Ford Escort RS2000... 4x4 mk5

Not sure how it all works but I do no there a mint car.my brother had1 and it was really good.handled mint and went well too

The 4wd system can only really be described on these at best as err pants really !!!!!!
Rare car though now I imagine

There was a turbo one in PF mag a couple of years back still running the standard transmission, was knocking on the door of 300bhp IIRC. Good cars but transmission losses in standard form are horrific.

The 4x4 version of the MTX75 gearbox was restricted by the cost and packaging requirements that were placed on the original design - it had to fit in the existing FWD CE14 (Escort Mk5) floorpan with as little change as possible and reuse as much of the existing FWD MTX75 gearbox design as possible:

To provide the rear drive, the front differential was replaced with a hollow housing attached to the final drive gear which terminates in a hollow shaft that feeds into a planetary-geared centre differential in the transfer box. The centre differential splits the torgue from the final drive, 40% going into the front diff output shaft (which is also hollow, and runs inside the final drive input shaft back into the front diff inside the final drive housing) and 60% to a geartrain, which converts the rear drive output to the correct ratio (to match the the front and rear axle speeds) and then rotates it 90 degrees via a pair of bevel gears to the output for the propshaft.

The front diff ia a conventional geared type unit which is also viscously-coupled to the final drive housing to cope with any traction-induced speed differences between the front and rear axles. The RH front diff output then runs inside the hollow front diff input shaft (which is itself running inside the hollow final drive output shaft!) through the transfer case to connect to the RH front outer driveshaft.

The rear diff is also a conventional geared type (a 6.5 inch Sierra unit), which together with new suspension arms and Fiesta Mk3 front hubs was mounted onto a cast alloy rear beam that required a different fuel tank, boot floor pressing and the use of a spacesaver spare wheel.

Using this design met the objectives of having to minimise the modification of MTX75 gearbox and the CE14 floorpan as much as possible, but these restrictions also meant it was limited in terms of it's maximum power and torque handling (it was designed to handle an input torque of only 220Nm, and the RS2000 only produced 150BHP). The same system was also later developed for use in the Mondeo 4x4 (and Jaguar X-Type), but the transfer box was enlarged to allow larger, stronger gears to be used to allow a higher torque rating (280Nm), and the centre differential was modified to invert the torque split (60% front, 40% rear). As Bortaf has said, if you want to substantially increase the power in an RS2000 4x4, basically your only option is modifying a Mitsubishi Evo transmission (and the car to get it to fit). You can see in this picture the difference in the size of the centre diff and transfer case of the Evo transmission (on the left) compared to the MTX75 4x4 (on the right):

(there are also a couple of specialist suppliers who offer uprated internals for the standard transfer case to enable it to handle more torque)

Trying to convert a car that uses the MTX75 4x4 system to RWD only is not really feasible, if you want it to last. The transfer box and rear drive train were only designed to reliably handle 60% of the power and torque of the original application, and even if the centre diff was locked and the front driveshafts removed the geartrain would still have almost the same transmission losses as the full 4x4 system (unlike the Ferguson Formula system used in the XR4x4 or RS Cosworth, were removing the front propshaft, diff and driveshafts eliminates a large percentage of the 4x4 transmssion loss). Both Gordon Spooner Engineering and Andy Rouse experimented unsuccessfully with converting this system to RWD as part of the development of the RS2000 Formula 2 rally car and the Mondeo touring car, before reverting to the conventional FWD versions.

Would have to be Evo4+, the earlier Evo1-3 had the engine and transmission orientation reversed from the Escort and Evo4 onwards. The Evo1-3 boxes had the center diff housed inside the transmission while on the 4+ it was externally placed.

A mate of mine used to own one years ago. It went alright, if not exactly quick, but it went around corners very competently. Quite a surprising car in that respect.

Rare too, wasn't there something like only 500 made?

The full service manual with diagrams like the one above can be found here:

www.ossbegge.com/Dealer_Manual_4x4.pdf

I've often wondered about the possibility of using the MTX75 4x4 box from the Jag X-Type in an Escort or Focus, given the box itself is the 'same'.

There was nothing said about Evo gear, just standard Ford stuff. I'd imagine it was on borrowed time!