Cant engage gear with engine running

Chadstone Pat · Jul 3, 2018

Hi all, I have searched the various forums but can't find anything that quite fits the bill. My 90/defender stopped going into gear with the engine running, no probs when engine stopped or when diff lock is in neutral. What I cannot understand is when I stop the engine then select a gear then start the engine with my foot on the clutch there is no drag and the clutch can be released normally. The engine is obviously still turning the gearbox but not enough to cause any drag when in gear.
I have bled it up and down and changed the master cylinder, before I get a slave cylinder does anyone have any thoughts ? Patrick

Kwakerman · Jul 3, 2018

Are you are sure the clutch is releasing properly as it sounds like the input shaft is still rotating? If so it could be down to worn baulk rings in the gearbox. They are a friction component and their job is to match the speeds of various gear / shafts within box to allow a gear to be selected. If they are worn then they can cause difficulty in selecting gears. Also check the gearbox oil level (or even replace it) as baulk rings rely on oil to work properly

Chadstone Pat · Jul 3, 2018

Kwakerman said:
Are you are sure the clutch is releasing properly as it sounds like the input shaft is still rotating? If so it could be down to work baulk rings in the gearbox. They are a friction component and their job is to match the speeds of various gear / shafts within box to allow a gear to be selected. If they are worn then they can cause difficulty in selecting gears. Also check the gearbox oil level (or even replace it) as baulk rings rely on oil to work properly

Thanks for your thoughts, the oil level is good, the box was refurbished about 10k ago so I would have thought it should be ok, is there a separate baulk ring for each gear ? as no gears are selectable with engine running.

Oldseadog · Jul 3, 2018

Give us a clue re your gearbox, is it an LT77, an LT85, an LT230, or what?.
Have you had it filled with EP80, EP90 or the ATF or MTF stuff?

Chadstone Pat · Jul 3, 2018

LT77 EP80 amongst others !

Brown · Jul 3, 2018

My experience with the R380 gearbox is that if there's any rotation at all getting through the clutch it won't select gears, even though there is not enough torque to move the vehicle. If you adjust the mechanism where the pedal is linked to the master cylinder so that the bite point is a bit higher, does that make a difference? Another thing that happens is that the clutch master and slave cylinder seals deteriorate so it doesn't separate the plates sufficiently. This is usually solved with new master and slave cylinders.

mikerajjers · Jul 3, 2018

I had exactly this problem on my series 3. The clutch spring plate was damaged and needed replacing.

wireman · Jul 3, 2018

''...If you adjust the mechanism where the pedal is linked to the master cylinder so that the bite point is a bit higher...''
I had a similar problem with my Lightweight, changed both cylinders, bled the system - no better, adjusted the pedal as per the Workshop Manual (140mm from the base of the pedal to the floor for a Defender - no mats) and it worked a treat (and still does)

Chadstone Pat · Jul 3, 2018

thanks for that, picking up a slave cylinder at 3 so will let you know if it makes a difference

Chadstone Pat · Jul 3, 2018

mikerajjers said:
I had exactly this problem on my series 3. The clutch spring plate was damaged and needed replacing.

new clutch about 3 months ago but that does'nt mean a thing I suppose

jamesmartin · Jul 3, 2018

Chadstone Pat said:
LT77 EP80 amongst others !

lt77 should have dexron 2 or 3 not gear oil,the coated baulk rings will be destroyed,reverse is a sliding gear so not affected by wrong oil,its either the oil in the box or clutch not clearing,which can be hydraulic side or clutch cover itself

Chadstone Pat · Jul 3, 2018

wireman said:
''...If you adjust the mechanism where the pedal is linked to the master cylinder so that the bite point is a bit higher...''
I had a similar problem with my Lightweight, changed both cylinders, bled the system - no better, adjusted the pedal as per the Workshop Manual (140mm from the base of the pedal to the floor for a Defender - no mats) and it worked a treat (and still does)

Try all lengths, finished with it wracked right out to the end to get a bit more throw.

Chadstone Pat · Jul 3, 2018

jamesmartin said:
lt77 should have dexron 2 or 3 not gear oil,the coated baulk rings will be destroyed,reverse is a sliding gear so not affected by wrong oil,its either the oil in the box or clutch not clearing,which can be hydraulic side or clutch cover itself

Cant get reverse either, Hmn... I'd be supprised if all the rings went at the same time, slave cylinder may make a difference will know shortly. Thanks for your reply

jamesmartin · Jul 3, 2018

Chadstone Pat said:
Cant get reverse either, Hmn... I'd be supprised if all the rings went at the same time, slave cylinder may make a difference will know shortly. Thanks for your reply

they can as ive seen,rebuilt boxes with destroyed baulk rings after few miles,but reverse affected on an lt77 says clutch isnt clearing

Kwakerman · Jul 3, 2018

Chadstone Pat said:
Hi all, I have searched the various forums but can't find anything that quite fits the bill. My 90/defender stopped going into gear with the engine running, no probs when engine stopped or when diff lock is in neutral. What I cannot understand is when I stop the engine then select a gear then start the engine with my foot on the clutch there is no drag and the clutch can be released normally. The engine is obviously still turning the gearbox but not enough to cause any drag when in gear.
I have bled it up and down and changed the master cylinder, before I get a slave cylinder does anyone have any thoughts ? Patrick

Another thought, could be the spigot bush in the flywheel has partially seized to the input shaft, that would cause the input shaft to spin with the clutch disengaged, was it changed when the box new box / clutch was fitted?

Chadstone Pat · Jul 3, 2018

Kwakerman said:
Another thought, could be the spigot bush in the flywheel has partially seized to the input shaft, that would cause the input shaft to spin with the clutch disengaged, was it changed when the box new box / clutch was fitted?

I had thought about that. It was changed, and there was none of the usual noise associated with bush failure.

Chadstone Pat · Jul 3, 2018

Ok, so changed the slave cylinder and no change. bled both ways. Any thing else I can try before I hoick the box out?

wireman · Jul 3, 2018

Chadstone Pat said:
Try all lengths, finished with it wracked right out to the end to get a bit more throw.

I did the same, then measured it, adjusted it correctly and it worked. Set the pedal to 140mm then you know that is right.

Chadstone Pat · Jul 3, 2018

wireman said:
I did the same, then measured it, adjusted it correctly and it worked. Set the pedal to 140mm then you know that is right.

worth a try

Chadstone Pat · Jul 3, 2018

Chadstone Pat said:
worth a try

Nope

Cant engage gear with engine running

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