Question on transfer boxes 80 series

[Chris]

Sort of a two in one this really. Firstly, I'm not the only one to suffer from some sort of transmission whine on my 80. Now, I really don't think it's the front diff as firstly it had only done 69k when I got it and secondly I swapped it anyway for a newly built JW diff. If anyone thinks that this is the cause of the whine, please direct comments to the good Diff Doctor, 'cos I don't.

When I lost the white truck and got the silver one, I swapped the whole transmission over and the noise that I'd had on the white truck came with it. At around 40 mph + you can play a tune on and off the throttle. I posted this recently on the 'waste of a morning' thread. I have pulled the rear output bearing and that seemed good. Whilst I couldn't get the front housing off completely I did disengage the splines so that I could spin the companion flange and that seemed good too.

So question one - does anyone know where the noise comes from. If we can rule out responses like 'is it a sized brake caliper?', I'd be eternally grateful. OK it could be actually in the auto box I guess but hard to tell. Knock it into N as you go along, it's going to go quiet whatever you're doing. I have not driven it with a prop removed to see if that makes a difference.

OK second shot. For some reason, the transfer box oil seems to stay clean for a very short period indeed. Yes, I off road, but not that much. The breathers are clean and have caps on. But the oil whilst clear going in seems very soon to turn muddy almost chocolate coloured. You'd expect 20k or more surely out of T box oil, but mine seems to only do a few K and there it is, brown again. Is there any chance at all that ATF could get out of the output seal and in through the opposite input seal into the T box? I don't buy that. On my 90 SWB I swapped it once and it was like Angel's tears every time I checked it.

Are these two things connected? Does anyone else have an on / off whine on their 80? It really spoils an otherwise very quite car.

I have a spare T box and when I come to do the TC front seal in the Spring, I might remove the T box to make it easier and shove the spare one on in its place when I reassemble.

So sensible thoughts chaps. It's quite vexing. Hard to tell where the noise is from as it gets conducted along the chassis etc. These things are always difficult I know. But someone may just have had this before and cracked it.

Chris

 

[adrianr]

Mine whines when you come off the power.

Replaced my front diff two and a bit years back. No difference so the whine is in that middle box somewhere but don't really no where. The ome lift made no difference to pitch or tone or volume. It is related to speed of components in the transfer case and is more noticeable in low ratio.

Flick it into n on the transfer box and it goes silent.

Oil stays crystal clear.

I have wondered that it is not bearing related but more to do with the components wearing on their contact surfaces and giving off a harmonic resonance depending on load?

 

[Dave Docwra]

If the oil is discolouring in the transfer box & the level is not rising, that would indicate something in there is causing friction to burn the oil, I would hazard a guess at the VC being the problem.

 

[Chris]

Noise is ON the power, goes quiet when on over run Adrian. And it's not really speed related, say like a wheel bearing. It starts to be noticeable at dual carriage way speed but really is a pretty constant tone after that rather than anything getting faster.

Hmm, interesting thought Dave. Got any more thinking behind that? I know we've had a recent VC debate on here which was extremely enlightening, but what would the mechanism be here for that to occur. I have said already that I have had some doubts about my VC. Easy enough to swap. Do you think that the VC could be the source of the noise too?

I could just take the whole housing off the spare and change it out without dismantling it to get to the VC. The spare T box does seem to have very good resistance when you try to turn the two drive flanges at different speeds. If you recall, I asked 'how much resistance should I feel at the wheel if I turn by hand' and in my case it felt a bit like an old LSD on a Prado. Is it a case of when they go, they jam solid or so they give up and lose drive between inner and outer?

We could be onto something here.

Chris

 

[Andrew Prince]

The VC should only get warm/hot when it's working properly If it's seized solid or the friction plates and oil aren't tightening up, then there's nothing related to the VC to generate heat. Of course a VC in the process of failing (seizing) may be binding more and more and generating heat. Another source of heat would be a bad bearing but you said yours was good?

But the oil whilst clear going in seems very soon to turn muddy almost chocolate coloured. You'd expect 20k or more surely out of T box oil, but mine seems to only do a few K and there it is, brown again.

