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Stiff gearchange

Posted: 07 Sep 2013, 16:05
by CJH
The gearchange in my van is not consistent - sometimes it's very smooth and easy, but sometimes it's very stiff. In particular, it goes through patches where it seems as though it's difficult to get OUT of gear, but in the course of the same journey it seems to fix itself so that everything is smooth and easy again. I'm assuming some part of the linkage is worn - any ideas what bits I should check/adjust?

What I've already replaced:
- The gearbox has just had a bit of a refurb - it needed a new 3rd gear syncro hub, and it had new bearings, seals, gaskets etc as part of the rebuild. The syncro rings themselves were not replaced but were fine apparently.

- The clutch and the release bearing were in good shape so were not replaced.

- While my box was being refitted the linkage also had a new one of these:
Image

...and a new one of these:
Image

So what's next? One of these perhaps:
Image

All advice gratefully received.

Re: Stiff gearchange

Posted: 09 Sep 2013, 06:50
by CJH
*bump* - hoping to catch the eye of the returning Busfest folks

Re: Stiff gearchange

Posted: 24 Oct 2013, 14:07
by CJH
I narrowed down the symptoms to just when everything gets hot, and it feels as though it might be the clutch dragging a bit. So I fitted a new clutch slave cylinder, having read somewhere that another forum member had an issue with a slave cylinder that became lazy when hot. I mentioned this in the What did you do to your T25 today? thread, but so as not to pollute that thread with technical discussion I've moved the discussion here.

HarryMann asked:
HarryMann wrote:Did you 'dress' the clutch fork arms like it suggests in the wiki.
Removing any flats...

It was my local garage that did the gearbox fitting for me, and they're not VW specialists so I doubt very much that they did. Does it sound like this could be the problem?

I've taken the van for quite a long run now, and the odd thing is that it's better after fitting the new slave cylinder, but not completely fixed. I can't really figure that out. I'm wondering now if it was down to partially refreshing the hydraulic fluid. I did enough bleeding to get the air out of the system (which essentially meant just filling the new cylinder up), but I didn't flush out the whole line. I wonder if the fluid is so old that it's become contaminated, and becomes a little bit compressible when hot. Having a bit of fresh fluid in the line might mean that it's now slightly less compressible. Does that seem feasible?

I'm also planning to refresh the gearbox oil, as it's now a few hundred miles since the rebuild, although this problem was there the first time I went on a long run. I have no idea if this is the case, but is it possible that the wrong grade of gearbox oil could cause this symptom?

Re: Stiff gearchange

Posted: 24 Oct 2013, 16:45
by Ralf85
I had what might be a similar problem. See below, including Aidan's comments.

https://club8090.co.uk/forum/viewtopic.php?f=37&t=123906" onclick="window.open(this.href);return false;

Good luck!
:ok

Re: Stiff gearchange

Posted: 24 Oct 2013, 17:10
by CJH
Ralf85 wrote:I had what might be a similar problem. See below, including Aidan's comments.

https://club8090.co.uk/forum/viewtopic.php?f=37&t=123906" onclick="window.open(this.href);return false;

Good luck!
:ok

Thanks Ralf

Yes, I saw your thread earlier, thanks. The ball on the end of my release arm is still there - it was quite dry and corroded so I greased it up when I fitted the new slave cylinder.

CJH wrote:I wonder if the fluid is so old that it's become contaminated, and becomes a little bit compressible when hot. Having a bit of fresh fluid in the line might mean that it's now slightly less compressible. Does that seem feasible?

This is my new favourite theory. I've just finished flushing through the hydraulic fluid and what came out wasn't pretty - very dark with visible silt in it. I suspect this means I should be looking at the reservoir, the master cylinder and the pipework too, and I should probably be doing the same to the brake circuit too. After this weekend I've got no more trips away planned, so I'm planning a bit of an overhaul of the braking system anyway. Fingers crossed that the gearchange is improved after this evening's flush.

Re: Stiff gearchange

Posted: 24 Oct 2013, 17:12
by Aidan
did you fit a new spigot bearing when the box was refitted ?
often worse when cold is typical of failing spigot bearing

Re: Stiff gearchange

Posted: 24 Oct 2013, 17:22
by CJH
Aidan wrote:did you fit a new spigot bearing when the box was refitted ?
often worse when cold is typical of failing spigot bearing

No, my garage said it looked like the clutch and bearing weren't very old, so we didn't change them. Did you mean to write it that way round? My problem is that the gearchange is nice and slick when cold, but it gets difficult to push the stick out of gear when everything's hot.

Re: Stiff gearchange

Posted: 24 Oct 2013, 19:44
by ermie571
hi - the spigot bearing is not related to the clutch parts.

Its in the hole where the gearbox input shaft locates into the engine through the flywheel. Its a needle bearing and supports the input shaft.

