Slipping Out Of Third

[scbond 15 1 Cars]

Ok, so just replaced the gearbox after the diff blew on the old one. All has gone well though getting a nice gear change took a lot of faffing about adjusting the cable just so. I have noticed a few things though...the engine/exhaust sound a bit different (could just be me), it feels differently driving in most of the gears (again, could be me or that my old box was shot yet I was used to that) and the engine, despite not touching anything else, started idling higher.

 

The main issue though is that the lever occasionally slips out of third gear. All others are fine...did have difficulty for a bit until I got the clutch cable set right, but third is still popping out. it does seem like it doesn't go all the way in but I'm pushing it as far as it goes.

 

After setting the cable and still having the issue I checked the linkages. All uprated previously. During the gearbox change I tightened up the mount for the main rod, which eliminated the floppy gear stick, then backed it off a bit to give a small amount of play. The quadrant on the off-side does seem to get very close to the main rod mount where it bends does under the ball joint but doesn't seem to be stopping anything.

 

Any ideas?

[welshpug 1,661]

you shouldnt need to leave any bolts loose, which one do

you mean?

 

if it's not staying in gear it could be the spring clip and a worn out synchro.

[scbond 15 1 Cars]

I was thinking synchro but hoping not. Is there one dedicated synchro ring for third? What spring clip do you mean?

 

The bolt was the one for the main linkage mount. Accessible inside the subframe. This was quite loose and when I tightened it up the gear lever went very stiff, but I'm pretty used to it being floppy by now so slackened it off haha.

 

If it is the synchro then the seller of the box is paying to have it removed because there's no way I'm getting back under there!

 

Another thing worth mentioning is that there seems to be a bit of slip at the moment, but I had that down to a brand new pressure plate on the almost new Luk clutch disc. My pedal used to be set pretty much level to the brake pedal but to get it right now I had to have it set about 1cm higher.

Edited October 18, 2015 by scbond

[scbond 15 1 Cars]

Could it be an engine mount? From memory it does seem to happen when cornering or accelerating...last time it happened was on a fairly large roundabout.

 

I did remove the lower mount from the engine to remove the gearbox (easier than shifting the intermediate shaft from the bearing) and it did look as though the subframe side could be tighter, but I'd need to have a better look. I guess the gearbox mount could be better too.

[welshpug 1,661]

if the ball pivot is tight you need to lubricate it not leave the nut loose!

 

there is a spring clip on the synchro hub, this may be broken/missing though in this case afaik it should still stay in gear unless it has been crunched into gear for a prolonged period of time and damaged the teeth on the gear hub.

 

if you are having linkage issues they can be highlighted by worn mounts, though I would expect it to happen in 5th too

Edited October 18, 2015 by welshpug

[scbond 15 1 Cars]

Ok, and does third have it's own syncro? Would've thought first, third and fifth would be sharing, in which case syncro failure would affect them too?

[welshpug 1,661]

each gear bar reverse has its own synchro, however the units for 1-2 and 3-4 are paired assemblies so cannot be swapped individually.

[scbond 15 1 Cars]

Ok, thanks. Will keep an eye on it over the next few days. If it is the gearbox is it possible to sawp the gear housing over easily to the current bell housing?

[scbond 15 1 Cars]

After getting the clutch cable as it was before all this happened, and then some sensible, normal and a bit of quick accelerating it seems to be fine again. Seems like the clutch cable was just badly adjusted?

 

One thing I really don't get is that the engine was idling very high (around 1,800) once warm since changing the gearbox. I didn't touch anything that should affect the idle speed so don't get why this would be the case? I've just done a setup on the idle speed and with the air screw in I had to wind the throttle stop screw out a fair bit before it even dropped at all, let alone to 600 RPM. Seems fine now but a big adjustment was needed when it was setup perfectly before...so what could've change it?

[Anthony 1,003]

Have you disturbed the wiring plug on the SAD at all? If that's unplugged then the SAD takes ages to close and it'll idle near 2k rpm, and that's located just above the gearbox.

 

The clutch cable adjustment shouldn't make it pop out of gear, but I guess the engine mounts might do if there was enough movement - does the gear level move excessively as you come on and off power?

[scbond 15 1 Cars]

Have you disturbed the wiring plug on the SAD at all? If that's unplugged then the SAD takes ages to close and it'll idle near 2k rpm, and that's located just above the gearbox.

 

The clutch cable adjustment shouldn't make it pop out of gear, but I guess the engine mounts might do if there was enough movement - does the gear level move excessively as you come on and off power?

 

Left the SAD plugged in and undid the plate the housing above it is fixed to in order to improve access so not that.

 

Removed the dizzy, though I set that back exactly as it was.

 

Do you mean movement in the gear lever as I come on and off the clutch? Not really. the last it slipped out was going fairly quickly around a roundabout...didn't even notice until I pressed the throttle and got revs and nothing else.

 

When I first took it out after changing the box I had tightened the linkage support as described above and changes were very tight (almost too tight) and the cable was badly adjusted so the biting point was well off. It now bites at the right height, bit of vibration but dying down as I expected, and it hasn't slipped out of third since those first few times, mainly when going hard right.

 

There is a bit of rotational movement on the mounts but it has always been like that while owning it and never slipping out of gear.

 

If it was the synchro it would be grinding going into the gear, no? Starting to think fairly confidently that it isn't that.