Gear Change issues

[DavidHill]

The saga with getting my Aprilia back on the road continues! 

After having to take the entire back axle off to change the wheel bearing, i finally axle on the car and everything connected on New Years day.  I was tempted to drive it to Brooklands meet...but decided to first drive it locally. (a good decision in retrospect!) I drove round the block here 5 times (around 6 miles in total and then at speed down a short piece of dual carriage way (not sure what speed as speedo not currently connected - but estimate 50-55mph).  As i came off the dual carriageway i found it hard to come out of 4th...and then 3rd...but figured maybe time to go back to home and rest....this morning i managed about 2 miles and then found i could not get out of 4th, and when i did get it out, found 3rd v hard to get into...and on limping home in second and parking up found i can no longer select 3rd, 4th or 1st whilst stationary.  Even after i let the car/gearbox cool right down i still had the same issue.

Any ideas on what to do to fix this???  - i have put Penrite Transoil 140 in the gearbox, so quite a thick oil...but don't think that is the issue.  I suspect i now have to drop the gearbox and have a look inside to see what's wrong - how easy is this to do with the engine still on the car??

[simonandjuliet]

Have you driven the car much before changing to 140 - or has it always run with that in the box ?

I use 90 in my gearbox , so can't vouch for the 140, but if you decide to remove it,  I usually take the engine and box out together because I have found it a fiddle to separate them on the car - be interested to see what others say, but the whole unit comes out very quickly and with fewer frustrations to my mind

[DavidHill]

Hi Simon,

I think that has what has been in the gearbox...but i have not driven it much at all, as only got it back on the road last December and have been struggling with front suspension and then the rear suspension since then....so i estimate i have only done around 10-13 miles total...

is it worth draining and putting in a thinner oil do you think?

ref taking out the whole engine and gearbox together, that is how it went in with the radiator too, but the radiator was a pain to get in, so we removed that and fitted it separately, but that was a pain too...so ideally i would just drop the box on its own...but is that very difficult too?

[Raahauge]

My experience is that gear selection issues are often due to a problem with the clutch. You do not say whether the engine was running when you were stationary and unable to select, it would be helpful to know. My view is that oil viscosity is unlikely to be the issue.
I have done it several times and found it easier to install and remove the engine and box as one unit including the rad.
Keep at it, the rewards are great.

[Sliding Pillar]

I agree, it's much easier to take the engine gearbox and rad out as one unit.
I used 140 grade g/box oil in mine, I found it gave a better gear change.

[Sliding Pillar]

Have you checked that the clamp bolt on the clutch pivot arm hasn't come loose?

[DavidHill]

Unfortunately the issue is there when the engine is not running, with the car stationary...so i assume not a clutch issue? 

Is the problem with just dropping the gearbox getting it sufficiently far back to disengage from the clutch before dropping it, and then putting it back in engaged with the clutch?

[Sliding Pillar]

David, it's a long time since I last worked on an Aprilia gearbox, but I think it's almost impossible to withdrawal the rod that the clutch release arm is fixed to with the box in the car and you can't split the gearbox from the engine with the clutch release arm Insitu. (Is that correct Simon?)
If you can't engage the gears properly, have the gear selector forks become misaligned? Very easy to do if someone has removed the gear stick by undoing the grub screws on the side of the ball joint at the base of the gear lever. The gear lever should only be removed by unscrewing it, leaving the ball joint in place.

[DavidHill]

Yes it may be miss aligned gear selector forks...but i have not touched the gearlever attachment, merely driven the car for a few miles...so something has broken i think.  I tried the box again this am after leaving it to cool overnight.  Stationary with engine off on first go I had 1st and second and reverse easily slotting in. but 3rd and 4th not able to slot in.  Then after a few goes i lost the ability to get 1st as well...so can only consistently get the lever into 2nd and reverse positions.

I do now recall Peter Harding struggling to get the gearbox onto the clutch/back of the engine when he put them together as a unit before i refitted it...so i agree, the whole lot has to come out.  Question is if i do find broken parts etc in the box are they available?

[Andrew Cox]

I’m quite sure it is necessary to remove both engine and gearbox together. It is an issue that has been discussed before and my recollection is that the consensus is that it would be all but impossible to remove the gearbox separately. I use a Penrite synthetic 75 or 80 grade oil in the Aprilia, Noel Macwhirter found using this solved his gear changing issues.
Before you pull out the engine and gearbox you might consider first draining the gearbox oil to check for debris.
If all seems OK on that front, you could remove the clutch inspection plate from the bottom of the gearbox, loosen all the clutch spring retaining bolts ( you will need to rotate the engine by hand), make sure the friction plate is central and then retension the bolts. The last bit is a long shot but it does seem very odd that the gearbox was hard to fit.

[williamcorke]

Mr 'all but impossible' here.

Coincidentally, yesterday I removed the gearbox from my S1 Aprilia with the engine still in the engine bay. It was pretty tricky but I couldn't figure out how to get the engine and 'box out in one - couldn't see how to get a sufficient angle on the unit (front pointing up) to allow the front lower end of the sump to clear the front axle and bodywork by it, and top rear of the engine to clear the bulkhead. I managed to remove the vertical clutch actuating shaft by unclamping it top and bottom and extracting it from the top ('box tilted down at the rear). This gave enough movement on the actuating arm to allow it to free from the clutch release on the flywheel.

Much cussing involved.

[ColinMarr]

Stretching my memory back 50 or so years (sometimes easier than two weeks!), I recall problems with clutch and gearbox that required removal of the box, and I remember it was relatively easy to get the box out with the engine in-situ. And this was working single-handed and long before I had a trolley-jack. Yes, you have to undo the clamp-bolt on the clutch release (and jiggle it a bit) and remove the rear coupling, but the box should come out and back in again without trouble. Having said that, sorry I can’t help with your original problem.

[Andrew Cox]

I am impressed that it is possible to remove the gearbox separately from the engine. I would imagine you would need to remove at least the exhaust and the rear engine mounts to attain enough angle the remove the gearbox?
An alternative method of removing both engine and gearbox is to use a four post hoist and a mobile table.
After you have detached everything from the engine and box except the engine mounts, you lower the car until the sump is touching the table, remove the mounts and then lift the car up leaving the engine and box on the table.
I did this six months ago but you need to strip a lot more stuff off the engine ( exhaust manifold etc) and the only real advantage is you don’t risk scratching the paint in the engine bay.

[simonandjuliet]

A couple of additional comments, I always take the radiator off and on an S2 car, I usually take the rocker cover off as well because the extra bulkhead shroud leaves even less room for tipping the engine back towards the bulkhead - this would also give more room on an S1

If you can, try and unthread the gearlever from the 'knuckle' because if you remove the whole lever you risk moving the selectors - this is especially important for refitting !

If nothing is seized, the whole thing takes 1-2 hrs

[simonandjuliet]

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