Can I ditch the propshaft and go 2wd?

[phosty]

I have been experiencing intermittant vibrations or 'wobbles' of the tranmission/gearbox when accelerating from stationary. Anyway, took it to a garage and of course the symptoms went away - no joy.

Luckily (or not....) I had my Legnum in at Mitsubishi Aberdeen for leak on the rear diff and asked them to see if they could find anything that may be causing the 'wobble'. Well, they found it: the frnt universal joint on the propshaft is buggered. In their words - the car is unsafe to drive. If the joint fails totally I could end up with a propshaft through the passenger footwell so they said (not sure why the driver footwell isn't also at risk.

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Unfortunatley they only supply the entire propshaft as an assembly, and it will take 6 weeks minimum to order one. For a heck of a lot of cash + VAT + fitting.

I've already spoken to Mo/Zedy1 so hopefully he will be able to find a more reasonable alternative. However, in the meantime I was wondering if it was possible to just loose the propshaft altogether (temporarily).

I understand it would potentially double the forces on the front drive shafts - but I would drive very gently to compensate. So long as I don't give it some welly I should be OK? Aren't the VR4's 4wd setup so that they send 25% to each wheel? That still gives me 130 bhp without exceeding the rating for the front wheels.

What I am not sure about is can the rear diff freewheel (i.e. be dragged)without causing damage to it? Isn't this what happens when you coast downhill anyway? Or would I need to remove the rear diff crown wheel or the like too?

Otherwise I am going to have to start getting buses and riding my bike till the replacement arrives!

The joints themselves don't look serviceable - no circlips on the outside, just a star-type nut on the outside.

Or has anyone ever tried replacing the joints or having a custom propshaft (maybe carbon fibre?) made up?

[Kieran]

Have you tried these guys?

http://www.reco-prop.com/

[phosty]

I'll try them tomorrow. But that would still leave me without a propshaft temporarily. Can the 2wd thing work in the meantime?

[Nutter_John]

Wow thanks K they are near where I live and I have had an issue with my propshaft for months , inc quite a few heavy lauches at the pod and Trax

I will give them a call and see how much to fix mine

Phil , there was a VR4 in metro salvage in Bolton give me a call as I'm sure they have a prop shaft

[phosty]

Hmmn - would this fit? Can't see any universal joints though....

http://www.torqline.com/product_detail_38.php

[Kieran]

Hmmm..... There is a lot of EVO DNA in our cars..... But I would be surprised if Hiya Evilaki, Mitsubishi's top evil designer hadn't made it deliberately different somehow.

I guess a starting point would be the wheelbase of the two cars - Not exactly scientific as it depends on the legnth of the tailshaft from the transfer case, etc. etc, but it might be a good indicator to decide whether it's worth investigating in more depth...

John - RecoProp have been advertising in Practical Classics since they did that restoration of Noah's Ark... They've been around a fair old while, so I imagine they're trustworthy.

[Kenneth]

as an answer to your 4wd to 2wd question...

Yes and no :thinking:

You would need to weld up the centre diff in the transfer case otherwise you will just fry the centre diff. If you do this, then you can go 2wd.

Obviously this is a one way modification, so unless you have a spare transfer case or centre diff lying about then not a good idea if you want to go back to 4wd.

[Kenneth]

You could also ring up some engineering shops. While they may not recondition drive shafts themselves, they may know who in the area does.

My mate worked for a marine engineering outfit (well marine and general engineering) who did a lot of drive shafts, usually for boats and trucks but nevertheless they still did them.

Er, what I am trying to say is that it is worth inquiring about because often you can get things done well at a reasonable cost, just not where you would expect.

[Nutter_John]

Hmmn - would this fit? Can't see any universal joints though....

http://www.torqline.com/product_detail_38.php

The answer is no , I have a evo 6 prop shaft sat in my back garden ans it does not fit a vr4 , they are rought the same lenght but the mounts are in the wrong place and the center section can not be unbolted

[phosty]

OK - so after talking with a couple of garages they all recommend not driving the car due to the risk of the propshaft breaking free and dropping down onto the road and all that that would entail.

So I am really looking into taking it off as I don't have a replacement car to use in the meantime. So, as far as I can figure from the Japanese service manual (section 25) it's just a matter of unbolting the two centre bearings, diconnecting the back UJ where it bolts onto the rear diff, and pulling the splined shaft from the front transfer box.

