[fiftywattplexi]

So after experiencing some hair-raising moments on a drive recently, I decided to check my VC. What was happening was, at random (but often) it would feel like someone grabbed the steering wheel and was trying to put me in the next lane. I would have to fight it pretty hard, then the truck would whip the other way and try to go the opposite way. I was getting a lot of vibration at freeway speeds and it felt like i was skating around on bald tires, except my tires all have good tread depth and I just got an alignment (which only helped slightly). Also I was experiencing the usual shuddering when turning in a tight circle etc so I figured the VC was at fault. Ok so I do the VC test with the xfer case in neutral and one front wheel in the air - its definitely completely locked up. I score another transfer case locally, seller ensures me its problem free - I stressed that the whole point I was getting it was for the VC and that I need to be sure its not seized. He says its perfect.

I get it home and decide to try and test it. Now, I'm not exactly sure how it needs to be done when its not installed, but I figured that if i use a pry bar to stop the output that drives the rear shaft and use another bar to turn the front output of the VC that it should be the same as when you have one front wheel in the air (please correct me if I am doing it wrong). Well, it feels like its completely seized as well, no 'resistance' at all, its turns 1 for 1 with the rear output and the input where it connects to the transmission. Will it make a difference if its in neutral somehow? I didn't think it would since its not installed in the vehicle. I think I bought a 2nd transfer case with the same **** problem I was trying to fix. :doh:
Rover gurus, please advise, I need this truck safe to drive as soon as possible! Many thanks in advance.

Fermin

 

[kmagnuss]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

I can't help you out with the VC, but the grabbing of the wheel part seems like something different than a VC to me. Have you checked your ball joints and tie rod ends for worn rubber boots and slop?

 

[fiftywattplexi]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

Have you checked your ball joints and tie rod ends for worn rubber boots and slop?

Yeah actually, I should have mentioned that it was the first thing I did. I ordered the complete track rod and drag link assemblies (Britpart brand) because at one point I was told by a guy at a wheel shop that one of the tie rod ends was shot. I got such a good deal (even with shipping across the pond) by buying them directly from a vendor in the UK that I just replaced both complete assemblies, all for less than what the one part would have cost me to to have ordered and installed locally. Kind of a shame too, because I would rather give local businesses my money.

 

[kmagnuss]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

Have you checked the temperature of your wheels after a drive? I wonder if a sticking wheel bearing or brake could cause the jerking? :think:

 

[fiftywattplexi]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

Good idea, hadn't thought to check that. I just know that a seized VC can cause the drivetrain to get wound up and make it behave like it has been, and mine is definitely shot :crybaby2:
Also, its not really a sudden jerking, its more like a hard pull, but hard enough that I have to countersteer significantly, once I am back centered in my lane the vehicle would continue to pull in the direction that I had just contersteered. This happens at low speeds as well, even just crawling along in stop and go town traffic - its much easier to manage than at freeway speeds but the strong deliberate wandering/veering is definitely still there. It doesn't really seem to favor one side or the other, its pretty random which side it wants to pull to.

 

[ferret]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

have you tried driving with no front driveshaft?

 

[ferret]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

from Ashcroft Transmission's page, I couldnt find it in my Rave

RRC, Workshop Manual, Section 41 Transfer Gearbox, Overhaul, Dismantle, Inspection & Overhaul.

You can either do this test on the bench or in the car with the handbrake on and one front wheel lifted.

Viscous unit - rolling resistance Bench check NOTE: Testing should be carried out in an ambient of 20 ?C.

Secure the output shaft ...

Apply a clockwise torque of 27 Nm to the (front propshaft) output flange nut. If no resistance to turn is felt, unit requires replacing.

If resistance to turn is felt, apply a clockwise torque of 20Nm to the (front propshaft) output flange nut for 1 minute, this should result in a rotation of approximately 25? - 30?. If no rotation or a greater force is required, unit requires replacing.

27 Nm = 20 lbf-ft 20 Nm = 15 lbf-ft

 

[fiftywattplexi]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

Well crap, just as I suspected. I dropped good money on a used transfer case that also had a shot VC. Anyone looking for a perfectly good transfer case with a seized VC?

 

[ferret]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

note, that was for an RRC not sure how different the numbers would be for a P38, doubt it is very different

 

[fiftywattplexi]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

The part number for the VC itself is the same for both the RRC and the P38.

Also, I need to amend my previous post: I went out to the garage and applied the steady pressure that the manual advised and I'll be damned if the thing didn't start to turn separately from the rear output! I think I was applying the pressure to 'fast' and the VC was just doing its job. The slow and steady pressure did the trick and I feel a ton better now that I know its OK. Probably doesn't help that its well below the recommended testing temperature so I'm sure its a bit more viscous the colder it is.

I still feel like an idiot, but at least this idiot has a working VC :dance:

******A million thanks to ferret for pointing me in the right direction!******

 

[Hoges]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

Have just replaced a seized VC... the give away is the "skipping" due to transmission windup when making a "gentle" u-turn on asphalt...and an inability to slowly turn one wheel raised off the ground... (yes, the handbrake was off :thumb: )

 

[Danny]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

I drove my Classic for ages (couple of years) with a seized VC. The only symptoms I had were scrubbing tyres in tight corners. Well, that and the exploding read diff. But as far as driving it went, it drove just the same as it does without a seized VC, so I'm also not convinced your symptoms are caused by that.

