A month or so after doing the brakes I noticed a couple of drips of gearbox oil on the driveway. It seemed the 5th gear retaining nut had back out and cracked the end of the gearbox housing.
A quick torque up again and a bigger hit with the hitting stick on the 5th gear nut crush points seemed to solve it for the time.
A benefit of transverse mounted engine is that it is easy to replace the front gearbox cover, just jack the car up, take off the driver’s side wheel and there it is.
Now as luck would have it, when you own an odd ball car, owner’s kind of group together and someone not too far away from me had two KM221 gearboxes for sale with transfer cases, these are the standard Cyborg gearboxes with the 2.844 ratio diffs.
I borrowed one of the front covers from the gearboxes I had just collected, problem solved.
If you recall earlier in the thread I mentioned I had a habit of launching the car, well I had been itching to try this “stutter box” out and… well… when I did;
1. The output shaft of the transfer case snapped off.
2. A whole bunch of teeth on the rear diff crown wheel were ripped off.
Seems the on/off nature of the twin plate clutch and fused center diff attacked the next weakest links in the driveline.
It still drove that broken though, with the locked center diff it was just and open diff front wheel drive and it sucked, it would fry the front single wheel in 4th very easily and was basically unusable.
Thankfully though, I had a spare transfer from the gearboxes I picked up earlier and I also managed to source a 2.844 ratio rear mechanical LSD off retardme.co.nz, I’ve never heard of one let alone seen one for sale, score!
Speaking of ratios, VR4s/RVRs and Evo 1-3’s share a common set of rear diff ratios, 3.547, 3.909 or 3.312 for some Auto’s. The diff ratio doesn’t equate to the total final drive though as there is also a primary reduction ratio of 1.275 in the gearbox and a further 1.090 ratio in the transfer case which brings the total final drive 4.929 for 3.5’s and 5.433 for 3.9’s. Where am I going with this?
Well the pre-1990 Cyborg’s were the only series that had a 2.844 rear diff ratio and this is because they used a KM221 gearbox which has a different primary reduction ratio of 1.640. With the transfer case ratio of 1.090 this brings the total final drive to 5.084 very similar to a standard VR4’s.
Anyway, I digress, I put the spare transfer case in and swapped in the new rear LSD and it was good.