LT77 gear box, Can't select gears

I have a LT77 gearbox.

I was reversing then went to change gear into 1st and couldn't.

Gearbox seems to be stuck in neutral, can no longer select any gear.

Gearstick still moves from side to side, ball joint still in-tacked.

Any idea's from anyone please?

Have you tried with clutch up and engine off? Try selecting hi, low, diff lock on and off

Yep, tried all that but no change.

With engine running you can hear the clutch engaged and dis-engaged so not sure if it's a clutch problem.

Sorry, what I mean is when you press the clutch pedal in and out. You can hear the gearbox turning or not.

its possible but if gear lever wont move to actual gear positions maybe not , yoke under stick turret can come loose ,pin in quadrants in box and on top selector housing can break ,you could also have pulled box selector pin between selector jaws ,actual info would be needed to narrow it down

sounds internal and needs further investigation

jamesmartin said:

its possible but if gear lever wont move to actual gear positions maybe not , yoke under stick turret can come loose ,pin in quadrants in box and on top selector housing can break ,you could also have pulled box selector pin between selector jaws ,actual info would be needed to narrow it down

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The yoke under the stick turret is ok. So does this mean the gearbox will have to come out for an internal inspection. Will I need specialist tools?

Have you tried it with diff-lock engaged ?

Might sound obviouse but if you had a broken half shaft/stripped drive flange would give you the same problem !

Not tried it but will do, Thanks.

Will report back.

Well ? Not done it yet ??

I had a similar problem a few weeks back with my R380 box, the gearstick would move (but didn't feel quite right) but it was stuck in 3rd gear. Clutch was working fine. Long story short, it was the grub screw in the selector quadrant that had backed out. Bit of a pain in the arse to do but it can be done with the box in situ. You will need to remove the transmission tunnel and I would loosen the bolts in the seat box too so it can be lifted slightly, just to give yourself a bit more room when you put it back together. Here's a pick of the grub screw, it should be in the detent hole on the bar to the right of it.

Jason2 said:

Well ? Not done it yet ??

Click to expand...

Sorry not had chance yet, life getting in the way. Will try tonight, although top half of gearbox is now in bits.

Selector grub screw is in place. That would have been a nice fix! Thanks anyway.

If the gearbox is clanked would you:

A: Rebuild it (are specialist tools needed?).
B: buy a second hand one.
C: I can't afford a recon one. so this isn't an option for me.

I appreciate your comments, thanks.

parchwba said:

Sorry not had chance yet, life getting in the way. Will try tonight, although top half of gearbox is now in bits.

Selector grub screw is in place. That would have been a nice fix! Thanks anyway.

If the gearbox is clanked would you:

A: Rebuild it (are specialist tools needed?).
B: buy a second hand one.
C: I can't afford a recon one. so this isn't an option for me.

I appreciate your comments, thanks.

Click to expand...

have you checked under gear box top ? as i said before it could be that youve pulled selector pin between selector jaws or reverse lever as come adrift ,both will need it pulling apart , which does need special tools and knowledge lt77 is much harder than r380 to work on, was every thing ok before ie gear changes ,noise or whinning etc and its just selection issue with the stick and not drive loss from some other issue like input gear and mainshaft spline wear etc ,i could fix it if it helped

jamesmartin said:

have you checked under gear box top ? as i said before it could be that youve pulled selector pin between selector jaws or reverse lever as come adrift ,both will need it pulling apart , which does need special tools and knowledge lt77 is much harder than r380 to work on, was every thing ok before ie gear changes ,noise or whinning etc and its just selection issue with the stick and not drive loss from some other issue like input gear and mainshaft spline wear etc ,i could fix it if it helped

Click to expand...

I've taken the top off but can't see anything amiss, not that I'm any expert. Can see one of the selectors looks ok, but shaft will not move forward fully. All gear changes were fine before except noticed that the clutch had always been sharp. Very hard to ride clutch.

No bad noises from the gearbox. Even now in neutral when the gearbox is turning no bad noises.

Tried putting it in high and low box but no change.

Well, The gearbox is out and on me workbench.

Drive shafts look brand new.

Does anyone know if I need a hydraulic puller to get the first bearing off or will a normal screw puller do the job?

Just an update for anyone interested.

I took gearbox apart and found the reverse gear shoe that selects the gear had come loose due to too much play. I have modified the shoe somewhat and have put the gear box back together again. All gears now work. Just got to find the time to put it back into "Charlie".....I hope.

I had it before where I pulled the top off the box to look at the selector mechanism and where I had out it in hear had jammed it on the rod so all looked good. Problem was staring me in the face tho, tightened the grub screw on the selector shaft and job done

Well gearbox worked for a couple of weeks but then I had the same problem as above. I didn't tighten the grub screw up correctly.

Now all is good.