I have just removed the gearbox from my 91 'H' reg 3 door disco it's the 2.5tdi. I lost all drive one day while sat on the motorway at 70mph. I found i was able to select gears without using the clutch but i couldn't get drive no matter what. So i braved the snow and the cold and i've taken the box off. The clutch looks fine and doesn't appear to be damaged in any way. I split the gearbox and transfer box to check all the slpines which appear good. Witht the box's seperated i tried turning the input shaft to see if the gearbox output shaft would turn and it didn't. I chaecked it's in gear tried again and nothing still. I believe that something has obviously gone inside the box but am wondering if there's any common faults that it might be.

try it in 4th gear as input pinion and lay shaft front gear can loose their teeth ,also check clutch center really carefully

Ive tried it in 4th and lo and behold it works in 4th not in any other gear though.

thats because input teerh have gone it would have to be rebuilt ,sometimes damages front casing often caused by poor or lack of oil,more common oon r380 gear box 4th gear occurs when input is connected to main shaft ,all other gears go through layshaft first,no drive to layshaft no drive in any gear apart from 4th

jamesmartin said:

thats because input teerh have gone it would have to be rebuilt ,sometimes damages front casing often caused by poor or lack of oil,more common oon r380 gear box 4th gear occurs when input is connected to main shaft ,all other gears go through layshaft first,no drive to layshaft no drive in any gear apart from 4th

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Your spot on mate thats exactly whats happened, took the box to a transmission specialist he said the front bearings had welded themselves to the shaft. He said it's not worth rebuilding and that it probably wouldn't even be excepted for an exchange. If anyone knows anyone selling a gearbox for a 1991 disco 2.5 tdi please let me know.