5 speed punto gearbox
From a gearbox builders perspective this is one of the more simple gearboxes. Easy to take apart with only a few tools. Upgraded bearings are readily available for the input shaft and main shaft (pinion). The original bearings are just ok, not built for longevity. (New puntos have failed with less than 20,000 miles on the clock). The input shaft front (nearest the clutch housing) bearing is not a million miles away from what you might find in a washing machine! You can see a built gearset above with upgraded front bearing & pinion bearings ( cylindrical rollers as opposed to the OE ball bearing which fail much quicker). You can also see part of the fork assembly attached & ready for insertion into the clutch housing (AKA) front case. It’s standard for National Gearboxes to always use the stronger upgraded bearings in all punto petrol engined 1.2 or 1.4 5 speed & the extended 6 speed box
With the correct tools total strip is 10 minutes or less. (I have built 100’s of these).
Uniquely for a gearbox company, I will show you & explain how we do it at National Gearboxes!
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Author: Jay Richards , Managing director, National Gearboxes Ltd. Image copyright: Jay Richards
Strip the gearbox for inspection.
- Drain all oil
- Undo the 5 x 13 mm bolts that hold the turret on
- Tap the weight on the selector upwards with a copper hammer
- Undo the 10 mm bolts that hold the 5th gear lid on
- With a flat metal scraper carefully chisel the 5th gear lid off
- Undo the 10 mm bolt that holds the 5th gear fork onto the selector shafts
- With an air gun undo the two nuts that retain the 5th gears
- Remove the 5th gears & hub & fork ( be careful not to chip the gears)
- Remove allen-key-bolts that hold down the end plate.
- Remove the 2 cir-clips on the input shaft and main shaft.
- Your are now ready to deal with main case.
Main case strip down
- Undo all the 13mm bolts that secure the mid case to the clutch housing
- Undo 1 X 13mm bolt in the side of the mid case that secures the reverse idler shaft
- Undo the 4 x 13 mm bolts that secure the output seal flange
- Undo the 4 x 13 mm bolts that secure the diff housing
- Undo the larger 4 x 14 or 15 mm bolts
- With a copper hammer gently tap of the Diff housing
- The crown wheel will fall out
- With a copper hammer (if needed) tap of the diff output flange keep the shim
- Remove main case
Gearset Removal
- Undo the 2 x 13mm bolts that retain the reverse fork
- Remove fork & reverse gear idler with the shaft /post
- With both hands lift out the main shaft & laygear
- You are now ready to strip the gearset
Laygear-shaft stripdown
- Special tool needed, bearing splitter
- Preferable to use a hydraulic press. doesn’t need much tonnage
- Attach the splitter to the top laygear bearing it will sit in the bearing grooves on the outside
- Place in a press and push the shaft downwards, away from the splitter.
- the sleeve that 5th gear runs on will also come off
- You are now ready to remove 4th gear
4th gear removal
- With the bearing and sleeve removed 4th gear & the syncro will simply lift off
- Inspect the dogs on 4th, they should be sharp if they look worn this gear will need changing
- Put the syncro on 4th and spin it on the gear to ascertain whether it feels like it will work
- You need to do this with both hands and apply pressure, you counter rotate
- Look at the syncro and inspect it should look sharp
- The windows on the syncros should be without wear
- When windows are worn on syncros it can make for difficult selection
- The windows are what the detents or shift plates move into
- Early Puntos use roller and springs
- Later Puntos use shift plates, much easier and less fiddly
- The earlier gear sets are coarser and wear less
- The job of the syncro is to slow the gear down during a gear shift
- Carefully remove the circlip that holds the 3-4 hub onto the layshaft
- A word of warning, the more times the circlip pliers jump off the clip, the harder it gets!
- You are now ready to remove the 3-4 hub
3-4 Hub Removal
- With the circlip removed place the shaft back on the splitter
- It needs to be positioned so that it sits on the bottom of third gear
- Push the shaft through with the press
- It will also remove 3rd gear & hub at the same time
- On the bench carefully de-spring the hub push the inner out
- Retain all the (3) springs & (3) rollers or the 3 shift plates ( detents)
- Inspect the hub for wear if worn it will need changing *3rd & 4th issues are really common
- You will also need to clean out all the swarf from both parts of the hub* dull silver almost paste like
- Use a degreaser or paraffin, brake cleaner and a small wire brush
- Once the 3-4 hub & 3rd gear is removed you are ready for the final stage
- The conclusion to this will soon be on YouTube.
- Our channel is https://www.youtube.com/channel/UCKsEafhlYyx0pXdaUhFYEKA