Here's the deal, 2006 G35 6MT, with f/r hotchkis sways and other non-suspension performance mods. Rear sway set to middle hole. Front was most tight but I adjusted it back one after about a year. Car will be tracked on occasion and I have done some hard cornering and stopping (stoptech bbk).

Anyway, when accelerating hard in 1st and 2nd (sometimes 3rd) the rear gets real loose. My perception is that the rear end lowers in the right rear and the whole back end sort of slides left and there is an obvious loss of traction until it works itself out. Sometimes the VDC kicks on, sometimes not. It's very repeatable. Much more pronounced if I'm turning the steering wheel at the time. It's not regular tire slippage. Definitely feels like something not right.

I'm ready to get this fixed and not sure what all to get. I have visually inspected everything and nothing looks bad. No strange noises. From my searching seems endlinks would be good.. maybe bushings (which ones?), compression rods??

Anyone know what this is and what I need? I just don't feel like it's safe to accelerate hard the way it is anymore.

 

That's weird when I mounted my sways I had them set middle front, middle rear (stillen) and the car handles good. Maybe you having set up the front harder that the rear affected your feeling of the car. Try Hard on the back and soft the front. IF you are having this problem accelerating on a straight line then there is something wrong with your car.

 

There is definitely something wrong, just not sure what. The other strange thing I forgot to mention is the alignment seems to be fine... which surprises me after it does what it does. The handling seems good for cornering (I guess, I've been taking it easy) but acceleration gets wild. I was thinking maybe the VLSD but I'm pretty stumped. Been living with it for over a year thinking it was maybe normal but I'm convinced it's not and it's time to do something.

 

Are the tires worn evenly? How about the shocks?

 

I had an alignment 10 months ago when I got new rear tires and they seem to be wearing normal. Car drives straight cruising without touching the steering wheel. I haven't tried a hard acceleration from cruising without touching the wheel but my guess it would veer off to the right if I hit it with enough torque. It definitely starts pointing right as the rear slides left from hard accelerations at lower speeds but quickly gets back to normal when the torque settles down.

I've searched a lot on this issue from time to time over the past several months without luck. When it first started happening I thought maybe the right wheel was spinning inside the tire because it would feel like one wheel was going and the other side wasn't... very strange feeling. Passengers have also noticed it and were like... wtf is that? Feels kind of like doing a burn out but no sound and haven't noticed rubber on the road behind me when it happens. Another thought is something is wrong with the VDC and not any suspension parts. Only happens in high torque situations, which is rather easy in the first 3 gears. I generally avoid it now for fear something will just break.

I don't think it's a shock. Suspension feels very tight otherwise. Just fishing for ideas before I drop money on things that may not help.

 

When was the last time the rear diff fluid was changed?

 

About 3 months ago (2300 miles) with Mobil 1 75w90. Also did the front MTF with Nissan OEM MT fluid, brake fluid with Motul rbf600, PS Fluid, Clutch fluid, Oil, etc.. hehe. I take excellent care of the G and probably over-maintain but as an (occasional) track car in the making this issue is unacceptable.

 

check your rear differential mount bushings as well. If they're leaking, that could cause the diff to articulate under load and cause the car to "walk"

 

thats what she said

 

Could be bushings... I hope it's not those rear diff ones... looks like a major PITA to change. Seems to be lots of talk of this on the Z forums. SPL Solid bushings seem to be the business. Gawd I hope it's something easier to fix.. not really what I'd describe as wheel hop... more like one wheel feels like it going to break off. Seriously.

Hey Trix! My thoughts exactly. Good to see another DFW G... I need to get to a meet and meet n stuff... yep.

 

you has PM

 

Well... I checked out the 3 rear diff bushings and they all look good. The rear one looks a bit saggy buy not busted. I checked all bushings and they seem fine. Will probably replace them all at some point but for now I don't think it's the problem. Endlinks look normal. Control arms check... rear sway bolts check.. still stumped. I'll take the G out tomorrow and stomp it with the VDC off and see what happens. So strange.

 

Well, for the record I'll post my experience and maybe this will help someone... as best I can figure it was a tire pressure issue. My RR tire was at 29psi and my LR was at 31. Now I don't normally run that low so it had lost some pressure since I last put air. I filled both rears to 35.5 and try as I might with VDC on and off I could not recreate the issue I had. In fact, my traction was better than I've ever experienced! Seems to be good on the Falken FK-452's on 19" wheels.

Still, I see some serious weakness in the rearmost rear diff bushing and have decided to upgrade all the bushings for good measure.