Can gears cause a vibration?
Thread Starter
6th Gear Member
Joined: Sep 2006
Posts: 11,278
From: Gainesville, FL
Can gears cause a vibration?
More specifically, can they cause a vibration at a specific rpm? I have a vibration at 3200rpms, but not at any other rpm. It is there with my stock driveshaft and my 1 piece driveshaft.
I'm getting 4.10's installed in 2 days and will be able to answer my own question, but I wanted to get a post in about it to see if anyone else has experienced a vibration at a specific rpm range?
I'm thinking it's the gears, stock pinion flange or transmission output flange. I've read that tires cause speed related vibrations so i've ruled them out.
I'm getting 4.10's installed in 2 days and will be able to answer my own question, but I wanted to get a post in about it to see if anyone else has experienced a vibration at a specific rpm range?
I'm thinking it's the gears, stock pinion flange or transmission output flange. I've read that tires cause speed related vibrations so i've ruled them out.
4th Gear Member
Joined: Oct 2005
Posts: 1,189
From:
RE: Can gears cause a vibration?
moose i had a small vibration and noise when i installed my gears at first. ford has a problem with the machining of the carrier on these cars. it causes the ring gear to rotate oblong which changes the backlash constantly and causes harmonics and vibrations to be transmitted throughout the vehicle. they had the same problem on the explorers which incidentally used the same 31 spline posi unit. they fix it at the factory by using a back cut ring gear and a special lapping process on the gears after install. oh and that stupid stock driveshaft has the CV joint at the differential to absorb all the vibrations from the axle assembly. the only way to fix it on my car was replacing the posi unit. i had tried 3 sets of gears and reset them multiple times trying to rid the car of the problem and i could change the speed at which it happened but never could make it go completely away until i installed an eaton posi unit.
Thread Starter
6th Gear Member
Joined: Sep 2006
Posts: 11,278
From: Gainesville, FL
RE: Can gears cause a vibration?
Thanks, that makes sense. I was hoping just changing the gears would get rid of it. I'm getting the gears installed on monday, but there's no way I can get a new differential by then.
I guess i'll have to change the diff down the road, but i've spent to much money in the past few days to do it now. Does the eaton you have use clutches? Everyone talks about the detroit true trac. how much is the eaton posi unit?
I guess i'll have to change the diff down the road, but i've spent to much money in the past few days to do it now. Does the eaton you have use clutches? Everyone talks about the detroit true trac. how much is the eaton posi unit?
ORIGINAL: spyder7724
moose i had a small vibration and noise when i installed my gears at first. ford has a problem with the machining of the carrier on these cars. it causes the ring gear to rotate oblong which changes the backlash constantly and causes harmonics and vibrations to be transmitted throughout the vehicle. they had the same problem on the explorers which incidentally used the same 31 spline posi unit. they fix it at the factory by using a back cut ring gear and a special lapping process on the gears after install. oh and that stupid stock driveshaft has the CV joint at the differential to absorb all the vibrations from the axle assembly. the only way to fix it on my car was replacing the posi unit. i had tried 3 sets of gears and reset them multiple times trying to rid the car of the problem and i could change the speed at which it happened but never could make it go completely away until i installed an eaton posi unit.
moose i had a small vibration and noise when i installed my gears at first. ford has a problem with the machining of the carrier on these cars. it causes the ring gear to rotate oblong which changes the backlash constantly and causes harmonics and vibrations to be transmitted throughout the vehicle. they had the same problem on the explorers which incidentally used the same 31 spline posi unit. they fix it at the factory by using a back cut ring gear and a special lapping process on the gears after install. oh and that stupid stock driveshaft has the CV joint at the differential to absorb all the vibrations from the axle assembly. the only way to fix it on my car was replacing the posi unit. i had tried 3 sets of gears and reset them multiple times trying to rid the car of the problem and i could change the speed at which it happened but never could make it go completely away until i installed an eaton posi unit.
4th Gear Member
Joined: Oct 2005
Posts: 1,189
From:
RE: Can gears cause a vibration?
to be honest i bought mine used for $100 so i have no idea which exact model it is but i'm pretty sure it did have clutches. it doesn't act like a true locker so it must have clutches instead of the ratchet mechanism.
2nd Gear Member
Joined: Mar 2007
Posts: 220
From:
RE: Can gears cause a vibration?
Moosestang/spyder7724:
I have also been having vibration problems witht he install of 4.10's in my 07 GT 5sp. Ifinally got it right on my third set 4.10 of gears. The first set were installed by a local SoCal speed shop, the second by a local Ford dealer and the third by a driveline shop. All three sets were FRPP 4.10's.The driveline shop finally got it right after about a dozen tries. They were as frustrated as me. Before I tried the driveline shop I also tried a PowerHouse aluminum driveshaft, but it only made the problem worse. I ended up using the stock driveshaft which gave me no problems with the original 3.55's.
Good Luck!
I have also been having vibration problems witht he install of 4.10's in my 07 GT 5sp. Ifinally got it right on my third set 4.10 of gears. The first set were installed by a local SoCal speed shop, the second by a local Ford dealer and the third by a driveline shop. All three sets were FRPP 4.10's.The driveline shop finally got it right after about a dozen tries. They were as frustrated as me. Before I tried the driveline shop I also tried a PowerHouse aluminum driveshaft, but it only made the problem worse. I ended up using the stock driveshaft which gave me no problems with the original 3.55's.
