[blaykepepper04]

I just bought a second hand Jimny (01 Model) and there are a few issues with it.
The main of these issues being a very significant clunk or grinding sound when taking off and loading the driveshaft.
After further inspection i've found that whilst loading the driveline with the brakes on the driveline to the rear diff will spin and make a grinding sound even though the wheels are stationary.
Would this issue be the diff itself or something to do with the axle gearing?
Any help or ideas would be greatly appreciated.

Cheers,

Blayke

[zooker]

Sounds like a busted diff

[fordem]

blaykepepper04 wrote:

Would this issue be the diff itself or something to do with the axle gearing?

Either way, it doesn't really matter - if you've broken anything in the differential, the probability of "shrapnel" getting in between the crown wheel & pinion and causing damage is very high - you're going to need to pull the third member to find out what's what - if you're really lucky, it'll be a broken half shaft

What puzzles me is how you got the car home - if there's enough "slip" in there to allow the driveshaft to rotate without the wheels moving, I would expect the weight of the vehicle alone (meaning brakes not required) would prevent movement.

[blaykepepper04]

So far I have pulled out both axle shafts and dropped the diff oil which were all in normal condition. This makes me thinkn the problem is going to somewhere wherethe driveline joiuns the diff?

[Gwagensteve]

Are you still confident that your initial diagnosis that the rear driveshaft is turning but the wheels aren't?

[blaykepepper04]

Yes, I had a mate in the car whilst i was watching from underneath.

[fordem]

Based on your diagnosis that the rear driveshaft is turning and the wheels aren't - now that you've pulled the axle shafts and they are intact - it's time to remove the third member.

[blaykepepper04]

Thanks for that, i pulled out the third member and the diff itself looks completely fine, the teeth are all in perfect condition. Having said this i’ve never pulled a diff apart before so the problem could still be deeper inside. Any ideas now?

[fordem]

Attachment:

SN413_RD.JPG

The image above is an SN413 Jimny rear differential - the "cluster" of six gears at the top is the actual differential and they are housed in a cylindrical housing (18 & 20), so you can't really see them until you disassemble the unit.

At this point, if the axle shafts are OK, and the splines not damaged, my guess is the cross pins (14 & 15) are broken.

Maybe this is a good time to mention this - before you pull the third member apart - adjusting the backlash requires tools & experience - maybe a good used third might be the way to go. Maybe a good time to fit a locker (if they're available to fit the Jimny)

[blaykepepper04]

Thanks heaps for that diagram that’s super handy, i did have it disassembled part way and i could see that the pins were like they were in that diagram. Would it be worth shopping around for a new diff and just replace the whole thing at this point?

[Gwagensteve]

Not until you've determined that the diff is at fault.

I'm still struggling to work out what's going on.

If what you're reporting is accurate, the car could only drive in 4WD - it wouldn't be able to drive in 2WD. Is this the case?

The axles and diff appear "normal" which, as Fordem points out would mean the only possible failure would be broken cross pins. This isn't a common failure and I would have thought there would have been loads of debris in the oil/on the drain plug.


Was there much/any metallic debris in the bottom of the housing when you pulled the third member out?

What happens if you put the axles into the diff centre and turn the pinion flange? If it's cross shaft failure, the axles should stay still as the diff centre turns.

[Gwagensteve]

Alternatively, clamp the third member in a vice and put the axles in. With the pinion flange locked off, insert both axles, and attempt to turn one. The other axle should turn backwards. If it doesn't turn, or turns in the same direction the failure is inside the diff, cross shafts/spider gears or a side gear.

[blaykepepper04]

Trust me you aren’t the o lot one struggling, when i first lifted up the rear of the car so both wheels were in the air i turned one and the other turned in the opposite direction. When i removed the third member there was no metal shards or any debris and when i dropped the oil from the diff there was nothing in the magnetic bung. Would it be helpful if i could get a video of what the car is doing so that way it could make more sense?

