peter8315

Active Member
Just changed my gearbox to one I thought was good, and it’s making a loud grinding noise, only reversing
 
Grinding is not good (in a gearbox anyway!) I'm no gearbox specialist but I'd say its a bearing issue. Those that have tried have said series gearboxes are simple beasts and are (fairly) simple to work on. Doesn't help your frustration though of having to take the gearbox out again. (or never go backwards) Is it full of the correct oil?
 
Take the selector shafts top off and have a look at position of selector fork.
Also what variant box is it as some have a reverse stop bolt on the selector shaft end fitted through transfer case.
Bolt is on most as a blank need to lift the little plate of selector cover to see if it is full length and in contact with selector shaft when reverse selected.
 
The reverse stop screw was missing on my SIII when I bought it. (I strongly suspect that the owner's suspicion that he had a failed gearbox played right into my hands when negotiating the price). Symptom was grinding and banging in reverse.
 
The reverse stop screw was missing on my SIII when I bought it. (I strongly suspect that the owner's suspicion that he had a failed gearbox played right into my hands when negotiating the price). Symptom was grinding and banging in reverse.
Hi mate, is that on the gate, just under gear lever
 
Hi mate, is that on the gate, just under gear lever
No, if you're looking down on the top, the transfer box has a big flange that comes up to cover the back of the gearbox, and the screw is in a little recess on the back of that - goes through to meet the back end of the reverse shift rod.
 
Useful advice, mine makes that noise as well. Currently way off the bottom of the list but will have to be looked at eventually...
 
No, if you're looking down on the top, the transfer box has a big flange that comes up to cover the back of the gearbox, and the screw is in a little recess on the back of that - goes through to meet the back end of the reverse shift rod.
Ok mate, just got around to it, so I’ll heck that out, thanks, Pete
 
No, if you're looking down on the top, the transfer box has a big flange that comes up to cover the back of the gearbox, and the screw is in a little recess on the back of that - goes through to meet the back end of the reverse shift rod.
Hi mate, have found the bolt that you referred to and it ca be adjusted by loosening the lock nut on it, I have tried adjusting it in many positions but still grinds,
 
Well still got nowhere with this thread, thanks for your input, but I think Wireman is pointing me in the right way, and is it easy job to change bearing on reverse shaft end, I think the bearing has collapsed allowing cog to partially slip.
 
Take the selector shafts top off and have a look at position of selector fork.
Also what variant box is it as some have a reverse stop bolt on the selector shaft end fitted through transfer case.
Bolt is on most as a blank need to lift the little plate of selector cover to see if it is full length and in contact with selector shaft when reverse selected.
I have checked the reverse shaft stop bolt and that’s ok, but I will check the selector fork position tomorrow, thanks for your advice.
 
I'm not a gearbox 'expert' but have rebuilt a few.

Reverse gear only has a plain bearing, and I can't see that being a problem - it's the lowest thing in the box and if lack of/tired oil was the problem it would still be fine even if all the other bearings were shot.

It's possible that the pinch bolt (which also locates the fork by way of a cut out in the shaft) has come loose, and that's easy to check by taking off the top cover. The selector shaft is located by springs and balls - also under the top cover) and if missing or weak could let the selectors move about, but I think you'd have noticed that varying the gear lever position had an effect on the noise.

My guesses though would be that one of the other bearings is failing or that you've got some very bad wear on gear teeth.

Let's call @jamesmartin - who is a gearbox expert.
 
Thanks for that I am in the process of checking the fork status on the reverse shaft,I was hoping James Martin might see this thread.
 
I'm not a gearbox 'expert' but have rebuilt a few.

Reverse gear only has a plain bearing, and I can't see that being a problem - it's the lowest thing in the box and if lack of/tired oil was the problem it would still be fine even if all the other bearings were shot.

It's possible that the pinch bolt (which also locates the fork by way of a cut out in the shaft) has come loose, and that's easy to check by taking off the top cover. The selector shaft is located by springs and balls - also under the top cover) and if missing or weak could let the selectors move about, but I think you'd have noticed that varying the gear lever position had an effect on the noise.

My guesses though would be that one of the other bearings is failing or that you've got some very bad wear on gear teeth.

Let's call @jamesmartin - who is a gearbox expert.
Hi mate, have checked fork and retaining bolt, all tight, so I am taking gearbox out and trying one I have found in my store, it seems to get all gears, but going to put in with a couple of bolts and try it.
 

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