I'm hoping it's an easy problem to diagnose or someone else might have already experienced this..

My front differential (I ASSUME) is slipping only when in reverse gear. I can go full throttle and spin all 4 tyres in forward, but I start getting a loud banging noise everytime I engage reverse to get out of a slippery situation.

I had accidentally drove on dry pavement in 4L with the front hubs engaged, was using the low range to climb some steep hills.. I honestly though I had them disconnected..  It's only after that incident I started noticing the slip..

- My air actuator seems to be working fine, it holds pressure, the rubber lines are ok and I have full 4WD in forward.

- I have Superwinch manual hubs, I had opened them up this evening and the gears inside seemed fine.

Did I damage my front differential? Any suggestions on what might have worn out in them?

Sounds like the pneumatic clutch in the front diff is slipping - it may be damaged.

If you want to use 2WDLo, you are better off using a switch in the line from the TC to hold that clutch open.  If you use an illuminated switch, as I did, you know where you are:

http://bbs.zuwharrie.com/content/topic,38056.0.html

^ That's something I want to install and should be pretty easy considering i'm already familier with the 4WD module wiring / location etc..

Is the pneumatic clutch replaceable? I currently have the 5.125 ratio gearing in my front diff and finding a used replacement in my country with that same ratio is very difficult. Chances are I will end up finding alot of 4.8 ratio diffs.. I guss it's either I swap the clutch or swap the ring and pinions..

I believe the clutch is the same on the auto and 5 speed, but there are differences based on the year, the later ones are supposedly an improved design.

Maybe it's time to get rid of the pneumatic clutch.

I believe the clutch is the same on the auto and 5 speed, but there are differences based on the year, the later ones are supposedly an improved design.

Maybe it's time to get rid of the pneumatic clutch.

Are you referring to using something like zip ties to permanently keep the clutch engaged?

The ziptie fix is more for a leaking actuator or maybe a failed pump/controller - my suspicion is the dog teeth on yours are badly damaged, and zip ties might not work - so either weld it - or - there's this

I'm puzzled - thinking a little more about this - whilst driving on dry pavement in 4WD is not recommended, it can be done provided you going in straight ahead with no damage - I do it about once a month, if I haven't used the 4WD, to lubricate the front crownwheel & pinion.

If wind up occurs you will get that characteristic "bang" from the pneumatic clutch, sort of as an early warning, and I would think, that if you were going to damage the teeth, it would be on the leading edge which should cause a problem going forward rather than in reverse.

I can't imagine that you would not have recognised the bang and it's implications - the few times I've heard it, it sounded like something broke and it was going to be a very expensive repair.

Actually, I got no bang from the clutch while I was in 4WD, only a creaking sound coming from the front of the vehicle. At the time, I thought the creaking sound was coming from the suspension as it was very rough pavement I was driving on.. Now I believe it came from either the front diff or the hubs..

I have the original factory hubs for my van still, so I will replace the Superwinch hubs with those to ensure they are not at fault. Once i'm sure the hubs are good, I know the fault will lie somewhere inside the front diff..

Are you sure it's not the t-case. My k5 did almost the same thing but it was the chain in the case, I was "stress testing" it before the first run by holding the brake and giving some gas , I'm still glade it happened in the drive way instead of the bush, after that it would handel light loads in D but the chain would slip and pop in R with any amount of throttle, at first I thought it was the diff or the splines on the drive shaft

are our t-cases chain drive though, I think but I'm not sure

^ Not sure about that one.. but I can look into it..

From the outside, the sound is definitely coming from the front of the vehicle.. so i strongly suspect it's the diff.. I just can't picture why it would only slip in reverse..

are our t-cases chain drive though, I think but I'm not sure

Yes, they are.

I intentionally got my GV stuck today to take a closer look at what was going on while the slip was occurring.. I had a assistant spin the wheels in 4WD reverse while I looked on from outside. I noticed that each time the slip / bang occurs, the front diff would shake violently.. I then placed my hand on the bottom of the transfer case and when the slip occurred, I didn't feel any unusual vibration..

I'm taking that evidence to mean that the fault likes inside the front diff..

Next week when i'm off work, i'll take down the diff and have a closer look inside..

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If the fault is in the clutch, will it be ok in the long term to permanently lock it in place (using something like zip ties or a stronger material) and drive around in 4WD with my front manual hubs locked? I figure with the clutch permanently locked, the front diff would keep spinning while you drive and the only way to stop that is to unlock the manual hubs..

The ziptie fix is more for a leaking actuator or maybe a failed pump/controller - my suspicion is the dog teeth on yours are badly damaged, and zip ties might not work - so either weld it - or - there's this

like i missed this post..

what's the dog teeth about? part of the clutch system?

I didn't think it would be this difficult to find a picture or diagram of a dog clutch on the internet - think of a gear, but instead of teeth on the circumference, they are on the flat end face, now take two of those and position them so the teeth on one, fit in between the teeth of the other - slide them together, one drives the other, slide them apart, there's no drive.

Anyway, here's the front differential assembly from the Grand Vitara, this image is in section 7E of the FSM if you need a clearer picture ...



#25 is the free wheel hub - this fits inside the differential case (#17) and has the differential pinions (#26) attached to it, the side gears (#24) are attached to the axles, and this entire assembly rotates with the wheels.  There are teeth on the end of the free wheel hub, and matching teeth on the axle lock clutch, which is on the end of the left differential case (#27) - when in 4WD, the actuator pushes the axle lock clutch teeth into mesh with those on the free wheel hub locking the differential case and the free wheel hub together so they rotate as one (when in 2WD, the two can rotate independently).

Whilst it is theoretically possible that the actuator is not pushing the clutch sufficiently into mesh, and this is what's causing the slip - I would expect this to affect both forward & reverse, so the fact that it works going forward but slips in reverse is what leads me to believe, the teeth may be worn.

Just so you're aware of it - to get to the clutch, you need to disassemble the third member, and reassembly will require the adjustment of backlash (in theory you can mark the adjusters and then count the turns as you unscrew them), don't undo the pinion nut or you'll need a new crush sleeve and will also need to adjust the pinion preload - this is a job that requires some level of experience.

^Thanks for that informative reply, work is keeping me busy these days but I am still to begin work on examining the differential. I have the assistance of a transmission mechanic to assist in the difficult assembly work.

Let me know if I have this correct.

There are teeth on the side of the free wheel hub #25. The teeth are not shown in the diagram.

The air actuator pushes the free wheel hub into #27, which is part of the differential case, and that is when the power is transmitted to the front wheels.

So to permanently lock the hub, I will have to get #25 welded to #27..

I feel I have it wrong somewhere.. but I figure I will get a better understanding of what's going on in there when I open it up..