Good Luck!
Thread Starter
6th Gear Member
Joined: Sep 2006
Posts: 11,278
From: Gainesville, FL
RE: Can gears cause a vibration?
Was your vibration rpm related? I have a vibration at 3200rpm with the stock 3.55's and stock driveshaft. My 1 piece shaft makes it worse. I'm having 4.10's installed as we speak and hopefully the problem won't get worse.
You bought 3 different sets of gears? How bad was this vibration? enough to see in your rear view mirror?
You bought 3 different sets of gears? How bad was this vibration? enough to see in your rear view mirror?
ORIGINAL: dseid2
Moosestang/spyder7724:
I have also been having vibration problems witht he install of 4.10's in my 07 GT 5sp. Ifinally got it right on my third set 4.10 of gears. The first set were installed by a local SoCal speed shop, the second by a local Ford dealer and the third by a driveline shop. All three sets were FRPP 4.10's.The driveline shop finally got it right after about a dozen tries. They were as frustrated as me. Before I tried the driveline shop I also tried a PowerHouse aluminum driveshaft, but it only made the problem worse. I ended up using the stock driveshaft which gave me no problems with the original 3.55's.
Good Luck!
Moosestang/spyder7724:
I have also been having vibration problems witht he install of 4.10's in my 07 GT 5sp. Ifinally got it right on my third set 4.10 of gears. The first set were installed by a local SoCal speed shop, the second by a local Ford dealer and the third by a driveline shop. All three sets were FRPP 4.10's.The driveline shop finally got it right after about a dozen tries. They were as frustrated as me. Before I tried the driveline shop I also tried a PowerHouse aluminum driveshaft, but it only made the problem worse. I ended up using the stock driveshaft which gave me no problems with the original 3.55's.
Good Luck!
4th Gear Member
Joined: Oct 2005
Posts: 1,189
From:
RE: Can gears cause a vibration?
same here i had 2 sets of 3.73's and now a set of 4.30's all different brands. with the stock carrier they all did basically the same thing. the best i got it was with the 4.30 XP series motive gear set with the backlash set very loose (.017 yikes!!) which gave me an annoying clunk when i put the car in reverse and forward gears. what a freakin mess ford had. that was the purpose of that stock driveshaft with the CV joint. it absorbs a bunch of vibrations from the rear and some from the transmission also. instead of fixing the problem ford just tried to engineer band-aid fixes to cover it up like the hydro bushings, the sand filled panhard bar, axle weights and of course the 45lb. 2 piece noodleshaft.
2nd Gear Member
Joined: Mar 2007
Posts: 220
From:
RE: Can gears cause a vibration?
moosestang:
My vibration was speed related (90 mph +). It was bad enough that I thought I would tear up the u-joints in short order if I did not get it fixed (or keep my speed down). My one piece Powerhousemade it worse.Is your vibration related to speed orrpm's?
spyder7724, you are the only one so far with a plausible answer for this vibration problem, a bad carrier. By the way, my backlash is set at .024 and I am gettingthat annoying click too, but plan on living with it since there is no wine or vibration with the current set-up. If I ever find an Eaton for $100 I will buy it on the spot.
Good Luck!
My vibration was speed related (90 mph +). It was bad enough that I thought I would tear up the u-joints in short order if I did not get it fixed (or keep my speed down). My one piece Powerhousemade it worse.Is your vibration related to speed orrpm's?
spyder7724, you are the only one so far with a plausible answer for this vibration problem, a bad carrier. By the way, my backlash is set at .024 and I am gettingthat annoying click too, but plan on living with it since there is no wine or vibration with the current set-up. If I ever find an Eaton for $100 I will buy it on the spot.
Good Luck!
Thread Starter
6th Gear Member
Joined: Sep 2006
Posts: 11,278
From: Gainesville, FL
RE: Can gears cause a vibration?
My vibration is only felt at 3200rpms and it's gone by 3400. Not really noticeable in 1,2 or 5th, but definately noticeable in 3, 4. I'm curious to see if it's still there when i get the car back. i'm think it will move done in the rpm range because of the 4.10 gears. If it's still at 3200rpms what will that tell me?
I would take it to ford, but since my cars lowered, that's out.
I would take it to ford, but since my cars lowered, that's out.
2nd Gear Member
Joined: Mar 2007
Posts: 220
From:
RE: Can gears cause a vibration?
moosestang:
Your vibrationseems to berpm specific, not speed specific. The driveshaft and rearend vibraitons I had were definitely related to the rotational speed of the driveshaft and rearend (90+ mph), regardless of whethterthe carwas in 3rd, 4th, 5th or coasting. I am no expert, but since your vibration is rpm related and not specific to a certian speed itmay be something likea broken motor mount. let me know if the 4.10's fix or change it.
Good Luck!
Your vibrationseems to berpm specific, not speed specific. The driveshaft and rearend vibraitons I had were definitely related to the rotational speed of the driveshaft and rearend (90+ mph), regardless of whethterthe carwas in 3rd, 4th, 5th or coasting. I am no expert, but since your vibration is rpm related and not specific to a certian speed itmay be something likea broken motor mount. let me know if the 4.10's fix or change it.
Good Luck!
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