[headwerkn]

Hi all,

Was hooking some firewood on the weekend, needing 4WD for the first time in a few weeks and noticed that the transfer case on my '93 LWB won't go into 4H from 2H while moving. Basically it just makes a horrible grinding noise while refusing to synch gears. Come to a rest and it goes in fine though.

Normally 2H->4H can be done at up to 80kmh without issue - I do this all the time as I travel on gravel roads a fair bit and the Vit is much more stable at speed in 4WD. As with most part time 4WD systems it is only 4H-4L and vice versa that requires the vehicle to be at rest.

OK - so what happened in those few weeks prior? Well, about a month ago some muppet managed to crash into my driver's side rear wheel. Literally. Other than taking out my driver's side mirror and a small dent in the wheel arch, the wheel/axle took the entire brunt of the accident... me doing 60kmh and him 80kmh into me. No wonder the rear axle bent several degrees. Anyway, the entire rear axle was replaced and the car is back to good, save this minor issue.

I can't see how replacing the rear axle would mess up the synchros, etc. in the transfer box? The car did get a jolly good jolt in the accident - the front bar needed to be restraightened - so I'm wondering if the impact might have knocked something out of place.

Any ideas?

Cheers, Ben.

[Scrawny]

Did you swap in just the diff housing or a complete diff head etc? Sounds like the diff ratio may be different?

I'm assuming both the FWH's are still locked in?

[headwerkn]

Just the diff housing - the original rear diff was undamaged and thus refitted... no point wasting extra money on the repair.

Hubs were locked in prior.... though I gave 2H->4H another go at roughly 40kmh this morning with them set to FREE and got the exact same issue.

Having to come to a rest to engage 4WD isn't the end of the world, but I am worried it being a symptom for some kind of damage to the transfer box.

[Scrawny]

Are the hubs actually locking in? Are all 4 tyres the same size? It should just shift between 4H and 2H without dramas while moving

[headwerkn]

I'm pretty sure the hubs are locking in A-OK - had no probs with traction while off road.

All four tyres are the same size (215/70/R15) however the new one is a different brand and looks oh-so slightly narrower. Rolling diameter should be the same give or take a few millimeters.

Will call up my mechanic mate who actually did the swap over, see if he can think of anything...

[Reubs]

headwerkn wrote:

All four tyres are the same size (215/70/R15) however the new one is a different brand and looks oh-so slightly narrower. Rolling diameter should be the same give or take a few millimeters.
...

It is poor practice and I thought it is illegal to have differing tread patterns on the same axle. If the tyres look visibly different than that is likely to be your problem.

headwerkn wrote:

I'm pretty sure the hubs are locking in A-OK - had no probs with traction while off road.

You would need to jack the front wheels up whilst in 4x4 with hubs locked to check if they free wheel or are locked. As an example it is also possible to drive a suzuki up the beach in 2wd and never have a problem with traction.

[headwerkn]

Reubs wrote:

headwerkn wrote:

All four tyres are the same size (215/70/R15) however the new one is a different brand and looks oh-so slightly narrower. Rolling diameter should be the same give or take a few millimeters.
...

It is poor practice and I thought it is illegal to have differing tread patterns on the same axle. If the tyres look visibly different than that is likely to be your problem.

I can't say I'm thrilled by it either; unfortunately Bob Jane advised that the Maxxis MAP1s I have on the other corners are now discontinued/unavailable... the alternate Nexxus is pretty similar but does have a slightly different tread pattern/style. I would hope that Bob Jane would've advised if having a single different rear wheel was illegal - they certainly don't fail to upsell you other stuff whenever possible!

There's another original Maxxis on the spare, however it is on a 15x8 rather than 15x7 rim, and has a few light sidewall cuts from touching the inner guard when flexing. Not sure why the previous owner put 15x8s on the rear (stuck out a mile). I was keen to keep that just as a spare but I suppose an option is to get somewhere to swap the tyres/rims around and see if that clears up the issue. The truck will get good A/Ts next year once the body lift is done, really I just needed to get past Xmas without spending a fortune.

Reubs wrote:

headwerkn wrote:

I'm pretty sure the hubs are locking in A-OK - had no probs with traction while off road.

You would need to jack the front wheels up whilst in 4x4 with hubs locked to check if they free wheel or are locked. As an example it is also possible to drive a suzuki up the beach in 2wd and never have a problem with traction.

[/quote]

Will check tonight. Certainly there was no grinding, knocking or other suspicious noises going on while in 4WD for nearly 2 hours.

[headwerkn]

Just an update - things seem to have come right.

Going 2H->4H at standstill then swapping in and out on the fly thereafter seems to have resynchronised whatever was out of sync.

Just got back from our Xmas-NYE camp with 300km+ of alternating sealed-gravel roads, never missed a beat switch in and out of 4H at speeds up to 70kmh.

Weird issue indeed...

[fordem]

Just so you're aware of it - there's no synchro mechanism in the SE416 transfer case.