Help needed, knocking noise from rear

[Vasu]

Hi All,
I bought this Mx5 5 months ago, its a 2001 model, There is a hard knocking noise from the rear, this is heard mainly in slow speed while changing gear, also when you take the foot off the accelerator car does back and forth and after some research, decided that it was the shocks as the mechanic also noticed a leak in the shock so replaced them, the noise still there, I have been reading a number of forums with no joy, decided to ask for help. Could any one direct me towards identifying this issue.

Cheers

Vasu

[charged_rs]

on the rear there isnt that much to go wrong really

check the shock top mounts are tighted up with the 2 14mm nuts

check antiroll bar mounts - again 2 x 14mm nuts per side

check drop links for play

your springs might be knackered or broken - usually on mk1's the rear driver side spring cracks - havent seen it yet on a mk2

your shocks might be missing a rubber bushing as part of the top mount assembly.

[Fergus]

Whats your location ? I'm sure a member close by would offer to give it a quick inspection and locate the problem for you.
Or if your going on the run this weekend (or living along one of the routes from Cork/Dublin/Wexford etc etc) some of the guys could stop off and take a quick look at it.

Oh and beware of the majority of 'so-called' mechanics out there !

[Vasu]

Hi,
I have looked around the rear and have not been able to spot any issues, as mentioned I shall check shock mounts and the anti roll bar nuts. I live in Celbridge Co. Kildare; I will be delighted if any of you guys could have a look. If I'm cruising at any speed, there is no noise. If I am going slowly in a parking lot, the noise happens when I roll over a fairly sharp bump or hole. The slower I go-the more pronounced the sound is. The faster I go, the less it occurs

[Vasu]

Hi All,
After checking the shock mounts and the anti roll bars found nothing wrong.I decided to go to my mechanic and now he has concluded that the Gearbox needs to be rebuilt, I have no idea, of what spares will be needed for a gearbox rebuild.I believe my mechanic,if any of you have done any such could you please add your experience.

Cheers

Vasu

[charged_rs]

if he reckons its the gearbox....dead on

its rare the gearboxes give bother , unless the car has had 6 previous female owners lol ..only jokin


i would advise against rebuilding the box as it usually causes more problems

get a good second hand one and fit that instead.

i have a good used 6 speed for £250 here if you need / want it

[Steve]

As Paul said, its unusual for the gearbox to give a problem.
Hard to know the issue without hearing the knock, if its from the rear and your car is a 1.6, I'd also have him look at the differential while he has the car.
A worn diff can cause this :
"also when you take the foot off the accelerator car does back and forth"
and a worn/broken diff can sound like a broken gearbox.

If its a dull (rather than mettalic) knock, have the rear bushings checked too.

[sidewaysreilly]

check the cv joints.

[Vasu]

Hi all,
Thanks to all of you guys of the replies, I saved for the last three years to buy the car I like so much and I am not technically sound into repairs, getting a second hand gearbox sounds like a good idea, I will look at the CV joints tomorrow. If you guys have any meeting place around in the weekends please let me know I would like to meet yous.

Cheers

Vasu

[Vasu]

Hi,
My Mechanic is gone on holidays, so delayed. How would you check if the Differential is the cause. What to look for in case of CV joints. Could you let me know where you guys meet up in the weekends. Thanks for reading.

Cheers

Vasu

[andrew]

Hi Vasu,

I would get another mechanic to check that. The gearbox is not in the rear of the car. It could be one of the drive shafts or diff as previously suggested. Thet are much easier and quicker to fix than gearbox. I brought mine to C.A.R.S beside the leixlip resevoir on hewlet packard rd. They are old school polish lads, used to working on simple cars like MX5 and very reasonable. Best bet tho is to get a club member/mechanic to check it before you spend money.

[Vasu]

Hi All,
Thanks to all of you in helping me fix the issue. My mechanic got the gearbox reconditioned and now its running fine. I learnt that there are a few different types of gearboxes if anyone decides to change them. Thanks to Rob Maguire for his honest advice.

Cheers

Vasu

[dabofoppo]

where are you based in celbridge?
i'm in castle village

[franksm]

Grab the exhaust and give it a good shake, it's possible that it's knocking off something when you're changing gear etc.

Anyway, what I would do:

1. have a general look at tightness of bolts on prop shaft, driveshafts, etc
2. drain and refill the diff with fresh oil, ditto the gearbox (looking for slivers of metal in the old oil)
3. just drive the car till the problem gets worse