Wobbly stick and Whoompy rear end

[jont]

Hey guys

Just s quicky!

It's a 180Sx SR20DET. The gearbox is ok, no major issues, but the shifter stick is very floppy, I've not had a stick like this before. So if you move the stick into neutral, it almost flops to the side as there is so little resistance to keep it up. It makes the transmission feel weak an feeble, even though mechanically it is OK. Any idea why it does this? I guess part of the shifter stick assembly has worn? It won't be the gearbox itself I imagine.


Separate to that, at some point I need to address the Whoomp Whoomp sound from the rear end. Between 40-55mph. Frequency linked to speed. Not hugely loud. No other symptoms. Do we know which items can Whoomp Whoomp? I guess:
- diff internals (although I can't see why they would Whoomp)
- wheels & tyres for some reason
- brakes possibly?

- I don't think driveshafts could do this
- I don't think prop could do this as it is spinning much faster that the sound

Thanks

Jon

[ANDY black s13]

the nylon bush on the ball end of the gear stick could be worn or broken/cracked,and /or one of the gear stick side springs has broken
if the gear stick and the 6 bolt plate is removed you will soon see,

regards the other fault,is the car on stock sub frame bushes,diff mounts,suspension arms/rods ?
as anything that mounts diff or sub frame more solid/firmer will transmit more noise into the car

[jont]

Cheers Andy I can do the shifter check, so I'll get that done.

Regards the rear end:
- stock 90k miles subframe bushes with those locking ring inserts that I put in.
- stock diff mounts
- Apex non-ball jointed adjustable arms
- stock bottom arms & ball joints
- the diff is actually the wrong one for the car, I lifted it from a UK S13, so I thought it would be the same, but it turned out that it pushed the prop 20mm+ into the gearbox which caused a conflict between prop and gearbox rear.

I guess it could be any of those things above. As long as it's only a sound problem, then I guess it's not too important anyway.

I could try running the car in the air to see if I could make the sound happen I guess.

Thanks

[autosri]

Will most likely be the diff internals making the noise I'd guess

[green_rs13]

does it whomp whomp on acceleration or just deceleration?

the side to side on the gearshifter is controlled by the springs/plungers that are found behind the two large bolts either side of the rear of the box. they remind me of Frankenstein's neck bolts. fairly easy thing to fix, just watch out for ball bearings popping out.

[Sean-B]

Sounds like the driveline is being loaded up excessively by the diff / prop issue

[shikari chaos]

I too have a strange drone/pulse noise that changes with road speed. Does it sound like it's coming from one particular side or only occurs on left or right bends? Another thought is wheel bearing..

[ANDY black s13]

Sounds like the driveline is being loaded up excessively by the diff / prop issue

it's always hard to diagnose a sound when you can't hear it,but same as Sean above^
I'm not liking the prop is 20mm further in the g/box either, could try undo center bearing and check if the prop can slide further into g/box
or if it can't it's bottomed out on the output splines and you need a shorter prop rear half
abs and non abs 13's have longer short props , abs diff nose is longer/prop is shorter, possible car was N/A had open diff OE ?
180sx in s14 section with a 13 diff has confused me a tad,

[jont]

Sorry guys I forgot to check my thread. To answer some:

it's always hard to diagnose a sound when you can't hear it,but same as Sean above^
I'm not liking the prop is 20mm further in the g/box either, could try undo center bearing and check if the prop can slide further into g/box
or if it can't it's bottomed out on the output splines and you need a shorter prop rear half
abs and non abs 13's have longer short props , abs diff nose is longer/prop is shorter, possible car was N/A had open diff OE ?
180sx in s14 section with a 13 diff has confused me a tad,

Hey Andy. OK this explains the fitment perfectly. My car is Non-ABS from factory, the diff that I installed was ABS, hence it being longer. I used my non-ABS prop. Well the mechanic did not know any of this or didn't tell me. By the time I have driven home, the front of the prop had actual eaten the whole rear of the gearbox housing in approx. 20-25mm and the steel glove that sits on the end of the gearbox has completely gone. So the prop actually fits fairly well now, and despite my gearbox being shortened and the glove missing, it all fits fairly well with no rubbing. I re-mounted the centre donut bearing 20mm further towards the gearbox. I forget exactly how I did this, was a few years ago, but it sits and feels comfy, without any un-comfortable looking stretch in the rubber, like there was before. So that's that mystery solved.

I too have a strange drone/pulse noise that changes with road speed. Does it sound like it's coming from one particular side or only occurs on left or right bends? Another thought is wheel bearing..

I have only noticed it on straights, approx. 40-55mph. Unsure if it has a left/right bias, nothing obvious.

Sounds like the driveline is being loaded up excessively by the diff / prop issue

Yes but I can't find anything that is un-happy in how it sits. Do we know if the ABS diff is wider than the non-ABS diff? Then it could be loading the driveshafts wrong. Could the Driveshafts be on the wrong way round maybe?

does it whomp whomp on acceleration or just deceleration?

the side to side on the gearshifter is controlled by the springs/plungers that are found behind the two large bolts either side of the rear of the box. they remind me of Frankenstein's neck bolts. fairly easy thing to fix, just watch out for ball bearings popping out.

I only notice it at cruise and de-acc. Though I am pretty sure it does it on acc, but the exhaust is very loud so can't be 100%

Interesting, can one access these bolts from under the car without any major modification? Thanks

Will most likely be the diff internals making the noise I'd guess

Yes it could be that, and if so, not a major issue, would just be nice to know.

I had a look down there today and the driveshaft rubber boots are not held on with any clips, and I see grease leaking from one inner joint. What a strange thing to find? Any idea where I'd find clips to secure these boots? Thanks

[green_rs13]

probably can get to them with the box fitted, worst case undo the gearbox mount bolts. just take them out and compare the spring lengths/ stretch/shim with a bit of coke can to whatever you choose.

[jont]

Yup that sounds good.

[jont]

Here are some vids from today:


1) https://www.youtube.com/watch?v=aafMjnCwFCI 5th Gear Idle

Some banging coming from drivetrain, unsure if diff or gbox. Does anyone else get this at idle? I assume it's just some looseness in the drivetrain internals?

2) https://www.youtube.com/watch?v=nAa-suFQPFw 40mph 5th gear low throttle.

I can not get it to make the whoomping sound that it makes when driving. Interestingly it doesn't make the banging sound that it makes on idle.

I don't think this tells anything useful, but any comments anyway?

THanks