Ix fails jack test what next

[fnf01]

I’ve done some searching but honestly I need a ix for dummy’s translation at this point. I bought an 5spd ix with the hope to save it from the crusher. It’s got some deadly rust issues but I figure it’s cost of tutition to learn to weld which is something I’ve always wanted to learn and now I have an excuse. It runs and drives, I’ve stopped using it as I need to do the timing belt but when I was putting it on jack stands I tried to do the jack test it failed. I lifted one front tire and tried to spin, spins easily one finger. I got it all the way up on stands and in gear only the rears move. Anything I can do to save the awd? A new VC? I see mention of both rebuilding and not able to rebuild VC? Is the ix viscous lsd in the for sale section what I need. Any idea what I’d be looking at to get it fixed? When I fix the rust I’d like to keep the car it’s a nice color combo lol, the year is kinda sentimental, and I’d be kinda sentimental about fixing it lol. I’ve read I can keep driving it with the bad VC with out causing more damage and plan too until I could source a fix. I really want the VC as this is intended to be a winter car.

[Kershaw]

What next? Ignore it, that's what's next.

When everything else is taken care of, then replace the transfercase. Until then, it's still awd, just an open diff. It's not like you can't drive around or will hurt something more by leaving it. Take care of the timing belt and then the rust. By then, you'll know what you want to do with the car more clearly anyway.

[nando]

yeah, I'd wait until you find a deal or get lucky with a good used TC. It's fine to drive as is.

Boy am I glad I bought that brand new in box TC a few years ago.. it was only $900. I don't think you can even buy them now. :(

[Julien]

What next? Ignore it, that's what's next.

When everything else is taken care of, then replace the transfercase. Until then, it's still awd, just an open diff. It's not like you can't drive around or will hurt something more by leaving it. Take care of the timing belt and then the rust. By then, you'll know what you want to do with the car more clearly anyway.

I don't think that's completely accurate. If you pull the ebrake and put the rear wheels on dollies the front wheels won't pull the car forward. Since the viscous coupling is shot the transfer case is actually slipping. The car is really just rwd.

edit: nope i'm wrong

[nando]

incorrect. You're describing the behavior of an open differential, which is what Kershaw said. It's *always* AWD, it's physically impossible to make it RWD (unless you remove a driveshaft).

It's easy to confuse what the VC does - it doesn't really transfer any torque at all. It only limits the rotational speed between the front and rear axles. The torque transfer is done 100% by the planetary gear set, which is always fixed at the same ratio (~33/67).

The transfercase is similar to a limited slip differential between the front and rear wheels. The fried VC makes it act like an open diff.

On an open differential, the end with the least grip gets all the torque. That's exactly what happens with a fried VC (the slipping end just spins, the gripping end doesn't move). Typically that will always be the rear, because it always gets double the torque of the front.

If you locked the rear wheels somehow, the front wheels would be forced to turn. This is actually how BMW does 'electronic' LSD on modern BMWs - they brake the 'slipping' wheel, forcing torque to the wheel with more grip.

Of course the torque from the engine would easily overpower the ebrake pads in reality (and it's a shitty system compared to mechanical LSDs).

[fnf01]

Thanks for the advice, I'm out of state for work until next week, waiting on metal, and waiting on timing belt + goodies. I'll start probably next weekend and go from there. If someone comes across a good transfer case please pass it along!

[Julien]

incorrect. You're describing the behavior of an open differential, which is what Kershaw said. It's *always* AWD, it's physically impossible to make it RWD (unless you remove a driveshaft).

It's easy to confuse what the VC does - it doesn't really transfer any torque at all. It only limits the rotational speed between the front and rear axles. The torque transfer is done 100% by the planetary gear set, which is always fixed at the same ratio (~33/67).

The transfercase is similar to a limited slip differential between the front and rear wheels. The fried VC makes it act like an open diff.

On an open differential, the end with the least grip gets all the torque. That's exactly what happens with a fried VC (the slipping end just spins, the gripping end doesn't move). Typically that will always be the rear, because it always gets double the torque of the front.

If you locked the rear wheels somehow, the front wheels would be forced to turn. This is actually how BMW does 'electronic' LSD on modern BMWs - they brake the 'slipping' wheel, forcing torque to the wheel with more grip.

Of course the torque from the engine would easily overpower the ebrake pads in reality (and it's a shitty system compared to mechanical LSDs).

For some reason I had pictured it as a viscous rear differential where there are no planetary gears and the viscous bit allows for the delta in f/r wheel speed. Looking at the exploded diagram I can see the gears now. My bad. Themoreyouknow.gif

[The Dark Side of Will]

It's easy to confuse what the VC does - it doesn't really transfer any torque at all. It only limits the rotational speed between the front and rear axles. The torque transfer is done 100% by the planetary gear set, which is always fixed at the same ratio (~33/67).

Let's go down this road again!

The VC *DOES* transfer torque, but it does it in proportion to the front-to-rear speed difference.

Say you put 300 ftlbs into the T-case, but your front tires are on ice and have zero traction (or, say, the front driveshaft is removed). The planetary gearset wants to send 100 ftlbs forward and 200 rearward. The front driveshaft will start to spin while the rear will not. The speed difference will cause the VC to start to send the front torque to the rear driveshaft. The planetary gearset wants to send 100 ftlbs forward, and if the speed difference gets high enough, the VC can transfer all 100 fltbs back to the rear axle. This is why the car still moves with relatively little impact when the front driveshaft has been completely removed.

What takes a little thinking to grasp is that the VC acts on the speed difference between the front and rear outputs. That means that if you have enough traction to put the torque down with no tire slip, you can put 1000+ ftlbs into the T-Case, the planetary gearset will distribute it, but the VC does absolutely nothing because both front and rear outputs are turning the same speed.

[nando]

Right, what I mean is - torque still gets to the wheels regardless of the VC.

Contrast this with certain VW vans that also used a VC - all of the torque physically transfered through the VC. If the VC died, the car couldn't move at all.

[The Dark Side of Will]

Mercedes 4matic systems and the Porsche 993 & 996 AWD systems operate the same way; The VC transfers ALL the torque going to the front driveshaft.

[nando]

For some reason I had pictured it as a viscous rear differential where there are no planetary gears and the viscous bit allows for the delta in f/r wheel speed. Looking at the exploded diagram I can see the gears now. My bad. Themoreyouknow.gif

The rear diff is similar. It doesn't have a planetary gear, but the spider gears basically split the torque 50/50. So with a bad rear VC, both wheels still get torque - until one of them loses traction, just like an open rear diff. :)