Rebuilt gearbox stiff in 1st & 2nd gears. Any ideas why?

[David]

Hi everyone,

Just a quick question for someone in the know.

I rebuilt my BX gearbox back in June, with all new bearings & seals. The car has done around 1000 miles since.

It’s nice & quiet, & in 5th, 4th & 3rd, it slides in & out of gear smoothly & easily, but 1st & 2nd are a different story. It’s stiff to get it in both gears. If I rev match the engine to the gearbox, then it’s a little easier, but it still feels ‘notchy’ when it engages. It’s most noticeable when I’m slowing down &, unless I’m stopped, I can’t get it in 1st gear. When the car is stopped, it’ll usually go straight in both gears, (or if the engine isn’t running & stopped), but sometimes still feels a bit tight. So, has anyone got any idea what could be causing it?

I checked the gear teeth on the gears themselves & on the synchromesh & there was a bit of wear on 1st gear, but not so much that I’d think would cause any issues. 2nd didn’t look worn. All the selector rods in the gearbox seemed to work fine & all the rods on the car are free & in good condition.

The only thing that I suspect it could be is either the selector fork, and/or synchro for 1st & 2nd gears, seems as it’s the same part that does both gears, but they didn’t seem to be in bad condition (although I could’ve missed something on the synchro as I’m not an expert on them).

So, is there something that I’m overlooking or does anyone know what it might be?

Thanks in advance.

[xantia_v6]

Are you sure that you put correct GL4 oil in the gearbox?

[Jugostran]

Hi everyone,

Just a quick question for someone in the know.

I rebuilt my BX gearbox back in June, with all new bearings & seals. The car has done around 1000 miles since.

It’s nice & quiet, & in 5th, 4th & 3rd, it slides in & out of gear smoothly & easily, but 1st & 2nd are a different story. It’s stiff to get it in both gears. If I rev match the engine to the gearbox, then it’s a little easier, but it still feels ‘notchy’ when it engages. It’s most noticeable when I’m slowing down &, unless I’m stopped, I can’t get it in 1st gear. When the car is stopped, it’ll usually go straight in both gears, (or if the engine isn’t running & stopped), but sometimes still feels a bit tight. So, has anyone got any idea what could be causing it?

I checked the gear teeth on the gears themselves & on the synchromesh & there was a bit of wear on 1st gear, but not so much that I’d think would cause any issues. 2nd didn’t look worn. All the selector rods in the gearbox seemed to work fine & all the rods on the car are free & in good condition.

The only thing that I suspect it could be is either the selector fork, and/or synchro for 1st & 2nd gears, seems as it’s the same part that does both gears, but they didn’t seem to be in bad condition (although I could’ve missed something on the synchro as I’m not an expert on them).

So, is there something that I’m overlooking or does anyone know what it might be?

Thanks in advance.

One thing I have to ask - since I have a similar problem - have you replaced the right side (driver's side in the UK) top engine mount? Because changing it without installing spacers from a 205 will result in the engine and gearbox not sitting correctly/moving about too much, which will cause the aforementioned problems. Essentially in this situation you're pushing the gearbox and engine when shifting into gears.

[David]

Thanks for the replies!

Apologies for not replying sooner, I simply haven't had time!

To be honest, I can't remember what oil I put into it. I said at the parts supplier that the gearbox needed a specific oil, (as I've read it on here before, but I couldn't remember exactly what it said), & they said that it'd be fine for this gearbox. I also filled the transfer box with the same oil, so I hope it's the correct one! I'll check the tub when I can, as I've got some left.

Surely, if it was the oil, wouldn't it be stiff in all of the gears though? I went for a drive over to Yorkshire today, & its 'tight' getting into both gears, although 1st is more tight, whereas 2nd is more 'notchy'. At one point, it just went straight into 1st & I didn't realise it'd actually gone into gear; it just slid in like it should. It doesn't make a difference if the car is cold or hot, it behaves exactly the same.

Again, after the drive today, it slid into all of the other gears fine, even when the car was cold (I had to change between 4th & 3rd many times over the moors) so I'm more inclined to think it's something to do with either the synchromesh or the selector fork for 1st & 2nd, otherwise surely everything else would be stiff too?

I have replaced all of the engine mounts on the car. I had to put some washers between the engine mount on the drivers side, as it didn't sit correctly beforehand. The engine & gearbox are firm & cannot move.

Has anyone got any more suggestions before I essentially condemn the secondary shaft in the gearbox? If need be, I'll try another 1st & 2nd gear.

Any further input would be greatly appreciated. Of course, I'll check the oil container & report back.

[Jaba]

This may not be relevant but many years ago I had to change the first motion shaft in my Maxi. But afterwards I found one or two of the gears quite difficult to get into. As it was ok before my intervention I dismantled the box again and found that I had put a synchromesh ring in the wrong way round - which obviously would stuff smooth gearchanges.
This may or may not help you but good luck with sorting it out anyway David.

[David]

Thanks for the reply!

The synchro is definitely in the right way; the one for 1st & 2nd also has reverse on it, so, the car wouldn’t go into reverse if it was the wrong way. It physically looks different on both sides too & as I took a picture before dismantling it, & ensured it went back the same way.

I still haven’t checked the oil tub yet.

I had a quick mess with it yesterday; with the car stopped, engine running & clutch held down, it goes into all of the gears fine, even reverse, but 1st & 2nd are just tighter than the rest. When the car is moving, they’re even harder. (This was cold, I didn’t drive it apart from moving it up the driveway).

Oh, just another quick question: there’s a tiny flat bearing that goes between the 1st gear cog & the output cog (to the final drive) on the secondary shaft , but it doesn’t appear to do much, besides creating a gap between the said cogs. When the shaft was held vertically (before reassembly), this bearing appeared noisy, but in general use, it doesn’t seem to be ran on or used, so, could this be causing any issues? My thought is no, because the gears themselves run on floating shells & pressurised gear oil, & the synchro & 2nd gear are nowhere near this bearing, so surely if it could cause a problem, then it’d just be 1st?

Any more ideas would be appreciated!

[David]

Alright, just a quick update on this; I believe it’s been fixed! I dismantled the gearbox again & I’ve replaced 1st & 2nd gears along with the synchromesh & the selector fork.

I think the issue was actually the synchromesh as there’s nothing that moves on 1st & 2nd gears themselves, & the fork looked ok too, unless it was sticking on the selector shaft. There was some wear on the teeth on the back of 1st, but it wasn’t that bad. 2nd was unworn, but I just changed everything as it’s such a pain to get to.

It’s still a little stiff in 1st gear, but nothing like it was; I can get it into 1st if the car is moving slowly now, whereas I couldn’t before. I’ve only done a 15 mile test drive, but it already seems a lot better!

I’ve still not looked at the oil container for the specifications though; I also reused the oil that was already in the gearbox because it’s not been in for long.

Thanks everyone for the input!

[jamescarruthers]

If you have rebuilt a gearbox you are more skilled than I but the mention of GL4 and sychro problems really screams out to me as on my other car love (Volvo 480, with a Renault gearbox) it is well known that GL5 oil claiming to be compatible with GL4 can mess up the bronze parts of the synchromeshes.

We stick to Elf NFP but a call to Opie Oils may also be good.

AFAIK GL4 is nicely compatible with yellow metals, GL5 less so-- some people say it eats it up, but that may be an exaggeration.