Thwaites All drive 7000 Leaking gearbox oil

[Soulman]

Hi

I had this issue recently which i resolved so just wanted to add some notes on the repair. So i noticed oil leaking from the bottom of the bell housing and it looked liked gearbox oil and i confirmed that the gearbox oil level was indeed losing oil. This All Drive 7000 is a 3 Tonne dumper with a Lister-Petter 3 cylinder engine and a Newage 3 speed Gearbox. The dip stick for the gearbox is attached to the top brass bung which doubles up as the oil filler cap for the gearbox.

So steps carried out:

1. disconnected the foot pedal throttle linkage.
2. remove the top access panel which sit over the gearbox, which is secured by 4 bolts/nuts.
3. disconnect the clutch linkage
4. remove the nuts and bolts securing the gearbox output coupler to the drive shaft.
5. remove the clutch coupling to the bell house lever.
6. remove the 8 bolts securing the bell housing.
7. gently pull the gearbox forward to disconnect the half shaft and lift out the gearbox/bell housing assembly clear of the machine
8. remove the clutch release bearing
9. remove the bolts securing the bell housing to the gearbox and slide the bell house away from the gearbox
10. drained the oil from the gearbox

At this point i could see the damaged shaft seal which was responsible for the oil leaking. I removed the half shaft from the gearbox. it just slides out and there will be a large bearing and a gear on the end of the half shaft. inside the gear there is a needle bearing and this has some signs of wear. I looked up http://www.davidcornwallis.com to see if the needle bearing and shaft seal were available. The shaft seal is available but the needle bearing has been replaced by a bushing bearing. I ordered the shaft seal, new bush bearing and the large bearing even though the large bearing was in pretty good condition from http://www.davidcornwallis.com. The parts arrived in a few days.

reassembly steps:

1. fitted the large bearing to the half shaft
2. fitted the new bushing bearing inside the half shaft.
3. refitted the half shaft to the gearbox (just gently tap it into place)
4. fitted the new oil seal to the bell housing (watch for correct direction of the seal)
5. bolted the bell housing back to the gearbox (take care not to damage the new oil seal while sliding the bell housing over the gearbox shaft.
6. refitted the clutch release bearing (replace this is it looks worn)
7. fill the gearbox to the correct level with gearbox oil
8. refitted the gearbox/bell housing back onto the engine mounting (bit of gentle manoeuvring to get the gearbox shaft splines to engage to the clutch coupler)
9. refit the 8 bolts securing the gearbox/bell housing to the engine
10. refit the clutch linkage
11. refit the drive shaft to the gearbox output
12. refit the top access panel which sits over the gearbox
13. refit the throttle linkage.
14. Recheck the gearbox oil level

Result, no more oil leaking from the gearbox and nice smooth running gearbox.

[cobbadog]

Well done.
it is satisfying when you take the time and care to do a job properly. Only difference I would have done, if possible is to drain the oil before lifting it out to save on weight and the same when refitting, oil in box after it was back in place.
Lately I haave rebuilt a few different toys, a tractor brakes which also meant removal of reduction boxes and a very old stationery engine. All oil seals were replaced and on the axle seals I was able to double up on the seals as there was room for 2 each siide but also fitted some speedy-sleves for the new seals to run on. In most cases my shafts had signs of wear with ridges so the sleeves cover that and make it like new.

[Soulman]

True Cobbadog about the oil although the Newage dumper geabox is only a tiny little chap with very little oil needed in it so wasn't a big deal on the weight and it was really easy to drain once i had it removed. If i was taking out a big gearbox with a lot of oil in it, id definitely take your advice . Good info on the speedy-sleves, good idea. Where do u get those from?

[essexpete]

So what is a speedy seal to an ignorant piece of turf like me?

[Jeremy Rowland]

So what is a speedy seal to an ignorant piece of turf like me?

Pete, we fit them at work sometimes; they are usually used where a seal has worn a groove in the shaft that it covers the basic idea is that the speedy sleeve seal has an additional surface on which the new seal that is part of it runs on, so it's a kind of cheap way to repair a worn shaft, saves getting a new one made or can save you stripping a machine or part thereof, that's the basic best description that I can give you.

Jeremy

[cobbadog]

Thanks Jeremy,
There are a few suppliers of these repair kits for many different applications but the main thing that is important is to accurately measure the OD of the shaft to be repaired. My D.B. 30C Cropmaster had some bad oil leaks from the axle seals that destroyed the brakes then the half shafts in the reduction boxes had slight grooves so I put the sleeves on all shafts.
When you unpack them from the box they are a very thin piece of drawn sheet metal with a small flange on one end. You work out what position you want the sleeve to sit on the shaft and then use a piece of pipe against the flange once you have started the sleeve then carefully bump the sleeve to where it needs to be.
I got caught out on the last job I did because the sleeve did not fit through the main bearing bush so I had to remove it and refit a new one. Once the sleeve is in position you use a pair of pliers and peel off the flange and it tears nice and smoothl away at a point where they have put a groove. These have saved many shafts around my place and have been 100% sucessful in stopping oil leaks.