300TE-24 speedo drive gear problem
New to forum. Yesterday my speedo stopped working on my '90 300TE-24v. Traced the fault to a broken plastic drive gear in the rear casing of the transmission (4 sp auto). My Merc dealer quotes £1200+ to fix - says the trans has to come out. I don't think it has to. It looks as though the rear casing can be removed in situ. Before I have a go at it myself any advice would be appreciated.
Thanks in advance