What would happen if some numpty fitted a classic WRX box to a UK car without changing the rear diff as well?

How obvious would the problem be?

Thanks

 

The front and rear wheels would turn at different speeds, and I would expect the handling to feel wrong. It would also end up damaging the centre diff'.

Can't say much more, because I've not experienced it. Try and get hold of Harvey, I know something similar happened to him.


Mark.

 

Thanks mate. That's what I thought. I need to make a phone call to the garage to find out exactly what they changed.

 

Does it feel like something is wrong??

 

it feels like you are driving over those lines they put accross the road on the approach to roundabouts. If you drive too fast for too long, the centre diff will ultimately lock up and then probably break something in the centre diff. In doing so an amount of the silicone gel will leach out the viscous clutch and turn the gear oil quite black.

If you drive slowly (no more than 40mph) then you should be able to avoid any serious damage to the diff, but it's no guarantee.

Paul

 

How do they do that then Mark ?

 

Not the easiest thing to spot I am afraid. It has happened to me TWICE and the first time the car was driven by Branko Bozic, Bob Rawle, Matt Clark, John (Porky) Pye and the nuget who did it in the first place, Pete Croney. Nobody was able to ID the problem but the car did not handle as well as expected despite a lot of time and effort over some months.
I then came down the motorway in the early hours of the morning and probably did the last 15 miles all above 150 mph. As I slowed for a roundabout off the motorway I could feel the transmission tight and stopped. I then had to apply a bit of power in first gear to move off and that only happened after a sudden bang. Obviously with the slipping centre viscuous things had got very hot and I was only able to move off when I broke something.
Over the next few days a vibration developed in the transmission and eventually when we could find nothing wrong with any of the UJs or driveshafts the box was removed. There was evidence of tremendous heat in the centre viscuous which was scrap. Pete Croney denied that running different ratios front and rear would cause any problem and he even told that to a judge who told him you did not need to be a rocket scientist to work out that it could not be good for the transmission or the handling of the vehicle. What an ar5ehole.
The front and rear wheels can only turn at the same speed and the slippage is taken up in the centre viscuous.
The second time it happened, I knew within a few hundred yards. We had changed ratios and I knew what mph per 1000 rpm I was expecting and I had the advantage of a very accurate SPA microprocessor. We were going from 4.44 to 4.11 diffs but the person responsible for the rear diff decided it was 4.11 because they were too lazy to count the crown wheel and pinion teeth. Also the car felt as if it was not freewheeling properly. Within 15 minutes I had the rear cover plate off the rear diff. I was upset and the air turned blue.
Now if I am doing anything like this or involved in any other transmission swaps I personally mark the gears or crown wheel with tipex and count them myself.

 

Wheelspin of course

 

When i had my uk turbo and blew the box i got an import one without the diff. Every time i accelerated hard the full car would vibrate

 

sorry to hijack the post a bit but going along the same lines what would happen if it was an auto box from a uk spec 2.5 put in to a jap spec 96/97 2.0l twin turbo? but kept the jap spec rear diff