Hi guys Im in dia need of some help posted this the other day but really need to know if any of you can help me fix it /do it and course i would pay.

I bought a sierra sapphire with a 24v boa cosworth conversion last week, engine is sweet and fitted very well the problem is the gearbox jumps out of gears and the diff stops you dead at random times when in reverse, not really drivable.drove fine for the day i collected it

this it what i told it was running , but after speaking to dojj on here he dnt think so

Ok it's running a mt75 hybrid gearbox with an AP racing clutch a 2wd rs cosworth propshaft and the LSD and driveshafts are from a xr4i im no mechanic and need help if anyone on hear can help i would really be greatful and obviously pay you, garages down my way wont really wanna touch it, this sierra is mint so no old dog.

if anyone can help me fix this would be very greatful as i will pay