jerboa Posted July 4, 2011 Share Posted July 4, 2011 Hi there (again) I've had a scour of the forum and cant seem to find anything that relates specifically to this problem.. I'm seem to have a slight issue with the gearbox in my '81 109 Series Three.. 110,000 miles (if it hasn't gone round the clock twice) At low rpm with moderate to heavy load in third and fourth (only) there is a very loud and intrusive chatter or rattle that emanates from the gearbox. It sounds like the internals of the box are wobbling eccentrically and are going to fall out. It also occasionally pops out of third and fourth on the over-run when heading down hills. I might need to rebuild the box, any diagnosis of what the problem maybe before I get there?? Cheers, Alec.. Quote Link to comment Share on other sites More sharing options...
Chris x Posted July 4, 2011 Share Posted July 4, 2011 I also have this (although mine doesnt jump out of gear). Its been like it for a while though, and has never really bothered me. Would be good to know what it is though! Quote Link to comment Share on other sites More sharing options...
ejparrott Posted July 4, 2011 Share Posted July 4, 2011 I have a lot of noise in 1, 2 & 3, all with or without OD, but fourth and fourth+OD is quiet. I'm convinced mine is because the layshaft bearings have gone, as again its under load, and fourth doesnt use the layshaft. I would have said yours was the same but for it doing it in fourth. It could still be that its the layshaft bearings I suppose, more knackered than mine.... Did the noise come suddenly, or has it been coming on gradually? I take it its the Series 4-speed? Quote Link to comment Share on other sites More sharing options...
secondjeremy Posted July 4, 2011 Share Posted July 4, 2011 They do tend to seem to chatter and surge at very low revs. I first noticed this is a S2a fitted with a Prima diesel and 3.54 diffs - which wouldn't really run at 30 MPH in 4th. There was nothing wrong with the gearbox as I'd just rebuilt it with a new layshaft and many other parts and otherwise it functioned perfectly. As confirmation my S3 diesel (standard transmission) does much the same at around 15 MPH in top but is Ok above that. Its not really noticeable as its quite pointless running the thing that slow in 4th as to get it to move you've got to change down to 2nd. The transmission on this vehicle is nice and quiet and changes gear properly. If its dropping out of gear it may be worth dropping the top and rear covers off the transfer box and making sure the nut on the back of the mainshaft is really tight (100lb ft) On most if not all the boxes I've dismantled its been loose. It holds the mainshaft in position as well as locating the individual components on the shaft and if loose they can run up and down the shaft - which may cause it to drop out of gear. Quote Link to comment Share on other sites More sharing options...
Snagger Posted July 4, 2011 Share Posted July 4, 2011 I have found that SIII gear boxes chatter progressively more loudly the higher the gear selected (including 4th) at idle with the transfer box in neutral. This is both on my older boxes and the 109's box immediately after a full and painstaking rebuild (£400 just on parts). I find it less pronounced but still evident when driving at very low rpm (<1000rpm). Quote Link to comment Share on other sites More sharing options...
jerboa Posted July 5, 2011 Author Share Posted July 5, 2011 Maybe I should just put up with it, the previous owner said he had replaced the bearings and seals etc - but to what end?? I will check that nut.. Quote Link to comment Share on other sites More sharing options...
hazzalandy Posted July 7, 2011 Share Posted July 7, 2011 mine used to do this, I just tightened up the selector rod tie down thingys and it hasnt done it since! Quote Link to comment Share on other sites More sharing options...
danster Posted July 7, 2011 Share Posted July 7, 2011 mine does exactly the same noisey at low revs in 4th and drops out of 3rd gear on over-run thought it was just the 200tdi taking its toll! Quote Link to comment Share on other sites More sharing options...
secondjeremy Posted July 7, 2011 Share Posted July 7, 2011 I think you'll have to put up with it - I think its endemic. What causes it I don't know - may be something to do with the rather heavy flywheels Land Rover use, slack in the whole system due to the design - but they do it in top so this seems unlikely. As my S3 diesel does it it can't be the sheer brute power of the things. As petrol have different mountings to diesels it seems unlikely to be much to do with them, very early S2 LWB diesels had a small flywheel bolted onto the handbrake drum - which was forgotten about later - it was described as a damper - what it did I don't know. These would have been the infamous 2 litre diesel. Quote Link to comment Share on other sites More sharing options...
Snagger Posted July 8, 2011 Share Posted July 8, 2011 I think you'll have to put up with it - I think its endemic. What causes it I don't know - may be something to do with the rather heavy flywheels Land Rover use, slack in the whole system due to the design - but they do it in top so this seems unlikely. As my S3 diesel does it it can't be the sheer brute power of the things. As petrol have different mountings to diesels it seems unlikely to be much to do with them, very early S2 LWB diesels had a small flywheel bolted onto the handbrake drum - which was forgotten about later - it was described as a damper - what it did I don't know. These would have been the infamous 2 litre diesel. It's due to the clatter of the unladen main shaft gears - the idling speed of the input pinion and lay shaft are the same, but the main shaft speed varies with gear selection. The lay shaft gears are integrated with the lay shaft so can't clatter, but the main shaft gears are free to rotate on their shaft unless engaged and their baulk rings are relatively loose. I had never heard of the SII 109 hand brake damper, though. It may have been to reduce engine and transmission vibration in much the same way as the Discovery II's mass damper on the back of its LT230. Quote Link to comment Share on other sites More sharing options...
task Posted July 9, 2011 Share Posted July 9, 2011 My Series 3 V8 clatters in 1st/2nd but not in 3rd/4th. The box was rebuilt using all new bearings etc so not sure it's that. It's always done it and has lasted 2 years like this so not overly worried, it does make me a little hesitant to give it much stick in those gears. Probably not a bad thing! Quote Link to comment Share on other sites More sharing options...
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