LT95 2nd gear problems

[HotWired]

My 110 County has had a problem with 2nd gear as long as i can remember.

Its runs smoothly up through the gears, but when coming back down from 3rd to 2nd it grinds teeth and wont go in. Unless im going about 20km/h then it shifts fine.

Late last year i decided to change the synchro between 3rd and 2nd (along with bearings). All looked fine, second gear teeth where a little worn but nothing serious.

Put all back in, and ran it with a 15w40. But still having the same problem. Im now running a 20w50, but no changes.

Any ideas on what could be causing this?

One suggestion was milling the face of the synchro down slightly so it puts more pressure on the gear.

Regards

Sean

[Bearman]

G'day Sean,
15W40 is what is recommended for these boxes, anything above this is too thick and likely to damage the oil pump. With the gear grating it is most likely wear/damage on the gear, synchro ring or the synchro collar itself. The engaging dogs on the gear and synchro sleeve may be chipped/worn on the points from grating. When you say you replaced the synchro unit do you mean the brass synchro/baulk ring on the gear or the steel synchro collar on the mainshaft with the straight cut teeth (for reverse gear) that engages 1st and 2nd gear. 3rd gear is on a separate synchro unit that shifts between 3rd and 4th. Buy genuine synchro rings as I have found some aftermarket ones are not up to scratch and sit too low on the gear. Another tip is to buff the shiny tapered face on the gear that the synchro ring contacts with fine emery paper.This will help the synchro ring stop the gear. Also check that the endfloat on the front section of the mainshaft is within specs. All this requires removal of the box to rectify. Otherwise double clutch when downshifting if you don't want to drop the box.

[HotWired]

Thanks for the reply

Next service Ill be going back to 15w40. With the synchros it was the brass synchro/baulk ring that I changed.

For now Ill continue to double clutch. Once I get enough enthusiasm to drop the box again, Ill look at replacing the gear, synchro ring and the synchro collar.

If that doesnt work Ill upgrade to a truck box.

Thanks for your help

Sean

[101RRS]

If that doesnt work Ill upgrade to a truck box.

What is a 'truck' box?

[HotWired]

A few others with the Isuzu engines are putting in the Isuzu MSA gearboxes

[101RRS]

A few others with the Isuzu engines are putting in the Isuzu MSA gearboxes

Ok - you had not mentioned it was an Isuzu county.

Good luck with it.

Cheers

Garry