Repetitive banging under load

Hi all, 2007 VVT manual Jimny with electronic transfer. I'm hoping you might be able to confirm my thoughts on an issue

When under load in 1st and 2nd there is a very load repetitive banging until I ease up on the accelerator. Its coming from directly underneath me and i'm thinking its the transfer case chain jumping. Its so violent that it makes the chassis ring.

It doesn't do it in any other gear except 1st and 2nd where more torque can be applied. Another symptom - if i'm driving in 2nd, let off the accelerator and then put my foot down, the banging appears until I ease up.

Its the momentary increase in torque that's causing it. Pulling away from junctions and hill starts is where is most evident.

Has anyone experienced this before, are these the symptoms of a slipping transfer case chain?

Many thanks for your help.

EDIT: Just thought i'd add - initially I thought it might have been something to do with the rear prop so I took this off, put it in 4WD and drove using the front two. The banging under load is still there, which is why I'm thinking it's the transfer case.

when did you last change/check the rear engine mount on the gearbox

Jack

I had similar noise last year. It was a broken transfer box mount. With the box hanging down a bit
the front prop was touching one of the chassis cross braces. Cheap fix though!

Thanks Jack, I haven't checked the mount actually, is it easy to get eyes on? Could a deteriorated engine mount cause such an abrupt noise and feel?

@1066Boy, this crossed my mind too. I checked the the transfer case mounts but they're fine and the front prop isn't coming in to contact with anything.

I got my hands around the transfer case and gave it a pull and a push, it felt secure.

MattB12 wrote: Thanks Jack, I haven't checked the mount actually, is it easy to get eyes on? Could a deteriorated engine mount cause such an abrupt noise and feel?

It's no so easy to see.But only takes 10mins to remove
my 1st failure gave the repetitive knocking and got louder round right turns under load
£25 from suzuki

Jack

Got it thanks, i'll try and have another look tomorrow.

If I could describe in words what it sounded like, bear with me It would be...BANG BANG BANG BANG BANG BANG...when under load, mainly pulling away.

yes it was bang bang also at some points it was more like rapid fire from machine gun gang bang


jack

That perfectly describes it Jack, machine gun rapid fire!

Thanks for your help, i'll report back.

Matt

Sounds exactly like the transfer box chain skipping to me.

Just an update.

I removed the rear engine mount today and it was intact. The only thing I noticed was that the rubber part of the mount felt a bit squishy, is this normal?

I was expecting the mount to be solid, or is it supposed to have a bit of play to it?

Many thanks

Matt

I'm going to see if I can get hold of another transfer box.

Question - will a 2013 transfer box fit my 2007?

Am I right in thinking all push button transfer boxes from any year will be fine?

Thanks