I had this phenomenon too, and I'm pretty confident that the T/case and VC on mine is working 100%. The discolouration didn't strike me as being heat related - it looked more like a fine dust in suspension that discoloured the oil. Mine was more caramel-coloured but clearly different from new oil! When I took the rear housing off, the surfaces were all coated in this powdery suspension. Looked a bit like a pale graphite powder in the oil. In fairness I have no clue how long that oil had been in there nor have I drained the new oil I subsequently refilled it with so couldn't comment on whether my oil discoloration was possibly age/wear related. Only definitive way of determining what's going on with the oil is to get it tested - I'm sure an analysis would tell whether the oil was being cooked or if it was contamination and if so, whether it's another oil, wearing metal surfaces, dust, water etc.

In terms of noise, I thought you had digital radio? In all seriousness I think that one will require a process of elimination. Worst case scenario, it's two factors acting in concert (no pun intended). You've identified that it's drive related but only comes to the fore at a certain speed. This could indicate a resonance issue, hence my comment that it could be 2 factors. I think Adrian's suggestion about wearing gear faces is a good one but very difficult to prove!

Could be the prop(s) given that they will be spinning at different angles post-suspension lift than they were used to in their entire pre-lift lives. Thinking about it the list of possibilities is almost endless! Maybe shoot more without ear protection - it also has benefits when being given advice around the house

 

[Dave Docwra]

My thinking behind it is that the VC has a group of clutch/drive plates internally that could slip & cause overheating of the oil, I am thinking if you remove the rear prop shaft there could be very little or no drive to the front once heated up.Do take the rear prop if you take for a test drive..

 

[Dave Docwra]

Just checked transfer & gear box oil levels, they are both clean & no discolouration to speak of, thats after travelling through extreme heat & plenty of dust for over 12k miles.

 

[Chris]

Chaps, as always - sensible stuff for me to ponder on. Thing is of course that the noise is there in a perfectly straight line when none of the diffs are really doing anything. Nor the VC. But time to have a looking there maybe. I did renew the rear output seal a few weeks ago and the VC was all clean and nice. No signs of heat, leaks, rust - nothing. But it did look like the tide had gone out. Everything was coated in sort of orange desert dust. Just as described earlier - like solids in suspension in the oil. No idea where it might be getting in.

Yes - orange as in Lincomb dirt!!!!!!

Thanks

Chris

 

[Andrew Prince]

Have you tried it driving in a straight line with the CDL on up to the speed that the whine starts? CDL locked might rule out some of the potential issues around the VC as it would be guaranteed to inactive with the CD locked.

The particles sound similar to mine - I guess that rules out ATF leaks or similar soluble fluids. Likewise water ingress would make the oil milky, so can be ruled out. I did stick a new OEM bearing when I replaced the rear output seal on mine - when my LC has its glorious homecoming, I'll drain the oil and see what it looks like on the off-chance that the bearing has anything to do with it. Which I really doubt.

Cheers,

 

[Chris]

No, I haven't Andrew. To be clear, the whine doesn't really just 'start' it's just that it's noticeable at higher speed. It's there at 30 mph too, but gets drowned out with rising and falling revs etc. Only really when you get onto a smooth long road where speed is continuous (unlike a country windy road) that you realise that it's there. When you back off - it's heaven. You don't realise how loud it is until it stops.

Will try the CDL trick and see if it makes any difference. Although sitting here now, I rather think that I may have already done that. Sometimes these faults are only detectable under load conditions. You can pull a bearing and it seems OK. But you can't recreate the conditions of having a 3 t truck doing 70 mph through it.

I really would like to bottom this one though. One of the things that I was looking forward to when I lost the white one was having a new quiet replacement

Chris

 

[frank rabbets]

A bit off topic but mentioned in this post.........propshaft joints i.e. Hardy Spicer type. They are not constant velocity joints. If one side is connected to a flange spinning at a constant velocity and the other to a propshaft supported at an angle to the flange the propshaft speeds up and slows down during every revolution. This is cancelled out by the other joint on the other end of the propshaft, giving a constant velocity to the drven flange. BUT for it to work effectively both flanges must be in the same plane. I had dreadfull vibration in a car I rebuilt with 4 x trailing arms on a solid back axle. All 4 had the same part number and looked the same but in fact there were 2x short and 2 long and by some fluke I had the short ones on the bottom and long on top[could have been left and right!] Anyway after a week of crying I was lying under the car and noticed that the flanges were pointing in different planes. With baited breath I measured their lengths and eureka. [ Aston Martin DB4Gt with incorrectly made chassiss and one off trailing arms made and fitted by the factory as a correction under warranty].

