S40: GUIDE: Definitive cure for sloppy gear lever (Renault gbox)

[kilou]

Many S/V40 owners have experienced issues with gearshifts. Often these symptoms are caused by wear in the nylon bushings at the end of the gearshift selection rod. The known cure to this problem is to renew these bushings as explained in this excellent guide made by JSeaman:

http://www.volvoforums.org.uk/showthread.php?t=43008

Obviously renewing these bushings does work, is inexpensive and easy to do. New bushings will probably last for 100’000km so why bother? Because even with brand new bushings you get some faint slack since you cannot fully tighten the nut. As I was not happy with this design and wanted a definitive cure, the solution was fairly straightforward: install thrust bearings!

The idea is to replace the 2 nylon bushings with 2 small metal thrust bearings of the same size. Wear is minimal and the bearings are able to withstand a high axial load so that you can tighten the retaining nut on the selector to “press” the assembly between the jaws of the fork. The load is then transferred on the whole surface of the bearings and ALL free play is gone while the bearings allow for a smooth movement of the selector!!

Looking at nylon bushings, a good size for the thrust bearing is 10x20x5.5mm (read inner diameter/outer diameter/height). After a small journey on the web, the best match I could find was 10x18x5.5mm that come in a pack of 2 for about 17$…pretty good! Order placed here http://www.vxb.com/page/bearings/PROD/Thrust/Kit7156

The height of a bearing is exactly the thickness of a nylon bushing and the inner hole matches exactly the metal sleeve that goes through the bushings (you'll just need to grind the sleeve slightly).



So here we go for the install:

1. Jack the front of the car and support it on axle stands.
2. Access the assembly with nylon bushings and undo the retaining nut on the gearshift linkage


3. Pull the selector fork out and remove the bushing assembly (keep it in a safe place in case you want to undo this mod!)


4. IMPORTANT: Take the metal sleeve and grind a bit of metal (about 1mm) off its length. This will ensure that the whole load in the fork is carried by the bearings and not the sleeve. Also grind a bit each end of the sleeve (where the bearings will be placed) to allow the bearings to move correctly.
5. Wrap Teflon tape around the center of the metal sleeve up to a diamater of 1.2mm. This is to make the sleeve fit tightly in the hole of the selector arm. Make sure that you keep enough place on each end of the sleeve for the bearings!


6. Pack the bearings with a load of moly grease and place them at each end of the metal sleeve just as you would have placed new nylon bushings. Then carefully replace the selector fork over the bearings, fit the screw and the retaining nut and tighten it until there is no free play on the bearings.



7. Additionally you can place a plastic protection around the assembly to protect it from dirt/moisture and keep the grease inside. The plastic is attached with 2 zip ties.




Done!!

The difference is quite impressive for me: absolutely NO free play at all and the gearshifts are much more precise and feel lighter and smooth! I was concerned about vibrations in the lever with this mod since all freeplay is removed from the linkage...but definitely I have LESS vibrations than before so that's another good point! It’s even better than brand new nylon bushings and the “new” feel should last forever!

Happy motoring!

[Baffler]

Brilliant write up Kilou?

[kilou]

Originally Posted by kilou

4. IMPORTANT: Take the metal sleeve and grind a bit of metal (about 1mm) off its length.

By this I mean you need to shorten the length of the sleeve by about 1mm. The sleeve is then only used as a guide and allows the pressure on the fork (when tightening the nut) to be transferred on the bearings surface.

[alexx]

are these the same bearings in the uk for £12


JRH81017 : BRG THRUST 10 X 18 X 5.5
BRG THRUST 10 X 18 X 5.5


Price: £10.65 £12.25 Including VAT at 15%


http://www.modelhelicopters.co.uk/ac...s_JrHelis.html


if so im buying! thanks for the report mate

[kilou]

Originally Posted by alexx

are these the same bearings in the uk for £12


JRH81017 : BRG THRUST 10 X 18 X 5.5
BRG THRUST 10 X 18 X 5.5


Price: £10.65 £12.25 Including VAT at 15%


http://www.modelhelicopters.co.uk/ac...s_JrHelis.html


if so im buying! thanks for the report mate

Sounds similar but is it really metallic (it looks a bit cheap). Size is perfect however.

Note that you will have to get a new metal sleeve if you want to revert the mod as you'll have to remove 1mm off its length. If you already renew the bushes and the sleeve, use the old sleeve to do the mod.

[DutchV40]

If I select all the gears when standing still all gear shifts are fine. No problem.
Bushes are new, new gearbox and adjusted gear rod.

However when driving the shift from 2nd to 3rd gear goes a bit unsmooth. Just if you push something away 2 times. When doing it really slow ,waiting a sec just before entering 3rd it goes smooth.
From 4th directly to 3rd goes smooth however...

Any ideas?

[Clan]

Originally Posted by DutchV40

If I select all the gears when standing still all gear shifts are fine. No problem.
Bushes are new, new gearbox and adjusted gear rod.

However when driving the shift from 2nd to 3rd gear goes a bit unsmooth. Just if you push something away 2 times. When doing it really slow ,waiting a sec just before entering 3rd it goes smooth.
From 4th directly to 3rd goes smooth however...

Any ideas?

The first thing to do is change the oil , this has worked for me on a number of occasions when gears are hard to engage ( with no clutch drag ) Use the genuine oil from Volvo parts though .

[DutchV40]

Originally Posted by Clan

The first thing to do is change the oil , this has worked for me on a number of occasions when gears are hard to engage ( with no clutch drag ) Use the genuine oil from Volvo parts though .

The new box is already filled with new original volvo oil...

[kilou]

Originally Posted by DutchV40

However when driving the shift from 2nd to 3rd gear goes a bit unsmooth. Just if you push something away 2 times. When doing it really slow ,waiting a sec just before entering 3rd it goes smooth.

That syncro maybe needs a bit more time to mesh the gears properly. That may be an explanation. Personally I don't use the Volvo oil anymore, I got much better results with my current oil especially when cold.

But no worries, remember we have Renault gearboxes and no matter what we do we cannot get a perfect shift from these boxes. For example this thrust bearing mod will remove all the slack at the end of the selector rod (a small slack here translates in a large free play at the lever end) but it cannot remove the "built-in" free play of the fork inside the box.

The next mod I'd like to try eventually is a shorter rod at the gearbox end (the black item on the picture below):



This should also decrease the amount of free play at the lever and provide quicker shifts. But I'd like to try that if I can find one for dirty cheap because I'm unsure it would make the shifts smoother. Actually short shifts are known to be "sporty" i.e. not smooth....


PS: DutchV40, also if your gearbox is new, allow some time for it to "break-in". Gearshifts may become smoother after 10-15K km. On top of everything, renew the gearoil every 45K-50K km max, even in normal driving conditions.

[alexx]

What gearoil should I get then please, i got my car on 65k and its on 75k now and the gears feel like they dont slot in overly smooth they used to line up perfectly now its as if its just slightly off, always go in fine just noticable that its not smooth

ill try changing the oil and your mod first, just let me know which oils best

also is there anyway of changing the clutch engage point on these cars?