Thwaites dumper gearbox problem....

[farmer boy]

ps - any idea where I can find a breaker in case a replacement box is needed?

[farmer boy]

Just realised I still have no idea which model it is! Can anyone identify it from the pics below please? Thanks..

[FOWLER MAN]

Hi,
It's many years since I repaired one of these boxes so it's difficult to remember the detail, but the missing bush you refer to in the primary shaft was probably a needle bearing race.
The absence of this race and sloppy input shaft bearing would have allowed the mainshaft to lift and its gears would have slipped out of mesh with the leyshaft gears causing the symptoms you discribed in your earlier post. 1st and 2nd would suffer first
because these gears are at the end of the shaft which would lift most.
A rebuild with new bearings may well sort it out, but you will have to judge for yourself the extent of any damage caused to the gears, they need not be perfect to run satisfactorally. You may well get away with small chips and a little wear in the teeth.
More pics. please.
You should manage without a press, but a bearing puller kit may be usefull.
Good luck.
Fred.

[farmer boy]

Many thanks Fred - that all makes sense... you are right about the bush being a needle roller - (I have just downloaded the workshop manual for the gearbox)... bloody thing must have disintegrated! The rest of the box does seem to be fine... I only drove it about 20 yards when it was making the awful noise so I may have averted too much damage.
The workshop manual seems to show the input shaft complete with the gear - so maybe it is a single piece unit... ie not a separate gear that fits onto the input shaft?
Anyway its too hot today - I have been sweating like a pig and I will need to try to find a supplier of replacement parts... who do (did) you use?

Thanks again for your help - much appreciated.

[FOWLER MAN]

Hello again,
Your right, there is no seperate gear on the primary. This shaft may also be refered to as the first motion shaft, or spiggot shaft).
You should be able to get bearings and seals from yor local bearing supplier, should be much cheaper than a Thwaits outlet. If you take the shafts with you they should be able to measure for the missing bearing, unless you are able to do that yourself.
Fred

[farmer boy]

Thanks Fred.... I will check out a local bearing supplier on Monday and see if they can remove the old and fit the new for me. Still attempting to get rid of the filthy grease on my hands - must remember to buy swarfega!

Do you know what model my machine is?

[farmer boy]

Well, the replacement input shaft has arrived (£150.00 - ouch!) and what I thought was wear on the teeth is actually how they are! Must be to aid gear selection I think. I still need it though because the other end of the old shaft is badly worn where the needle roller bearing had disintegrated! I will fit all new seals and bearings in the gearbox. I have ordered a set of new filters and a new rubber cover for the gearstick - stop the damn water getting in again - I will give it a full service when it is back together.
In the meantime I have bought a new one... 2 ton, all drive with power swivel and a water cooled 3 cyl Yanmar engine - its like a Rolls Royce compared to the old one! I will put my old one up for sale when it is fixed. Any idea what sort of price they are fetching?
Here are a few pics of the new one...... anyone know what model it is? I think it is 2003.

ps... the new machine whines a bit - not bad, just the normal transmission whine that you get when reversing (but in all gears on this one) - is this normal? I have checked all the oils and all is well. Maybe the noise is more apparent because the engine is SO quiet! It as sweet as a nut and starts on the button.. the joys of electric start!!!!

[daleyg12384]

Farmer boy,Do you know what model of box is in your old dumper?should be on a plate on top of gearbox next to selector.I think your old dumper looks like a Thwaites.
I have an old Benford TT2000 which has a 3cyl Lister and a Newage 40MJ gearbox,any chance you could send me a copy of your workshop manual?
I have serious gearbox issues,got no 2rd and 3rd,took top off box to discover it was full of water and selector was mashed,then drained water and oil and found some needle roller bearings!!!! :O
however does look like it may be easy to strip,where did you get your parts from?

Cheers Dale

[farmer boy]

Hi Dale... I am afraid I have sold it and gave the manual and all the bits to the new owner... I downloaded the manual for free - Newage website I think? The parts were from an online supplier... I have searched and searched my mail and history but cannot find any details.. I gave all the paperwork to the new owner... bugger - not much help - I know..!
Mine had same symptoms.... the rubber seal on top was knackered and let rain water in and eventually the main input shaft needle bearings gave up the ghost... I even bought a new input shaft but did not need to - be warned that the teeth on the gear look as if they may be badly worn but it is designed that way! If I can remember where I got the bits I will let you know... sorry cannot be more helpful.

[Julian]

be warned that the teeth on the gear look as if they may be badly worn but it is designed that way! l.

If it's not a constant mesh gearbox (like mine) then the gears are chamfered to facilitate engagement, you should have stuck a picture up!

Julian.