Rear End whine, new parts - tech said it's ok?
11-26-2010, 04:38 PM
#1
1st Gear Member
Thread Starter
Join Date: Oct 2010
Location: Texas
Posts: 60
Rear End whine, new parts - tech said it's ok?
OK so I just recently installed 4.10 gears and a Posi Trak Differential.
After the install the tech walked me out and told me there was a whine when you get to a certain RPM and that was because the 4.10 gears were so big and where they fit inside my 4.0 its going to rub and make that whine - and there is nothing I can do about it.
Well driving it home, sure enough the whine hit and it was annoying as hell.
I don't have the dual exhauset installed yet and assume the whine will be drowned out a bit after I get it, but this can't be good for the rear end, can it?
The pro shop I use is very popular and has a great track record - apparantly people from all over the world go there.
I trust these guys to know what they are doing. But after reading a bit on the forums, what I've got going on isn't normal.
Any advice out there on what I should do?
Do I ignore it like the tech says and just get the exhaust installed and hope it's drowned out by the rumble?
Thanks for any advice - please note I can live with it if I have too -it's just really annoying -
The improvement the gears and diff made for my pony are amazing and wouldn't trade it for the world.
Tam
After the install the tech walked me out and told me there was a whine when you get to a certain RPM and that was because the 4.10 gears were so big and where they fit inside my 4.0 its going to rub and make that whine - and there is nothing I can do about it.
Well driving it home, sure enough the whine hit and it was annoying as hell.
I don't have the dual exhauset installed yet and assume the whine will be drowned out a bit after I get it, but this can't be good for the rear end, can it?
The pro shop I use is very popular and has a great track record - apparantly people from all over the world go there.
I trust these guys to know what they are doing. But after reading a bit on the forums, what I've got going on isn't normal.
Any advice out there on what I should do?
Do I ignore it like the tech says and just get the exhaust installed and hope it's drowned out by the rumble?
Thanks for any advice - please note I can live with it if I have too -it's just really annoying -
The improvement the gears and diff made for my pony are amazing and wouldn't trade it for the world.
Tam
11-26-2010, 05:17 PM
#2
3rd Gear Member
Join Date: Jul 2009
Location: Garner NC
Posts: 765
In all honesty take it back, there should be no whine in the rear end, I did the same exact mod and they told me something similar, that the gears will settle in and the whine will go away, more than likely the lashing gap is to big, if your gears are motive, the lashing should be between .008 - .010 and that is an email response I got from motive. What happened to me, I got my gears put in, 9 months later, the shims fell out on the passenger side and I had to get that repaired. So don't take no for answer.
11-26-2010, 11:14 PM
#3
4th Gear Member
Join Date: Mar 2007
Location: tennessee
Posts: 1,227
sorry to hear about that. I would say something is wrong.
I installed 4.10s myself in my f150, and installed 3.73's in my mustang and if the backlash or pinion isnt shimmed properly it will whine. It whines because something isnt set right. I have heard folks say that certain brands of gears whine, i cant comment on that, i have always installed ford racing gears in my cars and not one second of whining...
I installed 4.10s myself in my f150, and installed 3.73's in my mustang and if the backlash or pinion isnt shimmed properly it will whine. It whines because something isnt set right. I have heard folks say that certain brands of gears whine, i cant comment on that, i have always installed ford racing gears in my cars and not one second of whining...
11-27-2010, 12:00 AM
#4
2nd Gear Member
Join Date: Nov 2008
Location: texas
Posts: 199
OK so I just recently installed 4.10 gears and a Posi Trak Differential.
After the install the tech walked me out and told me there was a whine when you get to a certain RPM and that was because the 4.10 gears were so big and where they fit inside my 4.0 its going to rub and make that whine - and there is nothing I can do about it.
Well driving it home, sure enough the whine hit and it was annoying as hell.
I don't have the dual exhauset installed yet and assume the whine will be drowned out a bit after I get it, but this can't be good for the rear end, can it?
The pro shop I use is very popular and has a great track record - apparantly people from all over the world go there.
I trust these guys to know what they are doing. But after reading a bit on the forums, what I've got going on isn't normal.
Any advice out there on what I should do?
Do I ignore it like the tech says and just get the exhaust installed and hope it's drowned out by the rumble?
Thanks for any advice - please note I can live with it if I have too -it's just really annoying -
The improvement the gears and diff made for my pony are amazing and wouldn't trade it for the world.
