Club 80-90 Forums

"Monty" is playing up, just after his succesful MOT
The gear started popping out of 5th under load when gearbox was cool last week. Replaced oil this week as suspected low oil level, it seemed to have planty in when I drained it, replaced it with 3.5 ltires Comma 80-90 gl4 stuff last week, (followed sir adventure blog guidance) gave it a test drive, gear popped out even more, So I returned home and researched and it said fill to brim 4.5 litres, so I did and test drove it and it seems better than with 3.5 litres but still pops out. If I hold it in gear its ok. What do you reckon I should try next. Drain plug had only a few fillings on it, not whole chunks of teeth and cogs so I'm hopful the gear box ain't goosed. Linkage? I can't see why it would start playing up now though and get worse with low oil level. maybe cog wear? Any one with any experience.

Standard JX gear box running from a steady aaz engine. All other gears seem fine. There does seem to be a very slight oil leak running from the junction of gearbox and cluth, I assume thats oil escaping from gear box.

Any advice gladly recieved

1. check through linkage, look especially for boots acting as springs when compressed especially the one on the cup and ball which if not split can ride up and get between the parts
2. make sure you are fully selecting the gear before releasing the clutch, ba abit deliberate about it see if makes a difference
3. hows the gearbox mount rubber is it allowing excess movement of the gearbox

if it keeps doing it then it may be either /or /or combination of mainshaft bearing displacement / worn dog teeth on gear and synchroniser, common problems especially on TD vans which get lugged in top gear using the torque of the diesel rather than dropping a gear and using the revs to pick up speed

Thanks to Aiden, seems sound advice, I've checked those things and the fact that I can put it in 5th, the gears all good and solid until I put just a certain amount of torque through it and it jumps out suggests its glory days are behind it. It makes no noise, works fine still and I'll continue driving around hopefully until I can get a replacement box. I guess if it's a loose baring this could further damage the gearbox and should be reduced as much as possible. Worn cog won't make much difference. I must confess the speed with which it went from the sporadic jump to popping out all the time has surprised me, it was quick. It still works if I hold the box in 5th, but I reckon this will just knacker the selector fork

I guess these are the options,

1 get a placement from eBay cheap from the scrapper, (cheap and uncertain of result)
2 Buy a reconditioned gearbox from the online market place (Expensive and without a good reputation uncertain in outcome)
3 Get mine reconditioned by a gearbox specialist (expensive but with a good reputation may make sense)

Basically I guess I'm looking for feedback and any suggestions/recommendations based on experience

holding it in will wear the selector fork, and the synchro slider but that is possibly worn so doesn't matter, but should have two hands on the steering wheel - obviously a certain social media T3 'celebrity' posted up a video of him using a bungy to hold it in gear, it's a viable short term solution, but will introduce more metal fines into the oil
if it is caused by broken selector fork bearings then it's a cheaper fix but longer left it does it less chance of saving the gear as once it starts popping out of gear the dog teeth edges become rounded over as they run over each other under load as it pops out, rather than usual change with no load on when you drop the clutch, disengaging drive, to change gear