Presumably this won't cause me to loose any fluids from either rear diff/ayc (fully sealed aren't they?) or the front transfer box? One garage thought I would loose fluids based on their experiences of Evo propshafts. Any thoughts?

Kenneth, when you say I would need to weld up the centre diff in the transfer case which one do you mean - the front transfer box/case that the propshaft splined shaft feeds into? Is that because it will leak it's fluids? If so then maybe that is what the plug item is for in the second service manual drawing (Item No MB991193)?

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[Kenneth]

Kenneth, when you say I would need to weld up the centre diff in the transfer case which one do you mean - the front transfer box/case that the propshaft splined shaft feeds into? Is that because it will leak it's fluids? If so then maybe that is what the plug item is for in the second service manual drawing (Item No MB991193)?

The diff in the front transfer case, which is attached to the gearbox and is shown in your last picture :)

No, it is not because of the fluid leaking, it is because the diff is a viscous LSD.

If it were a open diff, then you wouldn't be able to go anywhere, all the drive would go to the prop shaft side.

A viscous LSD uses fluid to create a resistance that resists one side of the diff going faster than the other. Because of this it will generate heat if one side is moving significantly faster than the other. With one side disconnected it is likely that the heat generation will fairly quickly destroy the oil and then the diff.
When you weld up the diff you make sure both sides of the diff go at the same speed regardless. This would cause issues if you were 4wd though.


Asside from that, apparently (I haven't tried it) the car doesn't really want to move with the prop shaft disconnected anyway. One suspects the LSD doesn't work well with significantly different loads.

[phosty]

Interesting, thanks guys.

Hopefully going to pickup a whole prop-shaft unit from Mo at the weekend which will be duly fitted.

John, since speaking with you I had a close look at mine and it doesn't look too healthy at the back end either, just as you decribed. Lots of play. So I don't think I'll be able to split the replacement - I'll likely need it all!

Going back to the transfer box, I see from CAPS that the part number is MD748268, 'Transfer Sub Assy W5A5,W5M5 (VCU)'. A viscous coupling unit just as you said.

Interestingly I searched google for the part number and came up with these two links here (http://www.coordsport.com/Transmission%20&%20Differential%20Information%20Nov%202001.pdf) and here (http://www.lancerregister.com/showthread.php?s=&threadid=164885&highlight=transfer+boxes).

these suggest we share the same part as the Evo 4-6 (The Evo 4 part no. is an exact match) and have open diffs with a VCU.

I still can't quite get my head around the specifics:

we have an open diff beteen the front wheels (is this inside the gearbox or a separate item?),
an open diff + VCU in the centre (as per link HERE (http://www.autozine.org/technical_school/traction/tech_traction_4wd_2.htm) ),
and an open diff + AYC between the rear wheels?

but anyway, it has put paid to my foolish idea of running without the propshaft in place.

Finally, presumably I need to be very careful when pulling the old splined shaft out of the transfer case to avoid scoring the oil seal that must be in there? Are these seals easy to replace if I do damage it? If I do get a leak I assume that wouldn't last to long either?

[orionn2o]

How much did the whole new replacement propshaft set you back?? If you dont mind me askin?

[phosty]

The quote from Mitsubishi Parts was £1790 + VAT + Fitting for a new propshaft assembly.

I have actually been in correspondance with Torqline (see post #5 above) about the prices for their carbon fibre replacments. The Evo propshafts that they sell as standard replace the rear two sections (it does away with the rear centre bearing altogether) and the one for the Evo 6-8 looks to have similar fittings on either end. Only problem is the length. I said I would measure it up and see how it compares but Nutter_John has already tried an Evo 6 propshaft and found it to be too short/long? so I guess it won't work.

So we won't be able to use the standard ones they sell (£1200 + VAT) but a custom one is possible. When I send them the measurements I'll see what they quote - but it won't be cheap! (It might compare well with a new Mitsubishi one though.....even if you do have to keep the old front section).

