Knocking only in 4wd

[T0mmyM]

Hello im new to 4x4s, i have just bought a jx vitara 1.6 8v manual. It has a body lift and spring spacers, diff drop brackets with polymounts. I have just fitted reconditioned freewheeling hubs, i have changed the front diff casing as it was broken (diff looked in good condition) but i still have a knocking which previous owner also had. I should mention the shafts all looked ok but they do sit at quite an angle even with the diff drop brackets.
The problem i have only seams to be in 4wd, when in 2wd with the free wheeling hubs still in the locked position the knocking stops. If i am right this tells me its a diff/diff ratio problem? I am no mecanic but as said above diff looked in good condition (no broken/worn bits/turned smoothly)
The previous owner has said with more weight on the front the noise stops, i am yet to try this.
I have had the anus off all fours and in first gear but all seamed fine and no knocking when jacked up.
Ive read a little into transmission wind up as i have not yet taken it off road just forwards and backwards a few feet on concrete.. Would wind up cause these symptoms or could it be mahbe incorrwct ratios between front and rear diffs?
Any info/help on what to try next would be much appreshiated
Cheers

[Anton]

Have you checked all of your UJ's for play?


Click Here for Youtube Video



If it's your UJ's, it'll be the front ones specifically causing the problem.

[T0mmyM]

Ujs seam ok little bit dry no unusual movement though, sounds like its coming from the front more than underneath, weird thing though the noise has switch sides since i put it all back together

[Anton]

If your driveshafts are at a steep angle, I suppose it *could* be your birfield joints (I've had a "clicky" birfield in the past) but it would be very unusual for it to swap sides like that - if one side is clicking, then it shouldn't stop clicking - and the reason I didn't mention it before is that it only happens when on full lock or near full lock, and it should happen in 2wd if the hubs are engaged.

Still, with a steep angle on your shafts, it could still be worth looking at.

Beyond that, my knowledge of Vitaras is limited, I've never owned one. I can only suggest things that are pretty generic to all 4x4's. Sorry I couldn't be more helpful, buddy.

[T0mmyM]

Cool thanks ill take a look through the week. Yeah very strange that its swopped sides maybe that too points towards diff. Could a ruined diff only be noticable under load?

No problem at all dude this 4wd malarky is all new to me so every little helps

[Anton]

I'm used to a solid front axle, you have IFS. So there's a lot going on in your setup that isn't even there in my setup...

As for the diff, I suppose a bearing could be going? Usually that's not a knocking sound, but it could be causing the backlash or something to be off in the diff...?

Or you may have a chipped tooth on the crownwheel?

I would have thought that either of those would cause sounds with or without load, but it does depend on which face of the tooth is chipped on the crownwheel. Do you get the noise when you're in reverse?

[T0mmyM]

Im guessing a solid axle is similar setup to the rear?
Yeah its the same in reverse
There is slight play in the diff when i move the shafts im not sure how normal that is

[Anton]

There should be a tiny amount of play in the diff, that's normal. It's called the "backlash", and it should be *really* tiny, but noticeable when you wiggle the input pinion of the diff by hand. You should be able to feel it, but barely see it. If it's got a lot of wiggle, then there's more than normal backlash going on and your diff is probably in need of new bearings/a full rebuild.

The amount of wiggle should be a few hundredths of an inch. I can't remember the exact Suzuki specs, but it's a minute fraction of an inch at the crownwheel. You should be able to hear it, feel it, but not really be able to see it move - it should be barely noticeable to the eye, if at all.

Ignore the first 6 seconds of this video:


Click Here for Youtube Video

[T0mmyM]

When i had the diff apart im pretty sure there was a fair amount of movement in pinion gear, when i twist the shafts i can hear the gears knocking one side to the other, worse on drivers side.
Really helpful video they dont seam too complicated.
I think ill buy a second hand diff see where that gets me?

[Anton]

Pull your current one first, and have a good look inside. Check the backlash with a dial indicator if you can, check all the bearings for play.

If you don't mind losing 4wd for a while, you could take the front prop out, take the halfshafts out and run around with a 2wd vehicle for now, until you're ready to pull the diff and check it out properly. No point buying a new diff if you can't be sure that's the problem.

On the other hand, if you can get one for pennies, then go for it. But don't pay real money for one until you're certain that's the problem.