Hi all,

Just spent the last 2 hours going through the archives but to no avail, so any help would be much appreciated...

When cruising at low rpm and coming to a stop, my car starts to very violently shake/surge backwards then forwards and there is a tremendous banging noise which seems to eminate from under of the car - kinda where the end of the tranny is. The whole driveline feels sloppy but the shaking is almost unbearable.

After searching previous posts, i checked my engine mounts and replaced them and also ordered a ETB (RX7 store). This made a relatively decent improvement however it did not solve the problem completely. I read somewhere in the forum that it could be the diff shaking so i bought a diff brace. This morning, my diff brace arrived in the post and i installed it. After taking the car for a blat with the brace on, the banging is worse than ever and so extremely harsh that i had to stick the car in neutral when cruising in towards a red light. (The brace does wonders for fixing wheel hop BTW!!!)

My shifter is solid as a rock and so i don't think it's a cracked PPF. The knocking is definately coming from the centre of the car so I don't think it's bushings and the like.

Any help would be very much appreciated... and sorry for the long post!!!
Cheers!

 

wow. This sounds different. I guess all I can say is you need to check the PPF whether you think it is or not. It would make sense that its the PPF if it became more harsh when you put the diff brace on. Check that first and see if it is that or not, because it may be to your surprise a cracked PPF. That's what it sounds like to me.

 

thanks for the input, SpiritR. I'll check the PPF in the morning. But if the shifter doesn't have an sloppiness to it, could it still be the PPF? I thought that a tell-tale sigh of a cracked PPF is a sloppy shifter... or is this not necessarily so?

Do you think that by bracing the diff end of the PPF with the Diff Brace that it's amplified and isolated the clunking to the un-braced area, namely at the end of the tranny?

Thanks again!

 

what about diff bushings, the diff brace may have just amplified the effect of a bad dif bushing...im just speculating...


for the bucking during decel, make sure your tps is adjusted, et

 

thanks Damian. It could be the diff bushings BUT the sound and 'feeling' is definately coming from the centre of the car... i thought if it was bushings it'd possibly be the 'rear end' clunk so many people here have experienced. Still, won't hurt for me to check them out!

As far as the bucking goes, the TPS is spot-on ... but rather than a bucking, it's more like shaking a rag-doll by the shoulders! That's how intense it is!

Thanks again for the reply!

 

Maybe your exhaust is banging on something under the car with all this shaking? I'd seriously get the bucking worked out though.. Sounds as if you fix that, the noise will be gone too.

 

Dude, it's your clutch!! What your are discribing sounds exactly like the symptoms of a clutch not fully disengaging on deceleration.

 

I agree with trex. If you ride with people who are just learning to drive a stick and cant control the clutch that well, the car bucks and buckles a lot. Are you using the engine brake when coming to a stop (it sounds like you usually do because you said you had to put it in neutral when coming to a light) so it is probably something to do with the tranny or clutch not engaging properly or repetetive engagement/disengagement of the clutch.

 

Well this response is straight outta left-field! The clutch, you reckon? I hate my clutch! It's an OS Giken Twin Plate and it's the most unstreetable thing I've ever had... (it came with the car!)

Is there any way I can confirm that it is a clutch problem without dropping it out... i.e, are there any other symptoms i can expect from the clutch not disengaging properly? The car is sweet upon accel all the way to redline and decel down to about 2.5k rpm.

And... if it is the clutch... what's the fix? Ditch it and spring for a new one or is there a way to adjust it (aside from bleeding, which i'll do now).

Sorry... not to clutch/tranny savy, so any how-to or good info links would be much appreciated.... thanks for all the help everyone... and anymore suggestions would be welcomed...

 

There is an inspection door on the bell housing (held on by 2 screws). You'll need a flash light or a shop lamp when you get under the car to see into the inspection hole (use a ramp or a lift, or put the car on jack stands, don't just use a jack). 1st look at the back side of the inspection door. Look for any thing abnormal, ie. traces of metal shaving etc. Then look at the pressure plate as one of your buddies step on the clutch for you and see if it releases properly.
Oh, check your brake fluid quality and level as well. These are the simple checkes you can do before having to resort to major operations.

 

PPF