I've got the same problem in that I can't get reverse on my F28 that I've fitted in my 2wd chassis Calibra (I took out the c20xe/f20 and put in a c20let/f28). I've converted it to 2WD, LSD was fitted by V-tunning.
I have a 1993 chassis which means gear selection is easier (ie stick 5mm drill bit in F28 (neutral) and 5mm drill bit in gear stick hook (neutral) and eveyrthing is in neutral).
So I've done all this, all the forward gears engage the front wheels all spin round, the clutch engages fine as you lift up the clutch, it bites, revs drop but come back up agasin. But in reverse, the wheels are still going forward.
I thought it might be the LSD as the front is still up in the air via axle stands. So I put it back on the ground, all forward gears make it go forward, stick it in reverse, it still goes forward. I take it reverse is still in the same place as my F20, ie top left had corner by lifting up?
You guys have mentioned you've fixed it, but not saying exactly how. Tweedling with the gear slector sounds very time consuming when your working this on your own. At the gearbox end, where abouts is reverse as its not stamped on the gearbox housing like it was on the F20?
Plus the reverse lights do not work when I put it in reverse. I have read something about connecting the c20let reverse loom plug into the car reverse loom plug and connecting that into the reverse f28 connecotr, is this true (never heard it until I read an old post on migweb).