Tam
After the install the tech walked me out and told me there was a whine when you get to a certain RPM and that was because the 4.10 gears were so big and where they fit inside my 4.0 its going to rub and make that whine - and there is nothing I can do about it.
Well driving it home, sure enough the whine hit and it was annoying as hell.
I don't have the dual exhauset installed yet and assume the whine will be drowned out a bit after I get it, but this can't be good for the rear end, can it?
The pro shop I use is very popular and has a great track record - apparantly people from all over the world go there.
I trust these guys to know what they are doing. But after reading a bit on the forums, what I've got going on isn't normal.
Any advice out there on what I should do?
Do I ignore it like the tech says and just get the exhaust installed and hope it's drowned out by the rumble?
Thanks for any advice - please note I can live with it if I have too -it's just really annoying -
The improvement the gears and diff made for my pony are amazing and wouldn't trade it for the world.
Tam
11-27-2010, 01:15 PM
#7
5th Gear Member
Join Date: May 2007
Location: Central Texas
Posts: 2,388
Yep, indeed. THERE SHOULD BE NO WHINE from a properly installed set of gears.
There is no "rubbing" anywhere, there can't be.
What happens, as mentioned, is the backlash is not adjusted properly. This affects the distance that the ring gear makes contact with the pinion gear. Get it going fast enough at the right speeds, the metal parts create harmonics and that's what you hear. It'll be really bad at certain speeds, and may show up at several different speeds.
There are specific specifications for setting the backlash properly. With these Ford rear ends, you use "shims", like big round and very thin flat washers, and those are used between the differential carrier and the housing to move the differential closer to farther away from the pinion gear, this adjusting the backlash. With the close tolerance (.008-.012), it takes a some work to try to get it right (more trial and error), hence more time for the tech to do it right. In a shop, this can result in an attitude of "just get it done and out the door". More than likely, a tech will just use the shims that are there from the factory, since those were used to set the proper backlash for the factory gears. Well, with 4.10's and most other sizes, this cannot work, as the gear teeth and everything are different dimensions, so different shims must be used to set the backlash properly. Also what can happen is the differential itself is not properly cleaned and the new 4.10 ring gear is not fully seated on the carrier, and as such, is slightly tilted. That's even worse, and would make for a lot of whine.
Improper backlash will result in premature gear wear as well, so it's not something to "just live with". Done right, there should be little to no whine at all.
I've done a few sets of gears, and on my current set of 373's, they do whine a little, as I expected they would, right at 40 mph; but that's because I intentionally left the backlash a little out of spec on the large end (for racing purposes).
Now, there are a lot of people around with some whine at some speeds, especially with 4.10 gears. However, any tech that told you what you posted is full of crap!!!
There is no "rubbing" anywhere, there can't be.
What happens, as mentioned, is the backlash is not adjusted properly. This affects the distance that the ring gear makes contact with the pinion gear. Get it going fast enough at the right speeds, the metal parts create harmonics and that's what you hear. It'll be really bad at certain speeds, and may show up at several different speeds.
There are specific specifications for setting the backlash properly. With these Ford rear ends, you use "shims", like big round and very thin flat washers, and those are used between the differential carrier and the housing to move the differential closer to farther away from the pinion gear, this adjusting the backlash. With the close tolerance (.008-.012), it takes a some work to try to get it right (more trial and error), hence more time for the tech to do it right. In a shop, this can result in an attitude of "just get it done and out the door". More than likely, a tech will just use the shims that are there from the factory, since those were used to set the proper backlash for the factory gears. Well, with 4.10's and most other sizes, this cannot work, as the gear teeth and everything are different dimensions, so different shims must be used to set the backlash properly. Also what can happen is the differential itself is not properly cleaned and the new 4.10 ring gear is not fully seated on the carrier, and as such, is slightly tilted. That's even worse, and would make for a lot of whine.
Improper backlash will result in premature gear wear as well, so it's not something to "just live with". Done right, there should be little to no whine at all.
I've done a few sets of gears, and on my current set of 373's, they do whine a little, as I expected they would, right at 40 mph; but that's because I intentionally left the backlash a little out of spec on the large end (for racing purposes).
Now, there are a lot of people around with some whine at some speeds, especially with 4.10 gears. However, any tech that told you what you posted is full of crap!!!
11-30-2010, 10:14 AM
#10
1st Gear Member
Thread Starter
Join Date: Oct 2010
Location: Texas
Posts: 60
Thank you all for the info - I will go back and see what they can do about it - if they cannot or give me excuses I'll post up the name but I want to give them an opportunity to fix this before I burn them.
Tam
Tam