No 4wd..

[BobMurphy]

If Bob wants to suggest a series of diagnostics (front left wheel in the air, locker in sort of thing) then I can go through them. I've had 90s in bits so I know what I am looking for. Chris

Good man Chris - We'll get Ben sorted one way or another .

I'll write out some tests as you suggest.

My suspicion is that its the Transfer Box, so I suggest that the first thing to do is eliminate the axles as the cause.

You know all about drive shafts and diffs, so I won't have to go into nitty-gritty detail.

If it is the Transfer Box then if someone can remove it and send it to me I'll attempt to sort it.


I'll be back .


Bob.

 

[chadr]

A big thumbs up to Chris

You won't get a much better offer than that Ben. I'd be there is a shot, even if I was much further away!

 

[TonyP]

Two very good offers from folk who know their beans... That's what makes this place awesome!

 

[clivehorridge]

Bravo Chris & Bob.

The ball is in Ben's hands and IMHO he couldn't do better. In my experience, more than half of a mechanic's bill can be consumed by identifying the problem. The fix will have a cost for sure, but a free diagnosis and prognosis from trusted experts is a very valuable and generous offer.

I'm proud of you guys!

 

[Doodle]

It would have been

Ben's balls in their hands

...if he'd gone to a dealer.

 

[clivehorridge]

Ha, ha, ha like that Doodle !!

 

[BobMurphy]

Right, I'm back.

Having had a bit of a think I've written out some tests. The first one could be done by Ben and A.N.Other before going to Chris' place.

Here we go:

From what has been written, there is one simple test to identify where the problem lies.

With two people:

Put the transfer box into ‘H’ (centre diff open) and the car into first gear. Now try to drive forward.

There will be no movement and a nasty noise from somewhere.

The second person then has a look under the truck with a torch (BE CAREFUL - don't crawl underneath with it running!).

If the front propshaft is spinning the problem is at the front.

If the rear propshaft is spinning the problem is at the back.

If neither propshaft is moving the problem is in the Transfer Box.

Simples!


If the problem is in the Transfer Box I’m afraid it has to come out to be repaired. It’s likely to need a Centre Differential repair.


If the problem is in an axle we need to determine whether it’s a driveshaft or a differential problem (it could also be stripped splines on a Companion Flange, but I think that’s unlikely).

Front:

Engine off, Gearbox in Neutral and Transfer Box in ‘HL’.

Jack both front wheels off the ground (rear wheels on the ground, handbrake on).

Turn one wheel – the other one should turn in the opposite direction and the front propshaft shouldn’t move. If this happens and it feels ‘normal’ it indicates that the Crownwheel & Pinion have a problem and that the diff pinions are OK(ish). Both driveshafts are working.

If the ‘other’ wheel doesn’t move it indicates that a driveshaft is broken – but which one??

Put the Transfer Box into ‘H’.

Hold one wheel and turn the opposite one – does the propshaft turn??

If No – you are turning the wheel with the broken driveshaft.

If Yes – try holding/turning the opposite wheels.

This should reveal which side the driveshaft is broken.

BUT . . . There is a world of difference between turning something by hand, where broken bits can catch and appear normal, and doing the same thing with 100BHP behind it. Be aware that the truck can fool you so check very carefully and pay attention to ‘feel’.

Chris knows all about replacing driveshafts (I haven’t done that) so I’ll leave it at that.

If it looks as though the Crownwheel & Pinion have stripped the diff will have to come out, which means drawing the driveshafts out and so-on.


Rear:

Just repeat the above tests with the rear wheels off the ground and the front wheels grounded – Handbrake off.


If it looks as though an axle diff has failed, drain the oil and see what comes out – That should prove that you didn’t imagine it!


I’m sure that there are other tests that people will suggest and much will depend on what you find on the day. This should be a reasonable starting point though.

I’ll look forward to hearing the result.

Bob.

 

[benedmonds]

Right, I'm back.

I’ll look forward to hearing the result.

Bob.

Much appreciate the advice, when I get time I will check and get back to you. Thanks ....

 

[clivehorridge]

Bob,

A very comprehensive and sensible top-down approach to the unknown. I'm impressed. Before your post I was thinking how I would go about diagnosing which shaft was broken, which diff was working and so forth.

You made it all sound so easy and methodical.

Bravo!


Sent from my iPad using Tapatalk HD

 

[Graham]

Wow, thats a great diagnosis,

It all sounds so easy when it is well explained.

