Loud Drive Train Noise from the Jimny

[Mike57]

I just posted this question on Auszookers but thought I might drop it into here as well.

I have a 2009 Jimny with manual transmission and the original electric transfer case. I had an air locker installed by ARB a few months ago and this problem may or may not be related to that.

On the last trip I did in the sand I noticed a very loud repetitive banging noise from the transfer case area when the drive train was under full load. I thought it was the exhaust hitting on something so yesterday I had the rear muffler replaced and some other work to make sure it was not the exhaust. I just went down to a steep hill nearby and did a hill start in 2 wheel drive. The loud chattering noise was still there, almost like a ratchet or a failed CV joint. If I use the handbrake on flat ground and take off in first gear it does the same thing. So it is related to loading up the drive train and I can rule out the front hubs, CV's or the front drive shaft.

In all other respects the car drives fine with no unusual noises or vibrations.

I felt all the universal joints and they seem to be solid. The car has only done 21,000 km.

I am thinking this must be the transfer case or the rear diff as I don't see this being a uni problem. What has me puzzled is that apart from when the drive train is under stress there are no other noises or vibrations. The noise certainly seems to be in the transfer case area and not down the rear.

I am out of ideas so if anyone has any thoughts I would welcome some fresh ideas. It is a VERY loud noise by the way and happens with or without rear diff lock engaged.

[gwagensteve]

Am I right that your model has a cv-joint style of thingy at the transfer end of the rear driveshaft? I think these can be quite pernickety. I think I'd remove the rear driveshaft and take it for a careful drive in H4 to see whether under the same load, the noise is still there.

If it is, then the problem is likely in the transfer or jackshaft.

If it's not, then it may be rear driveshaft (or diff) related.

Just something to check quickly before you spend more money/time on it.

Otherwise, have a really good look to check that the transfer mounts aren't broken. Could the transfer hit the floor if one if a mount failed?

Just some thoughts.

Steve

[Mike57]

Steve

It does have some sort of "CV type thingy" in the drive shaft rear of the transfer. From the Auszookers site the suggestion is a slipping (or I guess jumping) transfer chain. Your suggestion of converting to front wheel drive is a useful one. I will do some more research on it as well before pulling anything else apart.

Thanks

Mike

[gwagensteve]

Hmm, interesting.

If it's really loud, then it may well be chain slip. If so, it might be hard to prove by doing the FWD thing, as you might never be able to generate enough load on the transfer in FWD to prove it - the front wheels will just spin.

I would have though that if the chain was slipping you would feel a dramatic pause in forward momentum as it slips. I'm not all that familiar with the feel of chain slip though, so I can't be sure if that's normal.

Steve.

[christover1]

Can you feel it/anything through transfer or gear stick,
does either stick jump about when it happens?
Tranny and rear engine mounts didn't appear broken, but did appear soft.
A broken or worn front engine mount can appear quite well, without being so.
Engine didn't jump around much, but was hard to load it up.
Some lifts can cause rear shocks to hit axle tube, especially wider shocks.

I know nothing of inner workings of ARB diff locks, but could be wise to give them a hoy.

[Mike57]

Steve

After some more reading it does seem to be the chain. This case was always noisy since new. I am guessing that locking the rear and driving in sand has just been too much for it. I just need to work out now whether it is simply a matter of fitting a new chain or whether the slipping destroys the gear teeth. I will talk to the dealer tomorrow (out of warranty now anyway) but I think the only way forward now is to pull it out and take a look.

I see that the Jeeps also use a chain drive and have the same problem.

Mike

[Mike57]

Chris

Just saw your note. I agree the transfer mounts seem much softer than when they were new. I spent some time today going over all the mounts and looking for any other source of the noise but it is so loud that I think there is no doubt that it is the transfer chain. I don't have a transfer stick by the way just buttons. Who knows I may have a transfer stick before too long!

Mike

[christover1]

Sierra tranny with crawler gears
You know you want to

[Mike57]

With this experience I am definitely not going to a bigger tyre size. Who knows what will break next. A lot of mathematics and research to go through now to work out what a Sierra transfer will do to my ratios. Easy way out is to replace the chain. Need to sit on this for a while now. In the meantime I am grounded!

[Mike57]

I have ordered a transfer from a 2011 model from One Stop Suzi Shop on the Gold Coast. When I get the new one in I will pull the original apart and take a look. I always suspected my car had a problem with the transfer case and that was probably why it was sold at 4,000 km. Anyway I got the car cheap and so I am not complaining too much. $745 for the new (second hand) transfer case. Not sure when it will arrive. They are less responsive now they have my money.