Series 3 Gearbox stuck in 3rd, 1972 88

Hi everyone,

A couple days ago whilst accelerating, I attempted to shift from 2nd into 3rd, and encountered some resistance. Believing it was a mis-shift, I moved the lever into neutral, and was able to engage 3rd relatively easily. Unfortunately, it's since been stuck in that position since.

Uncertain of the fault, and not wanting to cause further damage, I haven't given the lever a good pull. I did notice it was rotating excessively immediately afterward, the grub screw was partially dislodged.

The clutch does operate correctly, and I was able to drive it home (1/4 mile away, fortunately). There are no unusual sounds, vibrations, etc., and is otherwise functioning properly.

I've since removed the top covers, and everything appears to be in order: ball bearings correctly in place, reverse springs are ok, and synchro detent springs appear to be properly fitted and undamaged (the backside was examined with a mirror).

Both the 1/2 and 3/4 selector rods were essentially frozen, with very limited travel. After a few mm of movement, they abruptly stop. Same situation when manually operated without the forks.

Perhaps the excessive lever rotation somehow gummed up the works?

Here are side-by-side photos showing the maximum amount of movement:


Present condition of rear:



Any ideas?

I haven't a clue about diagnosing these sorts of problems, maybe overlooking something simple? Re-install the lever, cross my fingers, and fiddle with it a bit? The goal's not to cause further damage!

Any guidance would be greatly appreciated, thank you.

nvalentino said:

Hi everyone,

A couple days ago whilst accelerating, I attempted to shift from 2nd into 3rd, and encountered some resistance. Believing it was a mis-shift, I moved the lever into neutral, and was able to engage 3rd relatively easily. Unfortunately, it's since been stuck in that position since.

Uncertain of the fault, and not wanting to cause further damage, I haven't given the lever a good pull. I did notice it was rotating excessively immediately afterward, the grub screw was partially dislodged.

The clutch does operate correctly, and I was able to drive it home (1/4 mile away, fortunately). There are no unusual sounds, vibrations, etc., and is otherwise functioning properly.

I've since removed the top covers, and everything appears to be in order: ball bearings correctly in place, reverse springs are ok, and synchro detent springs appear to be properly fitted and undamaged (the backside was examined with a mirror).

Both the 1/2 and 3/4 selector rods were essentially frozen, with very limited travel. After a few mm of movement, they abruptly stop. Same situation when manually operated without the forks.

Perhaps the excessive lever rotation somehow gummed up the works?

Here are side-by-side photos showing the maximum amount of movement:

Present condition of rear:

Any ideas?

I haven't a clue about diagnosing these sorts of problems, maybe overlooking something simple? Re-install the lever, cross my fingers, and fiddle with it a bit? The goal's not to cause further damage!

Any guidance would be greatly appreciated, thank you.

Click to expand...

https://forums.roversnorth.com/show...gear/page2&s=491021d85e89fa9f6dec3ffa08bac23a

If you put the transfer gear lever in neutral you should be able turn the gear train when foot on clutch, there will be some load as the transfer gears will also turn. It should be possible to select a gear doing this as the syncro cones line up. [ does take a bit of effort and a flat bar or even hand held fork may be needed.] If this works then check rods are free to move where the exit the box.
Have even known a stone landing in the selector box area cause a problem like this.

Try the mainshaft nut, accessable from the PTO cover, assuming no overdrive.

Thanks for the replies and insight, happy to report the gearbox is sorted!

It was ultimately faulty detent springs on the 3/4 synchro, but not in the usual manner (snapped, clearly jammed, etc.). A careful visual inspection revealed no obvious faults, and all three appeared properly aligned/centred. I came across a thread stating they occasionally appear fine, yet have concealed damage.

Whilst waiting for the castellated socket to arrive, I attempted to remove the detent springs, hoping to at least engage a gear. After rotating all three 90° in place, it was clear they were fully intact. So I returned them to the original positions, reassembled the cover/lever, and the gearbox is operating better than new. There was a fair amount of fiddling/bending during this process, as there was no intention to reuse them. That may have unintentionally solved the problem.

She was fully restored in Italy to a fairly high standard, but there are a handful of Britpart bits (can be difficult to find spares locally, and lots of items need to be imported). I don't believe these springs to be genuine, so perhaps they're out of tolerance?

Regardless, if you're encountering the same problem, closely examine the springs, and try moving them to check for hidden defects.

Thanks again, everyone.