Good on you Bob.

Gra.

 

[OG.]

Good post Bob, but as its a 90 it has independant front suspension so exposed front driveshafts. In this case a broken driveshaft will be very obvious (and noisy as it bangs about). A broken CV (or stripped drive flange) will give a similar symptom to a failed driveshaft and will be obvious by having an assistant turn a wheel (whilst jacked up) and holding the driveshaft between hub and diff.

 

[Shayne]

Sorry to persist with this coz i realize i'm not making myself very popular with my guesses but as a novice myself on the subject at hand i can sympathize with benedmonds who very probably like me does not speak the lingo of those on here who are far more qualified than myself to give good advice .


As a novice the very first thing i would do is drain the transfer box looking for signs signs of metal chips in the oil . If i didn't find any metal i'd put new oil in and try to engage hh a few times again .

 

[Chris]

That's alright Shayne everyone's a novice at some point and as long as you pick stuff up along the way, that's all good. Obviously we shoot anyone who asks the same questions twice

Nothing wrong with the oil debris analysis idea there. It's just that it costs. Oil isn't that cheap and whilst having chips in there is helpful, NOT having chips isn't. Other than to say there aren't any chips. It sort of only works one way as a diagnosis. All of the tests that we are suggesting are free and dead quick. Probably quicker than changing the oil to be fair. And once done should define the exact nature of the problem. Chips in the oils will only show that there IS a problem, not what that problem actually IS.

Make sense?

Chris

 

[Shayne]

It does Chris , my concern is more ben might be frightened off by comments well suited to an engineers journal , it reads like doctors speak to those without the vocabulary and like everyone else i'd like to see him get this sorted .

Do you not think a transfer oil change and an aggressive yank on the might possibly free up something that sounds unlikely to have been used since he bought the truck ?

 

[Chris]

Well Shayne, you can never rule it out, but given the grinding noise it's making I rather fear that some of the contents of the box have been re-arranged. Yes the list may look a little daunting, but it wasn't for Ben, it was for me. Seeing as I am the one who offered to have a look at it for him free of charge at my place based on the fact that he's only a few miles away.

Chris

 

[BobMurphy]

As a novice the very first thing i would do is drain the transfer box looking for signs signs of metal chips in the oil . If i didn't find any metal i'd put new oil in and try to engage hh a few times again .

Sorry Shane but there are a couple of reasons why that might not work.

1. The Centre Differential is a closed drum with shafts coming out of front and back. The most likely cause of the problem is a failed Planet Carrier (sorry- Geek-Speak) in which case the bits won't get out into the oil but will be like gravel in a cement mixer.

2. There is an oil pump in the Transfer Box which has a fine strainer that can trap things. It also has a largish magnet in a housing next to the strainer that catches ferrous swarf in the oil.

This is why there isn't a magnet on the drain plug.

The only things to come out with the oil will be jointing compound and alloy - and that would be REALLY bad news.

I can post pictures of what goes on inside a Transfer Box if anyone is interested (and hasn't been to the "the other side" ).

Bob.

 

[Shayne]

I can post pictures of what goes on inside a Transfer Box if anyone is interested (and hasn't been to the "the other side" ).

Bob.[/QUOTE]

in truth i just can't get it out of my head the assumption (my assumption) that you pull a lever and it slots one cog into another , i searched for an alternative name rather than repeating "the linkages under the lever" and discovering it was seperate from the gear box i just thought , why not drain it and see .

 

[Chris Green90]

I can post pictures of what goes on inside a Transfer Box if anyone is interested (and hasn't been to the "the other side" ).
Bob.

I loved that thread on the other side Bob. It really taught me alot, In fact most of your threads do. I have been collating them over the last 6 months or so into a sort of "Haynes" type thing for me to be able to quickly refer to them with ease.

 

[BobMurphy]

For those that don't know what we're talking about - have a look here:

http://www.tlocuk.co.uk/forums/view...rder=asc&highlight=transfer+box+works&start=0


And here:


http://www.tlocuk.co.uk/forums/viewtopic.php?t=7848&highlight=stripping+transfer+box


Not a quick read though .


Bob.

 

[clivehorridge]

Wow Bob, truly amazingly and simply explained, even I understood at least half of it! I'm going to read it again and again to familiarize myself with the components (not having had one apart yet) and really understand what's going on in there.

Thank you, thank you, for your time and effort sharing this with us mechanical infidels.