Help Tailshaft Hitting Tunnel

crossingover · 29-08-2006, 10:19 PM

hi guys ive just lowered the au with king springs and koni shocks sits very low looks a1 but under heavy acceleration in take off sounds like tailshaft is hitting tunnel under the console i have 19 inch wheels with 275 tyres on rear im wondering have i gone too low i want to keep it this height but not happy with noise also can it do damage car is extremely low but is not a daily driven hoping to put it in shows ill post pics in a few days SO ALL AU EXPERTS how do i fix this issue please help

Casper · 29-08-2006, 10:22 PM

by "under the console" do you mean where the transmission is? If its hitting there then its nothing to do with lowering. The lowering would cause it to hit further down the driveshaft tunnel closer to the back.
Possible broken mount for the transmission is my guess.

JC · 29-08-2006, 10:25 PM

Quote:

Originally Posted by crossingover

hi guys ive just lowered the au with king springs and koni shocks sits very low looks a1 but under heavy acceleration in take off sounds like tailshaft is hitting tunnel under the console i have 19 inch wheels with 275 tyres on rear im wondering have i gone too low i want to keep it this height but not happy with noise also can it do damage car is extremely low but is not a daily driven hoping to put it in shows ill post pics in a few days SO ALL AU EXPERTS how do i fix this issue please help

Only 2 things I can think of:

1. Take off slower
2. Raise the car back to a sensible height.

XR6-VCT-2000 · 30-08-2006, 09:29 AM

Sounds like maybe as you plant the foot the rear of the car is sinking , might be the top of the diff centre housing hitting the shell or the tailshaft hitting the top of the tunnel as you suggested ?? . I had the same sorta problem in my XE years ago ( although i never exactelly sorted it out to what was hitting ) , but the rear would sink a bit when i planted it .
I resolved the problem by putting extra heavy duty springs in the rear (at the time they were pedders red v8 extra heavy duty springs / made for if you had the extra weight of a gas tank in the back ). It didn't sit any higher than the spings i had in it before , but the new springs were 'very' thick coils and it sat hard as a rock on the road , made it alot more ridgid in the rear / had its pro's and con's .

How close are the coils to each other on your suspension in the rear ? If you have it really low there is possibilitys of the coils whacking on each other (re-tensioned original high springs been re-tentioned lower are prone to this cos the coils are so close to each other / too many coils for the height spring )/ fully compressed when you floor as the spring coils bottom out and whack as the rear of the car sinks , you could also maybe resolve the problem with harder shocks in the rear too if thats the problem. ??

just a few suggestions , good luck anyways , cheers .

crossingover · 30-08-2006, 11:11 AM

last night i rised car with stands to see where it is htting and yes was the closer end to the diff im in the process of ordering the lovells rear custom ,my current setup that i have was advised by a mechanic i think they call it 90/10 front touch higher and back down but those king springs i believe are only good for stock cars im not very happy with kings they are botteming out ive also got kyb shortened on the back got them from gt suspension alexandria so i think it comes down to springs.my car is at a sensible height but i am having traction issues i am mainly planning to run the car at calder i want it to jump off the line not spin off the line as said wont be a daily driver the au owes me nearly 25k in rebuilding so wont be out and about much until novelty wears off.