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Gearbox Help Please


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#1 Its a min

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Posted 05 August 2018 - 10:52 PM

Hi all.

 

I've got a bit of a strange problem with my A+ series gearbox.

 

To give some background, I recently replaced all bearings, layshaft and new genuine rover baulk rings. All seemed ok whilst the gearbox was seperated from the block albeit the gears being a little tight to turn. I put this down to the new baulk rings.

 

Connected it all up and now, it feels like it's in gear when you try to push the car when it's in neutral and clutch released. If the clutch is depressed, it seems better but it's hit and miss as to what gears I can engage until I move the car i.e. it goes into 1st, 3rd, 4th and reverse but not in 2nd. If I release the clutch and try pushing it whilst in neutral, there is some resistance (as though it's in gear) but will then allow me to select 1st, 2nd, 4th and reverse but not 3rd and so on.

 

With the engine running, gearbox in neutral and clutch pedal pressed down, seems to run fine apart from not being able to engage all gears as above. If I release the clutch, still in neutral, there is some resistance resulting in idle speed drop and the engine cuts out unless I keep the revs up.

 

Stuck it into 1st and tried driving and although it jolted to start with, it ran ok after a short while. Almost as though the baulk rings had bedded in. However,when I tried to change up to second, I got gear crunch and refusal to go into gear. If I try driving it in reverse, I have to up the revs and it jolts/kangaroos although this has also eased and is starting to run smoother but not much. In addition to this, there seems to be a knocking noise when I try to drive it.

 

Any help/advice/pointers into what the problem could be will be much appreciated as i don't want to drive her on the belief it is just the baulk rings needing to bed in.

 

Thanks all.


Edited by Its a min, 05 August 2018 - 10:54 PM.


#2 Retroman

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Posted 06 August 2018 - 12:14 AM

Ok It doesn't sound good, can't say for sure what it is as it has quite a few symtoms

 

Its obviously tight if you struggle pushing it in neutral, and its stalling bringing the clutch up in neutral.

 

New baulk rings should not be causing so much friction nor should new bearings.

 

What type of bearings did you use..? RHP, SKF ? or  'others'

 

Hate to say it but I think it will have to come back out for a diagnostic strip.

 

Do you know what the end float / clearance was on the primary and idler gears...?



#3 Magneto

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Posted 06 August 2018 - 02:44 AM

Sounds to me like it's trying to be in 2 gears at once, like you didn't get all the detents in place or the linkage isn't right. Did you remember to put the small ball and spring back under the right side diff cover?



#4 Moke Spider

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Posted 06 August 2018 - 03:22 AM

What gearbox casing do you have?



#5 harrythehat

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Posted 06 August 2018 - 06:19 AM

had a similar problem with Alice she had been sitting around for a few years after a rebuild

couldn't get third gear on changing up the box, go to reverse first, come out and it would go up the 123 4 change a ok.

 

try it again and the same thing. wont go in third . go to reverse and she goes up and down box fine.

 

my thought was the shaft that allows movement between the gates was stiff and use would bring it back into order.. (soz don't know technical names)

 

Jacked her up on blocks run the engine up added some slick 50 she loosened of a tad after an hour of gear changes more moving the gate between reverse and the main box than gear changes

next day still a bit stiff did the same she loosened of a bit more after lesser changes

Third day she was going in and out ok enough to say all good

 

shes gone to her new owner now, no gearbox probs glad to say



#6 unburntfuelinthemorning

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Posted 06 August 2018 - 07:48 AM

The gears should have turned freely with the gearbox off.  I think you'll be taking it out again as Retroman saith.  Sorry



#7 OzOAP

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Posted 06 August 2018 - 07:52 AM

Loads of issues with 'grabbing' baulk rings recently. There does seem to be a lot of **** ones regardless if you go for pattern, supposedly genuine or competition.

#8 Allrounder

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Posted 06 August 2018 - 09:59 AM

Might not be much help now but when ever I take on a job of this nature I photograph and document everything. Make diagnoses these sort of problems easier

Wonder if it's possible, did you put the 1-2 gear synchro on the correct way!

#9 Retroman

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Posted 06 August 2018 - 10:14 AM



Loads of issues with 'grabbing' baulk rings recently. There does seem to be a lot of **** ones regardless if you go for pattern, supposedly genuine or competition.

 

  Does make you wonder why...I can't come up with any logical reason[s], its almost like they need lapping on individually

 

I do wonder if its down to some worn tooling when they are made. Not sure of the exact process, but with heat involved too anything is possible.



