Question for all those with 3.9 final drive
#1
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
Question for all those with 3.9 final drive
Yeah... so i thought waiting for three weeks for the proper shims and parts would make this work flawlessly, but...
the rear end of my car is now singing like an opera star... the pitch is independent of engine rpm, but is based on vehicle speed... the higher the speed, the higher the pitch...
it's about 5-10x louder than my tilton, and it's really ****ing annoying
after talking to Z1 Auto on AIM, he seems to think it's driveline backlash due to improper shimming.
just wondering what exactly causes this, where exactly the noise is coming from, and how i can explain it to this guy so that he can do it properly.
thanks in advance!
the rear end of my car is now singing like an opera star... the pitch is independent of engine rpm, but is based on vehicle speed... the higher the speed, the higher the pitch...
it's about 5-10x louder than my tilton, and it's really ****ing annoying
after talking to Z1 Auto on AIM, he seems to think it's driveline backlash due to improper shimming.
just wondering what exactly causes this, where exactly the noise is coming from, and how i can explain it to this guy so that he can do it properly.
thanks in advance!
#2
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
update:
after talking w/ Z1 some more, it comes from improper toe mesh of the gear/pinion and improper distance between the gear and pinion
car is back at the shop getting tuned up a bit... we'll see what they say
but, if you can deal with the noise (which i can't... the tilton has become normal, but this is above and beyond)... this thing hauls *** now!
after talking w/ Z1 some more, it comes from improper toe mesh of the gear/pinion and improper distance between the gear and pinion
car is back at the shop getting tuned up a bit... we'll see what they say
but, if you can deal with the noise (which i can't... the tilton has become normal, but this is above and beyond)... this thing hauls *** now!
#3
Registered User
iTrader: (6)
Re: Question for all those with 3.9 final drive
Originally posted by Machupo
Yeah... so i thought waiting for three weeks for the proper shims and parts would make this work flawlessly, but...
the rear end of my car is now singing like an opera star... the pitch is independent of engine rpm, but is based on vehicle speed... the higher the speed, the higher the pitch...
it's about 5-10x louder than my tilton, and it's really ****ing annoying
after talking to Z1 Auto on AIM, he seems to think it's driveline backlash due to improper shimming.
just wondering what exactly causes this, where exactly the noise is coming from, and how i can explain it to this guy so that he can do it properly.
thanks in advance!
Yeah... so i thought waiting for three weeks for the proper shims and parts would make this work flawlessly, but...
the rear end of my car is now singing like an opera star... the pitch is independent of engine rpm, but is based on vehicle speed... the higher the speed, the higher the pitch...
it's about 5-10x louder than my tilton, and it's really ****ing annoying
after talking to Z1 Auto on AIM, he seems to think it's driveline backlash due to improper shimming.
just wondering what exactly causes this, where exactly the noise is coming from, and how i can explain it to this guy so that he can do it properly.
thanks in advance!
If its making that much noise, I would not drive it anymore other than to take it to another driveline shop.
A competent driveline mechanic would not have to have that explained to him. The 3.9 should make a little more noise than stock, but nothing more than having to turn the stereo up a notch.
Last edited by zillinois; 02-22-2005 at 01:40 PM.
#4
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
Re: Re: Question for all those with 3.9 final drive
Originally posted by zillinois
The noise comes from gear alignment which is too far out of spec. There are two gears that intermesh. A ring gear and a pinion gear and they have to be very closely aligned. Lash is how much play there is between the gears. Lash can play an important part of gear noise. Besides the lash, there is also a pattern between the gears where they touch. When you turn the pinion gear it makes a pattern on the ring gear and that pattern is determined by the lash, pinion preload and pinion gear depth and location. You want the shape and location of that pattern to be very precisely centered on the teeth. Those all have to be adjusted to very close specifications in order for the gear to function properly. If you have a lot of noise, your gears are not aligned properly and you are generating a lot of extra heat and wear.
If its making that much noise, I would not drive it anymore other than to take it to another driveline shop.
A competent driveline mechanic would not have to have that explained to him. The 3.9 should make a little more noise than stock, but nothing more than having to turn the stereo up a notch.
The noise comes from gear alignment which is too far out of spec. There are two gears that intermesh. A ring gear and a pinion gear and they have to be very closely aligned. Lash is how much play there is between the gears. Lash can play an important part of gear noise. Besides the lash, there is also a pattern between the gears where they touch. When you turn the pinion gear it makes a pattern on the ring gear and that pattern is determined by the lash, pinion preload and pinion gear depth and location. You want the shape and location of that pattern to be very precisely centered on the teeth. Those all have to be adjusted to very close specifications in order for the gear to function properly. If you have a lot of noise, your gears are not aligned properly and you are generating a lot of extra heat and wear.
