold it as a damaged core to a guy who knew ahead what was going on.
I didn’t realize I bent the whole housing until I got everything apart & then luckily just eyeballed I had a 1/2” bend in the housing that I verified with a pair of 24” carpenter squares & tape measure.
Housing was still on the vehicle, lucky I have a hoist so I could see the issue - if I knew it was bent I’d have taken the shell & all whole & reassembled on the bench like I did with all the parts for the new shell.
Christo always commented they bent easy & I know the spot I did it on, I was amazed how I did it - I wasn’t trying to do KOH -type stuff, just a hard drop into a hole that sucked a wheel & a large rock landed just next to the pumpkin / diff housing. I was lead & spotter & I both thought the grass (hole) was just short. It hid a hole big enough to slam to axle shell & rob my wallet of ~$1500 by the time I had paid tax & everything. Not including all other parts listed.
As an aside, I prefer the brass/bronze bushing spindle to the newer needle roller bearing one - even though I ate mine, they seem more robust IMO. I believe both styles are available, IDK why the needle bearing was used. 2 more bearings to fail IMO.
Esp if any of the symptoms I listed, if you’re not on a hoist figure out a way to verify your housing is true.
This is a little off subject, and maybe some of our Mud parts experts can answer this question. In the top photo the rotor splash shield has cooling vents cut in to it. Were those cooling vents part of an " brake cooling package" for trucks with the factory tow package? Or were those vents standard equipment on post 1994 models? The reason i ask, I've got a 1994, and my trucks brake splash guard dosen't have those vents.
