Possible gearbox problem

[mezzle992]

Hi, I’m hoping someone can point me in a direction of what my issue is.


When coming off and going on to the throttle I get a metallic knock from the front end. It doesn’t do it going over bumps, no vibration when driving etc. its more pronounced when letting off the throttle than going on. Almost like some rotational play somewhere. I can get the same noise by rocking the car by hand when it’s in gear. I get no clicking from the driveshafts on full lock either way, I know it’s not suspension components as they are all new and torqued down properly. I can get a click sound (sounds like it’s from the gearbox) when I jack the car up and rock the front wheels rotationally.


It’s a preface k11 with a cg13 engine on a 1.0 box. I don’t know much about driveline and transmission so any help would be appreciated.

 

[John_D]

Hi, I’m hoping someone can point me in a direction of what my issue is.


When coming off and going on to the throttle I get a metallic knock from the front end. It doesn’t do it going over bumps, no vibration when driving etc. its more pronounced when letting off the throttle than going on. Almost like some rotational play somewhere. I can get the same noise by rocking the car by hand when it’s in gear. I get no clicking from the driveshafts on full lock either way, I know it’s not suspension components as they are all new and torqued down properly. I can get a click sound (sounds like it’s from the gearbox) when I jack the car up and rock the front wheels rotationally.


It’s a preface k11 with a cg13 engine on a 1.0 box. I don’t know much about driveline and transmission so any help would be appreciated.

Check the front wheel bolt tightness. I had the same problem a few months ago on my Micra and the O/S front wheel bolts had slackened off, almost imperceptibly, just enough to allow rotational movement..........

 

[fuzzy-hair-man]

Engine mounts allowing excess movement? Clonking the gearbox, shifter, exhaust etc

 

[mezzle992]

I have checked all these things there seems to be a lot of play in the nearside driveshaft where it goes into the gearbox, maybe worn splines or missing circlip, its been out recently

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[pollyp]

assuming you've checked all the engine mounts are firm & bolted tight, all suspension bolts are tight, no broken suspension arms, offside driveshaft & differential bearing feels solid.
if the nearside inner CV shaft wiggles alot and both driveshafts measure the same diameter, it could be a worn bore in the differential casing that supports the inner shaft.

In my case I recently had to machine a special thin collar for my LSD to stop it rattling at high speed.
https://www.micra.org.uk/threads/pollymobiles-rebuild.35251/page-155#post-747745

you can either replace the diff or its far easier to just replace the whole gearbox.

 

[mezzle992]

I get the feeling its the latter of the 2, its getting a 1.3 gearbox at some point this year (will be pulling the old one apart just because im inquisitive ) my trouble is i have a facelift 1.0 box that wont fit my 1.3 engine and a preface 1.3 box that wont fit my engine, the bellhousings dont line up

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[pollyp]

I get the feeling its the latter of the 2, its getting a 1.3 gearbox at some point this year (will be pulling the old one apart just because im inquisitive ) my trouble is i have a facelift 1.0 box that wont fit my 1.3 engine and a preface 1.3 box that wont fit my engine, the bellhousings dont line up

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all the CG13 bellhousing should fit the CG13 blocks. u check the dowels & bolts are in the right place? remember that preface 1.3 & 1.0 box have different driveshaft, flywheel & clutch size.

 

[mezzle992]

I have all the shafts etc, they line up on most the bolts (my engine is a 94 auto block) except the bottom 2 which on my engine are 2 brackets, i have a 97 1.0 box on there at the moment. Will try to get a pic of the types im dealing with

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[mezzle992]

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[mezzle992]

The second picture is what i have fitted and the first is the bolt pattern of the other gearboxes i have

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