If its making that much noise, I would not drive it anymore other than to take it to another driveline shop.
A competent driveline mechanic would not have to have that explained to him. The 3.9 should make a little more noise than stock, but nothing more than having to turn the stereo up a notch.
can't wait to ditch the 400 pound singing lady in the trunk and really rip into this baby
#5
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
oh, and even the cusco RS pops and bings a bit, but i imagine that's just break-in and will subside once i get her out to do figure 8's and swap out the diff fluid
thanks again,
-nick
thanks again,
-nick
#6
Registered User
iTrader: (1)
We have the sims here in stock so if you find out what you need exactly let me know. I would love to offer a shim kit but there are about 20 different sizes and they are about $12.50 each so to offer a complete kit with 1 of each of the shims would be a bit pricey....and there is a posiblity of need 2 ofthe same size. Every housing is different.
#7
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by dwnshift
We have the sims here in stock so if you find out what you need exactly let me know. I would love to offer a shim kit but there are about 20 different sizes and they are about $12.50 each so to offer a complete kit with 1 of each of the shims would be a bit pricey....and there is a posiblity of need 2 ofthe same size. Every housing is different.
We have the sims here in stock so if you find out what you need exactly let me know. I would love to offer a shim kit but there are about 20 different sizes and they are about $12.50 each so to offer a complete kit with 1 of each of the shims would be a bit pricey....and there is a posiblity of need 2 ofthe same size. Every housing is different.
can i have the guy give you a call if he's having trouble? i really want this to go well and not destroy the rear end of my car
Trending Topics
#8
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
back in the shop getting re-shimmed
dwnshift: they may start sourcing their shims through you, since you've got a better selection / availability than anyone in north america
thanks!
-nick
dwnshift: they may start sourcing their shims through you, since you've got a better selection / availability than anyone in north america
thanks!
-nick
#10
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by dwnshift
I had ordered a couple of all the sizes a while ago. It took a some time to get them in.
I had ordered a couple of all the sizes a while ago. It took a some time to get them in.
#11
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
ok, got the car back again...
it's still making a ton of noise (albeit less than before)... i'm going to take it up to Tidewater Z tomorrow and have them listen to it and see what they can do... luckily i've got a crapload of shims, so if it needs to be redone, they can do it.
another Q... would changing fluids make the sound go away? thanks!
-nick
it's still making a ton of noise (albeit less than before)... i'm going to take it up to Tidewater Z tomorrow and have them listen to it and see what they can do... luckily i've got a crapload of shims, so if it needs to be redone, they can do it.
another Q... would changing fluids make the sound go away? thanks!
-nick
#12
Registered User
iTrader: (1)
Drive her up here and well get it straight.
Sounds like something isnt right.....should not be hearing it.
The backlash can be set a little loose which will really help rear end temps and will ahve a little bit of noise but nothing annoying.......but if is making that much nosie....its not set up correct.
Cheers
BJ@350EVO.com
Sounds like something isnt right.....should not be hearing it.
The backlash can be set a little loose which will really help rear end temps and will ahve a little bit of noise but nothing annoying.......but if is making that much nosie....its not set up correct.
Cheers
BJ@350EVO.com
#13
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by dwnshift
Drive her up here and well get it straight.
Sounds like something isnt right.....should not be hearing it.
The backlash can be set a little loose which will really help rear end temps and will ahve a little bit of noise but nothing annoying.......but if is making that much nosie....its not set up correct.
Cheers
BJ@350EVO.com
Drive her up here and well get it straight.
Sounds like something isnt right.....should not be hearing it.
The backlash can be set a little loose which will really help rear end temps and will ahve a little bit of noise but nothing annoying.......but if is making that much nosie....its not set up correct.
Cheers
BJ@350EVO.com
believe me, i've learned my lesson about not having you do the driveline stuff
#14
Registered User
Thread Starter
iTrader: (6)
Join Date: Aug 2004
Location: Eltmann, Franconia
Posts: 1,676
Likes: 0
Received 0 Likes
on
0 Posts
BJ, you've got a PM -- i'm having the stock stuff put back in, at least they can do that, i'm going to ship everything to you -- if you don't mind
thanks,
-nick
thanks,
-nick
Thread
Thread Starter
Forum
Replies
Last Post
bcoffee20
Zs & Gs For Sale
5
11-19-2015 06:39 PM
Bodyboarder81
Forced Induction
13
09-21-2015 06:23 AM