Its a bugger to get out unless you have a bearing puller.

When it dies you will know all about it....cos you will have some god-awful grinding noises...then you won't be able to engage or dis-engage the gears when the engine is running!

do a search on here for spigot bearing

I didn't know stiff gear change when cold was a symptom of failing bearing... Mine just collapsed. big time. In Rush hour on a major crossroads! I wasn't particularly popular as i was stuck in third so wasn't going anywhere!

Em
xx

Re: Stiff gearchange

Posted: 24 Oct 2013, 19:56
by max and caddy
Just spotted this thread...I have a similar issue with my pick up...the majority of the parts in question are new or refurbished...but it does tend to hold onto gears and needs a yank to disengage at times, it's not terrible but its not silky smooth either...it's as if the selector rod is sticky and gets glued into the bushes...needing a bit of a tug to unstick it but then it's fine again until its been in a gear for a wee while.

Im fairly sure ts not the clutch and is either the linkage or the gearbox itself...maybe the syncro hub binds on the gear after having load put into it..? There is still a bush in the center of the linkage I have not even looked at never mind greased so maybe that's dry and all it is but I'm not so sure..

Not a huge problem but a bit annoying that my budget gearbox on my aaz van is silky, but the very expensive Spangley weddle geared, nonexpense spared almost box has a poorer shift..

The forks on the bottom of my lever ain't perfect either but would that cause a sticky lever? I'm 99% sure the clutch has no issues...but then again it is a Valeo one!

Re: Stiff gearchange

Posted: 24 Oct 2013, 20:00
by itchyfeet
ermie571 wrote: Its a bugger to get out unless you have a bearing puller.


Em
xx


M8 rawlbolt does the trick :D

https://club8090.co.uk/wiki/Pe ... ft_bearing" onclick="window.open(this.href);return false;

Re: Stiff gearchange

Posted: 24 Oct 2013, 20:10
by CJH
ermie571 wrote:hi - the spigot bearing is not related to the clutch parts.

Its in the hole where the gearbox input shaft locates into the engine through the flywheel. Its a needle bearing and supports the input shaft.

Ah, thanks for the explanation Em. Well I hope it's not that then! I'm still not sure whether Aidan meant it's worse when cold or hot. My gearchange is lovely when the van is cold. I changed a few parts when the repaired gearbox was put back in, and it snicks into gear really nicely. It's only a problem when everything is hot. I'm being very careful not to force anything - if I take my time and let the revs die a bit then it changes without force on the second or third attempt. In my mind I can imagine that if it IS the clutch dragging a bit then it'll be easier when the engine revs have died away, hence it being easier if take my time.

I've checked over the receipts that came with the van. It's apparently an 'Elite' engine that was fitted 12 years ago, but it's only done 19,000 miles since then. The clutch was replaced at the same time, so I doubt it's had another clutch since then. Hopefully a new spigot bearing was part of the deal, but who knows. The brake fluid was done at the same time, but judging from the state of the clutch fluid I flushed out tonight that may well be the last time it was done!

max and caddy wrote:Just spotted this thread...I have a similar issue with my pick up...the majority of the parts in question are new or refurbished...but it does tend to hold onto gears and needs a yank to disengage at times, it's not terrible but its not silky smooth either...it's as if the selector rod is sticky and gets glued into the bushes...needing a bit of a tug to unstick it but then it's fine again until its been in a gear for a wee while.

That sounds just like mine. Is yours OK when the van's cold?

Re: Stiff gearchange

Posted: 24 Oct 2013, 20:14
by max and caddy
Yes, I normally only notice it after driving in one gear say along a slower road, cold I expect a bit of blocking due to the oil etc but it shouldn't cause the gears to hang..

Re: Stiff gearchange

Posted: 24 Oct 2013, 20:20
by CJH
max and caddy wrote:Yes, I normally only notice it after driving in one gear say along a slower road, cold I expect a bit of locking due to the oil etc but it shouldn't cause the gears to hang..

Maybe it's just wishful thinking on my part, but it definitely fits the symptoms of a dragging clutch. I think. Imagine what it would feel like if you tried to change gear without dipping the clutch. Now, what's causing that dragging clutch is another question. In my case changing the slave cylinder improved things a bit, but didn't cure it. After flushing the fluid this evening I took it out to the shops - not really far enough to test it, but there was absolutely no sign of the problem.

I hope I haven't just jinxed it. It's going on a long trip tomorrow, so I'll know for sure.

Re: Stiff gearchange

Posted: 24 Oct 2013, 20:41
by Ian Hulley
Sticky and hard to get out of gear when hot ? Is this particularly between certain gears ?

Ian.

Re: Stiff gearchange

Posted: 24 Oct 2013, 20:42
by CJH
Ian Hulley wrote:Sticky and hard to get out of gear when hot ? Is this particularly between certain gears ?

Ian.

No - all gears.