[l11king]

there is a place down here (glasgow) called euro drive shafts they recon them in a matter of a couple of hours. So i would think there is a similar place near aberdeen. the other thing you could do is replace the UJ all you need is a hammer a vice and a punch it is pretty straight forward to do If you took the prop off and took it into a bearing manufacturer they would make you one up. it is a we bit of hassel but a hell of alot cheaper It might be as little as £50 for the UJ and a garage would probably take a couple hours labour to change it.
hope this helps

[Nick Mann]

When you remove the prop shaft from the transfer box the gear oil from the transfer box will leak everywhere. The seal is a simple one and can be bought for about £10 from a stealership. As you said, care can mean that it won't need replacing.

The Evo 7 and the VR4 have almost (if not) identical wheel bases. But John says the mounting points are the issue, rather than the overall length?

[Nutter_John]

length does seem to be about right , maybe with more time and you could make it fit but don't think it's worth the effort

[phosty]

An update:

Thanks to Mo I was able to get a replacement propshaft (for a heck of a lot less cash than Mitsubishi wanted) and had a go at fitting it last weekend.

As was advised it turned out to be very simple really - the hardest part was jacking up the far high enough and so I could get access underneath. I ended up using two jacks on the passenger side front and back sill jack points and then popped a couple of axle stands (and a spare wheel) under the sill for security. Once that was done it was a relatively simple matter of unbolting the four bolts on the flange connecting the rear of the propshaft front section to the center section.

I had been warned that in order to get at all four bolts I would have to jack both rear wheels in the air in order to turn the propshaft to get at the top bolt. Which would have involved a fair amount of faffing around with the jacks/axle stands. As it turned out the top bolt was actually in the 2 O'clock position and I was then able to get a spanner over the nut and then using a double extension on the socket ratchet to reach from in front of the catalytic converter I was able to get the top bolt off (see pictures below).

Once all the bolts were out it was a simple matter of dropping it down and sliding it out of the transfer box just as John described. As I had also been warned about the transfer box oil dribbling out of the hole I already had a oil pan in place (110ml dribbled out for reference).

Fitting the replacement was simply the reverse of removal. I was worried slightly that the front polished internally splined part of the new front section might cause an oil leak because it had some surface rust. I polished it out as best I could with wire wool but there were still some imperfections. However, it hasn't shown any signs of leaking yet - fingers crossed. I tried to be as careful as I could when reinserting it into the transfer box to avoid damaging the seal - only to find that the bolt holes on the flange then didn't line up so had to do it again. Take note!

I tried as hard as I could at the weekend to find somewhere that would supply me with a large syringe so I could top up the transfer box oil that had dripped out. But I either got laughs of surprise from the vetinary suppliers when I described what I wanted to do with it or they thought I was some sort of weirdo. So at the moment I am 20% low on transfer box oil. I have finally managed to find somewhere that does actually sell oil change syringes since (see suction guns halfway down this page: http://www.performance-oils.co.uk/acatalog/Dispensers.html ) so that’s the job for this weekend.

You can see from the pictures below that the old UJ was quite literally gone! The cartridge bearing on one side was completely destroyed and the UJ cross out of it's socket. The bearing on the other side wasn't far behind. Because the UJ cross was off centre now the yokes of the UJ had actually been impacting on each other (see the bare metal scrapes) - this I know now was the reason for the knocking/vibration I felt when accelerating from standstill. Once up to speed I guess centrifugal forces centred the whole assembly automatically. The vibration when moving must have been due to the missing cartridge bearing causing an imbalance. Mitsubishi weren't kidding when they declared the car unsafe to drive. A close thing…..

I also got a quote from Reco-Prop for repairing the old front section - they estimated about £150 + VAT because they would have to completely replace the whole front splined/yoke section since there isn't enough room to cut off and replace the old UJ. The bearings Mitsubishi use are not replaceable. A complete second-hand propshaft from Mo cost about the same.

I also got more info from Torqline about a carbon fibre replacement (just in case I was unable to source a second-hand replacement). I'll post that info in a new thread to make it easier to find. But it seems the Evo 7-9 carbon fibre replacement for the rear two sections of the propshaft would fit out cars exactly. Wouldn't have helped me anyway since it was my front section that was gone. But good to know if you ever want to bling your propshaft!

Thanks for all the help guys!

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[The Vee]

Well done that man:thumbsup: Havn't seen a UJ like that for a while, that really was seriously worn!