#10 big john

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Posted 06 August 2018 - 11:38 AM

Recently rebuilt a gearbox for a friend and when reassembled would barely turn by hand when in neutral (out of the car, laying on the garage floor.) If put in any gear it spun easily. Kept thinking it would loosen up when installed, but in the end took it apart to see what was wrong. Two of the brand new syncro rings were thicker than the originals (.010-.020".) I'd unknowingly installed them together on the 3-4 hub and they bound up. I had two older, but good condition rings in my spares so I put them in and everything works fine now. Sounds like yours may have to come back apart.



#11 Retroman

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Posted 06 August 2018 - 11:54 AM

Thicker in which way ?



#12 Its a min

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Posted 06 August 2018 - 05:29 PM

Ok It doesn't sound good, can't say for sure what it is as it has quite a few symtoms

 

Its obviously tight if you struggle pushing it in neutral, and its stalling bringing the clutch up in neutral.

 

New baulk rings should not be causing so much friction nor should new bearings.

 

What type of bearings did you use..? RHP, SKF ? or  'others'

 

Hate to say it but I think it will have to come back out for a diagnostic strip.

 

Do you know what the end float / clearance was on the primary and idler gears...?

Hi Retroman,

 

I think, to much dismay, you and the others are right and it all needs to come out again. On the positive side, this is the first time I've done a gearbox, thanks to all the threads on TMF, Guessworks & Mini Mania videos, so it's all good learning.

 

I did notice quite a big gap (approx 4-5mm) between one of the baulk rings and gear but assumed this was due to them being new rings as the old ones were still the original rings from 1989 when i bought the car new.

 

As for bearings, I believe they were SKF an some in unmarked boxes (minispares). Followed the video on Mini Mania when I set the endfloat so unless something moved, it should be within tolerance but guess I'll find out when I strip it again.



#13 Its a min

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Posted 06 August 2018 - 05:32 PM

Loads of issues with 'grabbing' baulk rings recently. There does seem to be a lot of **** ones regardless if you go for pattern, supposedly genuine or competition.

Hi OzOAP,

 

Can you, or anyone else, recommend decent rings?

 

Cheers.



#14 Its a min

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Posted 06 August 2018 - 05:44 PM

had a similar problem with Alice she had been sitting around for a few years after a rebuild

couldn't get third gear on changing up the box, go to reverse first, come out and it would go up the 123 4 change a ok.

 

try it again and the same thing. wont go in third . go to reverse and she goes up and down box fine.

 

my thought was the shaft that allows movement between the gates was stiff and use would bring it back into order.. (soz don't know technical names)

 

Jacked her up on blocks run the engine up added some slick 50 she loosened of a tad after an hour of gear changes more moving the gate between reverse and the main box than gear changes

next day still a bit stiff did the same she loosened of a bit more after lesser changes

Third day she was going in and out ok enough to say all good

 

shes gone to her new owner now, no gearbox probs glad to say

 

Hi harrythehat,

 

I'd love to think it was that simple but i wouldn't want to risk doing any damage etc.

 

The gears should have turned freely with the gearbox off.  I think you'll be taking it out again as Retroman saith.  Sorry

 

I had a feeling I would...but all good experience I guess.

 

Might not be much help now but when ever I take on a job of this nature I photograph and document everything. Make diagnoses these sort of problems easier

Wonder if it's possible, did you put the 1-2 gear synchro on the correct way!

 

I took photos before I dismantled it all so I had a reference to work from. Also checked against various other images and it all looked ok but guess I'll find out. Lol.

 

Recently rebuilt a gearbox for a friend and when reassembled would barely turn by hand when in neutral (out of the car, laying on the garage floor.) If put in any gear it spun easily. Kept thinking it would loosen up when installed, but in the end took it apart to see what was wrong. Two of the brand new syncro rings were thicker than the originals (.010-.020".) I'd unknowingly installed them together on the 3-4 hub and they bound up. I had two older, but good condition rings in my spares so I put them in and everything works fine now. Sounds like yours may have to come back apart.

 

Hi big john, I've still got the old rings and one or two of them still looked to be reasonable condition (not that I really know what that looks like) but still had a fair gap between the ring and gear so may experiment when it all comes out.

 

Thanks for everyones comments so far.



#15 OzOAP

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Posted 06 August 2018 - 06:26 PM

[/quote]
Hi OzOAP,
 
Can you, or anyone else, recommend decent rings?
 
Cheers.[/quote]

I am now getting customers to supply baulk rings so its their choice.
If I supply them, and there is a problem, it's down to me to fix it.
I don't want to have to take engine out, strip and rebuild gearbox because of a ******* baulk ring after 500 miles.




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