[Gwagensteve]

Stripped/loose pinion flange?


I don't think you've answered if the car drives in 2WD.

[Joe]

Gwagensteve wrote:

Stripped/loose pinion flange?

This would be my guess if the oil has come out clean, was this happening when you bought the car? Maybe the seller put fresh oil in before you bought it?

[blaykepepper04]

Oh yeah sorry, it drives in 2wd fine except for the clunking and grinding sound. I actually drove it home from the guys place. So it’s still drivable but obviously not right. It does have quite a bit of suspension lift as well, would this have anything to do with it?

[Gwagensteve]

Ok. So if the driveshaft can turn when the wheels aren’t, then I don’t see how the car can drive fine.
My first thought was that the CV joint has failed at the back of the transfer case, but that would mean the driveshaft wouldn’t turn.

If it’s not a loose/chewed out pinion flange, we’ve exhausted all options. You need to go back over everything carefully and see what you’ve missed or alternatively double check the diagnosis that “the driveshaft is turning and the wheels aren’t”

I believe the most likely issue is actually a broken pinion gear but that can be hard to spot.

[fordem]

Surely a broken pinion gear would result in ...

a) damage to the ring gear
b) the vehicle not moving in 2H

What's the possibility of a dishonest seller rewiring the 2H/4H shift mechanism (does an 01 Jimny use the pushbuttons or a stick on the transfer case) so it's actually in 4H so it's operating as a front wheel drive vehicle?

[Gwagensteve]

Yes and maybe. I’ve seen plenty of damaged ring and pinions where the car drove.

The problem is still the idea that if the driveshaft is turning and the back wheels aren’t there’s significant mechanical damage in the diff/axles. It’s impossible for the driveshaft to turn and the wheels to not turn without breakage, which would leave some evidence. That’s why I asked if the OP could set it up on the bench and confirm what’s turning with what

TBH I think the driveshaft not turning with the wheels is a red herring and the grinding etc is coming from somewhere else.

[blaykepepper04]

It uses a stick but i know that the car is using 2H as there is another small issue in the transfer case when the car is in 4wd. I will put everything bacl together and link a video of whats going on with the driveline. Even though i pulled everything apart im not 100% sure what everything should look like so something could be broken/worn such as the pinion gear. Having said that, I also think that with the grinding that ive caused in the time i've had the car there would still be some form of residue due to the damage caused even if the seller had replaced the oil and cleaned it before sale.

[blaykepepper04]

I have decided to replace the transfer case with a second hand one, when i bought the car the seller said there were issues with the transfer case so ill replace it and see if that fixes the issue. If that doesnt then we can keep troubleshooting from there. Thaks heaps for all the ideas and thoughts.

[fordem]

IF you can see the rear driveshaft spinning and the rear wheels not moving - replacing the transfer case is not going to fix the problem.

Remember, we are not there seeing what is happening, we are going based on what you tell us, there is a certain amount of speculation going on, because some of what you say just sounds wrong.

Personally, and this is based on what you've told us, I would rather spend the money on a known good used rear axle/third member, but it's your money.

[Gwagensteve]

Take on board what Fordem is saying.

We're trying to help but with no photos or video, we're relying on your description.

If the driveshaft is spinning and the wheels aren't turning, the goal, when you had the rear axle assembly completely apart, was to find the cause of that, because it's 100% in the axle/differential assembly. Putting it all back without finding it and then changing the transfer case is completely futile, the problem will still be there.

Everything we are trying to suggest depends on your statement that the driveshaft is spinning and the wheels aren't turning. Everything else you've offered contradicts that.
The car drives
The differential is free of wear or damage
The axles are free of wear or damage
The differential operates normally (i.e one wheel turns forward and one backward when the pinion is stationary)

You'll note, we're not interested in the noise - that may or may not be anything to do with the problem, and could be a complete red herring. At this stage, the only thing that's important is that the driveshaft is spinning and the wheels aren't. Once that's resolved, we can look at other issues.