sizzlee gear box!

[stag76]

hi lads,on for a few ideas.

i have a mk1 mx5 1990,got the car with a worn clutch,and with use it started to slip.

she drove well,and as far as i know i had no bad noises on acceleracion or on over run.

got the clutch changed a week ago,all good,new clutch kit,and pilot bearing done.

have done around 100miles on car.

now to the problem,i start to drive,and after around 5miles i start to get a vibing/sizzling chatter from gear lever on overrun,and only on overrun.

it get worse as i drive on,or as things heat up,mostly in 3rd and 4th gear,not in 5th or lower gears.

strange thing is it only happens at speeds over 35mph.

over run in 3rd or 4th below 35mph no noise???

im lost?? i did have a 96 mx5 a year ago that had same problem,a buzzy sizzle,but it was all gears at any speed.

there is no bearing noise,or gear whering. im used to worn whering gearboxs in triumphs i have

oil level is good,new clutch,all is good

its a resanace kind of thing,you can feel a buzz or high pitch shake in the gear lever.

is it lack of oil in gear selector,a bush,??

any ideas, driving me a bit mad.

box is so smooth,and changes lovely,you can even rush it through the gears with no graunchs.

please help

jay

[peteh]

I'm not a mechanic or anything but that could be gearbox backlash?, remember reading something about it on the mx5 nutz forum, google "gearbox backlash problem" that should bring it up for you

[sidewaysreilly]

i would say that the gearbox has not been lined up properly with the PPF . There is a setting , did mine a while ago but forget the figure. Easy fix and wont take long. Just google mx5 gearbox allignment or something.

Some here will know it of the head.

[Steve]

oh yes, I remember doing this, you put a straight edge across the frame rails and measure the gap between it and the Power Plant Frame.
See here :

attachment.jpg

[stag76]

hi lads,just reading your posts there.

good stuff,its just a line up thing.


i dont mind the noise if im not doing damage.

ill look up the web and get the measurements and reajust it when i have timw (in the middle of a house move )

il let you know in the next while.

many thanks

jay

[stag76]

great steve has put up a diagram and measurements,brill .

thanks jay

[rhysmate]

sorry to bring up an old topic, but im having a gearbox issue.. when i put back my engine and drove it, i was getting a nasty vibration (loud and heavy) when the car was decelerating from around 3,500 revs. could it be caused by this? i thought it was the lay shaft or input shaft

[Steve]

maybe... or a u joint? Easier to check than the input.
Def not a heatshield or downpipe vibrating off the gearbox?

[rhysmate]

the downpipe was the standard downpipe then, so i doubt it.. it was a very strong vibration and only at certain revs so it could be a joint. it only started happening after the car was back together with a different engine but same gearbox as before... prop shaft and all were the same. one thing i did notice was the prop shaft doesnt sit all the way into the gearbox. ill take a picture tonight

[shaneh]

maybe the clutch wasnt lined up straight?
if you have to pull the gearbox onto the engine with the bolts then it isnt lined up.
theres a tool for doing it

[rhysmate]

i used an alignment tool and the gearbox slotted on fine. the clutch is spot on

[MX5Spares]

i have gearboxes for 75e if you do need one.and they do give some trouble as i have 2 other enquiries similar to yours --just waiting to confirm but looks like they will need gearbox also but check it out first !!!robert 086 8226506 swords

[rhysmate]

i have a second gearbox cheers though..