Frank

 

[joinerman]

May be the same sort of thing your talking about Frank but i've heard mutterings before about prps have to be in" phase "

 

[L18 CGL]

Chris my silver truck is exactly the same after 60mph with power on it sounds like an old Leyland Lepard bus! Take the power off and it goes away. I was always unsure as to its source. I recently bought another truck for spares and robbed the gearbox out of it. I did aprox 300 miles in the spare truck before box came out and drive train was as quiet as a mouse. Took the whole gearbox inc transfer box out and put it in my silver truck and it still sounds just like it did before which leaves me looking at front or rear diff.

I have an AE86 corolla and have had diff over-hauled on numerous occasions for LSD plates and it was always noisy. The only thing that cured it was when I burst the crown wheel + pinion. I replaced then with brand new ones from Toyota and my diff/gearbox guy put a few new bearings in it and when it went back in it was whisper quiet.

 

[BobMurphy]

Propshaft joints i.e. Hardy Spicer type. They are not constant velocity joints. If one side is connected to a flange spinning at a constant velocity and the other to a propshaft supported at an angle to the flange the propshaft speeds up and slows down during every revolution.

A dumb question probably . . But does the '80' have a 'Hookes Joint' (double UJ) on the front of the rear propshaft in the same way as the '90' ???

That gives true Constant Velocity.

The front propshaft doesn't have one on the '90', but I think that's because the front suspension isn't designed to move as far as the rear, so less mis-alignment of the UJs.

Anyone who has driven a Series Land Rover in four wheel drive will know what happens when a UJ is running at an angle - the steering wheel snatches back and forth on a turn.

Bob.

 

[Chris]

Yes Bob it does. And the alignment is true. I adjusted the camber so that the front prop runs straight into the diff, It made the same noise on the white truck before I lifted that one too. So I don't think it's the prop in any way.

Chris

 

[frank rabbets]

The 80 does not have a double uj on the front but relies on the rear one to cancel it out. Movement up and down of the axle makes no difference as long as the flange face stays in the same plane, or there is very little movement,or there is low rpm like off road.

If you were to take off 1 uj, turn it round 90 degree and weld it back on you would have terrible vibration even with everything geometrically lined up. Joinerman, I think this must be the out of phase you must have heard about but it could not happen by accident.

When a pto propshaft broke on the farm once the end still spinning was quite happy to turn in midair and in fact the higher I revved it the truer it span. It only started going unstable when I decided to stop playing and slowed the engine then all hell broke loose. I thought "time to run again". I wonder if this would happen with a cvj or would the spinning shaft immediately turn at a right angle?

Anyway I was not linking all this to a whine just vibration and in my case a dreadful mechanical noise as the gears in the 'box and rear axle were rapidly going from on to off load.

My 80 has a high pitched gearbox whine over 50 mph. It's always had it.

Frank

 

[frank rabbets]

p.s. All my previous remarks have been from my experiences but now I have a computer I've just looked at "universal joints". All very interesting.

Frank

 

[Cptsideways]

Disconnect the front prop, engage CDL & see what it does. Sounds like a diff noise, especially if yours had been "rebuilt" it only needs to be a tiny bit out to make a BIG noise

 

[Chris]

Cheers Capt - but check the initial post. It did with my new truck on 69k diff, then put in a brand new JW built diff and it was exactly the the same. When it was in the original white truck it did it with the factory diff and still when I put the JW diff in. I'm guessing it's not going to be 3 completely different front diff that have all been checked.

@ Frank - sorry where are you looking? My 80 deff has a joint at BOTH ends of BOTH prop-shafts.

Honest - I counted them. 1, 2. 1, 2. Yep.


Chris

 

[Dave Docwra]

The only way the ujs could go out of line on the prop is if the slider has been apart & not realigned correctly when refitted, Chris Out of curiosity did you drive it before putting suspension lift in place, if not has the front shaft got some movement in the slider or could it be over greased, just thinking outside of the box, took me ages to think of that pun