Bump After Letting Off Accelerator

[Brad13]

Hi guys, I seem to have a bit of a bump after letting off the accelerator in my 96 R33 GTST. I originally thought it was diff backlash so I've swapped the diff but it hasn't made any difference. I'm all out of ideas as to what it could be. Any suggestions?

[kingtube69]

Diff bushings?

[Brad13]

They seemed to be fine when I replaced the diff. It does it even with minimal acceleration, if anything it's a lot more noticeable then too

[Kinks]

what about the uni joint /CV joint in the driveshaft?

engine mounts?

[GTSBoy]

CV joint #1 likely villain. Also possibly centre bearing/CV in the tailshaft.

[Brad13]

I can feel it through the back of the seat, wouldn't think engine mounts would be the cause of that would they?

How difficult is the tail shaft bearing to replace?

[KiwiRS4T]

Get it up on stands - test with a bar - universals, centre bearing, gearbox and engine mounts.

[Brad13]

As soon as I get the chance I'll have a look. Was hoping it might be an easy fix

It wouldn't have anything to do with hicas at all would it? I wouldn't have thought it would caused this but I've heard of some people hearing a knock from the rear of their car with the Hicas unit still in.

[GTSBoy]

If the HICAS tie rod ends are rooted then they will allow the rear wheels to move back and forth to the extent of the slop in the joints, and could bang. But they'd be a little knock, not a big one.

[r32-25t]

It will be the mounts for the rest cradle

[BakemonoRicer]

+1 for broken subframe mounts.

[kingtube69]

It will be the mounts for the rest cradle

+1 for broken subframe mounts.

Any pics of the area you mean? I have the same sound and I'd like to know where to look. Do you mean the parts that bolt the subframe to the car (i.e where you would put the subframe collars?)

[Brad13]

Any pics of the area you mean? I have the same sound and I'd like to know where to look. Do you mean the parts that bolt the subframe to the car (i.e where you would put the subframe collars?)

Thanks guys, agreed that any pics of what I should be checking would be extremely helpful if possible. Just want to make sure I'm not looking for the wrong thing

[GTSBoy]

4 big arse studs hanging down from the chassis rails through 4 big arse bushes.

But I still reckon it will be a CV.

[kingtube69]

Yeah I just checked mine and they are all good. My CVs knock in the diff if I wiggle them... Im assuming thats not normal lol??

[Brad13]

Still haven't had a chance to get it up on stands to have a look around underneath. Will hopefully get a chance this weekend and I'll look over the CV's.

If they do knock is there a fix for them or will they have to be replaced altogether?

[Ben C34]

Replace.

[Brad13]

I've had the car up on stands and had a good look around. Cv's and subframe bolts all seem tight and solid. I'm now leaning towards this possibly being the tail shaft bearing as there's also a rattle/vibration I can hear at low revs or when under load going up a hill.

Does that sound plausible and would there be any way to go about checking it?

[GTSBoy]

True driveline bumps are usually able to be hunted for by grabbing two parts that should rotate together, hold one as still as you can, and rotate the other. If there is slop.....

[GRKGTR]

I've had the car up on stands and had a good look around. Cv's and subframe bolts all seem tight and solid. I'm now leaning towards this possibly being the tail shaft bearing as there's also a rattle/vibration I can hear at low revs or when under load going up a hill.

Does that sound plausible and would there be any way to go about checking it?

Hey Brad, Did you end up fixing this issue? I'm having the same problem