 

[fiftywattplexi]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

So a bit of an update, I have the replacement transfer case with the good VC in it. Some improvement, however it is pretty minor. I've noticed that the problem is happening still at both slow and freeway speeds, but it happens repeatably over certain sections of road every time. Sometimes its a pull to one side or a kinda slow side to side wander that I have to actively fight. I have realized that my shocks are toast, not really dampening at all anymore. It wasnt really that obvious at first because the OME HD springs are pretty firm. I'm wondering if the problem isnt just because of the shocks having failed and when ruts in pavement or a change in the crown/grain of the road causes the vehicle to want to pull/wander its caused by what I see as immediate body roll - also I am sure the steering damper is done as well. So 4 bad shocks and steering stabilizer - anyone else experience something similar?
Also, I checked the radius arm and sway bushings by pulling/pushing/prying with the wheels off the ground, I checked both at the frame and the axle - they are rock solid no tears or anything so I don't think they are causing any issues.
I have heard that the 255/55/18 setup was prone to wandering in the first place, any merit to this? The truck came with Kumho street tires from the previous owner, they are all in excellent shape with lots of tread and even wear.

 

[81stubee]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

It sounds like your having exactly the same problems as me!See my two threads here:

viewtopic.php?f=3&t=36300
viewtopic.php?f=3&t=34968

In summary, sometimes the car will seems fine especially on a flat new freeway. Othertimes it will wander horifically, bight on all road surfaces, throwing the car around. It feels like every wheel is trying to send the car in a different direction. I DO NOT ENJOY DRIVING MY P38!!!

Heres what I have done:
- New Tyres (GG AT2 255/55/R18)
- New Shocks (Bilstein)
- New Steering Damper (Bilstein)
- Removed front driveshaft again
- New Airbags (OEM)
- Several Alignments
- New Front Radius Arm and Chassis bushes (OEM) - Twice in 18months
- New Anti-Roll bar bushes
- New Height Sensors X4
- Calibration
- New Drag Link
- New Track Rod

I am currently having troubles with the EAS as it will randomly drop a corner, and I think this may not be helping. Just lately I had mY wife drive and have noticed a banging has developed on the left hand side again as if the bushes are gone. Its really doing my head in.

My plan is to fix the EAS and Viscous, replace the front driveshaft and then I will take it to a well known truck and 4X4 shop on the other side of town. They were the only people able to fix my disco after its lift, so i'm hoping they can do it again. It just seems that there is no-one around here is a real mechanic. They just plug there machines in and do what the book says.

Stu

 

[andyaa]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

Stubee - sorry to hear of all your troubles - I wondered who the person is you might take your Ranger to that you mention. It seems AMV haven't been able to help? There is a chap out my way (Inner West) I think his name is Pat - he works at a place called, I think, '4x4 wreckers' on the geelong road in Brooklyn - I think they do Jeep and Range Rover stuff - on the right hand side as you travel out of the city to geelong before you get to the Millers Road exit in Altona. He has a p38 and rovacom and is a bit of a guru - he did some work for me way back when and seems to know these beasts really well - I have his contact details at work - happy to hunt them out if you want them.

Regards

Andrew

 

[kmagnuss]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

Yes, the 18's are a little more suseptible to wandering (tramlining).

Since you know you need the shocks and steering dampener...I would replace those first and see what happens.

 

[viperover]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

Bearings, seizing brake callipers.....
c r a p tyres...

 

[KyleT]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

you are lifted, so your caster is off. that can cause alot of wandering and rut following. also, the steering box can get some play and needs to be adjusted out.

 

[fiftywattplexi]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

The odd part is I noticed the wandering ever increasing even while I still had airsprings installed. It would wander and especially pull badly at any height, with only minor improvement at lower height settings than at taller ones. It didn't start off this way, just used to kinda pull to one side only like it needed an alignment, sometimes the steering would shudder when getting up to freeway speeds. After I replaced the track rod and drag link and had it aligned the shuddering was significantly reduced, but not 100%. I tried giving it just a touch of toe-in by lengthening the track rod 1/8" to get it to wander less, as I had read on several other posts to try and compensate for the camber issues that are caused by my mild lift...it helped significantly at low speeds with the random strong pulling to one side or the other but still didn't cure it. Freeway wandering and pulling has been improved but only by a small amount. However the shuddering is now back when going over maybe 40mph. I'm getting my shocks and steering damper today, also most likely going to just go ahead and replace the radius arm bushings even though the look OK since the vehicle has taken quite a beating by the previous owner and also by me during a few very long very very bumpy rides during EAS faults (its a long way from sea-tac airport to everett, wa on bumpstops!).

I'll post an update when I'm done installing those parts today.

 

[Hoges]

Re: How Do You Test For Seized Viscous Coupling Off Of Vehicle

Lesson 1: Front wheels... no toe in or toe out...set them straight ahead...
Lesson 2: The steering damper is there to minimise violent shifts of the wheel due to the front wheels being diverted suddenly...e.g. going over rocks, stuck in sand / rough country / deep water on one side etc ...without a steering damper in those situations there's a possibility of breaking one's thumbs, or wrist even in a bad case (which is why instructors in trucks used insist that one drove with the thumbs on the front edge of the steering wheel, not wrapped around it... thus the wheel could "spin" through your hands without causing injury)
Damping the steering for normal road use will in all likelihood mask other problems. You should be able to drive around normally (suburban/freeway etc) and not need a damper...

hope this helps
cheers