Fman67

:bang: Well...i finally had gears done by a very reputable installer. My car has always had gear whine since new...i went with FRPP 3.73's. When my installer drove car before new gears...he too noticed "whine" in rearend. When he got it apart...he told me that gears were meshing good...but there was too much backlash. He says 13 thousanths! He installed gears....and much to his surprise...still had gear whine....but only on deacceleration. I had whine in both acceleration,and deacceleration before. Also there is a thump thump thump sound as you are coasting down to a stop. He has kept the car...and has made a bunch of calls to Ford and other sources for why this may be! This guy is really the bomb when it comes to gears....never had a problem with any cars done by him before. I trust he will get it right...but it is blowing his mind. He has got the gears meshing perfectly.As far as the gear change goes...i only put a few miles on it...but all i can say is that there is a big difference in torque,better shifting,less lag off idle,and just all around better response...i have yet to really get on it...cause i want to get these issues fixed first. I will post my overall opinion when we get it sorted out! Did anyone notice that the stock panhard bar has "sand " or something in it...possibly used as some sort of "sound DAMPER"??? If anyone wants to chime in on what might be wrong...let me know! Thanks all!

169stang

I believe Ford spec for backlash is .009-.010. I thought the whine was caused by the mesh or backlash being too tight. If the backlash is too loose, you'll hear that clacking of the gears when driving and you let off the gas into a coast and then clacking when you get on the gas again. I've come to realize that doing gears is more than just setting the pinion, throwing shims in and putting it back together. I wonder if there is a sweet spot for the pinion and shim size.
Someone, please correct me if I'm wrong, but I think you can get the same backlash within different pinion settings and shim combo's.
The pinion moves in and out while the shims move the carrier left to right. I'm not sure. I guess that's where the wear pattern comes into play.

Clem

Fman, I have a similar situation. I picked up car yesterday after having the 3.55 swapped out for 4.10's, along with other mods (JLT, XCAL2 + Fuzion 255's), and I'm getting "The Whine" as well. My installer is also very reputable and says that my stock carrier is less than perfect. He predicted some noise before the thing even came off the lift and tells me that they tinkered with it for quite a while. Something about varying backlash readings. Is this possible or just a "cover your ****" move? I have only driven 25 miles or so and haven't hit the highway yet. My whine comes in around 40 and starts to taper off at 60. Haven't been much above that. Thankfully it pulls like a pig now , but the noise going to wear on me quick. I also feel a bit of chatter on decel. Is she too tight?

mikem

Got my FM 4:10,s installed last week.Came out perfect.Has the same decelarating whine it had when new.Pulls like crazy, cant wait to get back to the track.

lodom

There was a post from along time ago on another BBoard, when the Mustangs were being held for quality issues, saying the carriers in the rear end weren't machined correctly. This might explain the noise many of the owners are getting even with a good set up. Both of the S197's I've driven had significant gear noise on decelleration.

grey05gt

What is the deal with this issue, the 8.8 has been around for awhile with no problems until now, the only differance is there is only one mount on the carrier now instead of two for the upper control arm.

Blk05GT

I am sure there is something wrong with my carrier. I had 4.10s installed and they whined like crazy. I took it back to the shop and had them take everything out, measure again, check the mesh and reinstall everything. I witnessed them measure backlash, shims etc. Took the car out and it still whined.

I was fed up at that point and took it to another shop and got rid of the FRPP 4.10s and had them install a new set of Motive 4.10s and had them reshim it. I again watched the entire installation and I trust that they did everthing right. The car still whines although not as bad as before.

azoufan

Yeah me too, both myself and another guy had 4:10's installed by the same person. We both watched him check and doublecheck everything, gears are meshing perfectly, get a wine under very slight load from 45-65 Mph. Both are FRPP sets, I have no idea why, but it seems like ALMOST everyone is getting this. There are some folks here that have no gear whine, but they seem to be the exception, not the rule.

Some people will tell you it was a bad install, period. Too many people with installers who have years of experience being very careful on these says otherwise to me. I don't know, I'm not arguing with those who claim it's a bad install, but if that's the case, then there are like 3 people in the world who can install a set of gears correctly.

Sean

Redfire1

I had 4:10s installed in my Chevy truck by an ouitfit that knows what they are doing. They were Richmonds and they whined at around 50, especially on deceleration. So I had the same outfit replace them with a US Gear set, and these are great. No noise at all. But lodom might be right about the machining issues. You might have to replace the entire rearend, and still have no guarantee the noise will stop. Solution: Get SLP Loudmouths and turn that cd player UP!

Fman67

My installer is miffed...he has kept car and Ford tells him that the specs he set gears at is perfect...they also told him that they were not going to use Synthetic anymore...and to try old style gear lube 140 wt.. he changed fluid and still got whine...he is tearing it all down again on Monday...also a litlle interesting note...the stock Panhard bar is full of sand or metal shot or something...he wonders if it is some kind of dampening device for noise in rearend...i did notice whine in stock form was getting worse after i switched out panhard bar and brace for BMR stuff...not saying that there products are not good...but they didn't put any sand or whatever in them...why did Ford?

Fman67

I got that chatter grind sound just as car is coasting down...comes in about 30 mph or so...very disturbing...my installer checked with Ford and Drive Train Specialties on backlash settings and he is right on the money. They told him to try a different lube(heavier weight). He did...and still has whine and chatter. He pulled it back apart...and is going over it again on Monday...he is bafled? I wonder if we got bum rearend housings or carriers?

Fman67

:scratch: Huh....i wonder...my installer is baffled. He has taken it apart again and will be going through it on Monday again. I'm bummed!

Fman67

I agree with you...something is up!

Fman67

You seem to have done it all with these cars...what did your car do in stock form as far as whine...how about your gear changes? What did you notice? What is your take on stock panhard bar?

97PSD

Well I just had the Motive 4:10's installed a few days ago, the only noise I've noticed is when I'm in 3rd or 4th and let off the gas to coast a little. More of a low pitched whine rather than the higher pitched whine coming out of the tranny. I can't honestly say it wasn't there before and that I'm sure it's coming from the rear end, everything sounds a little different with the Borla's in . It does go away immediatley as soon as I apply power and as long as I have the power on there is no whine no matter what speed I've been at. Sounds like from previous comments this may be normal but I may try some sound deadening material in the trunk to tone it down a bit.

LordBritish

My 3.90 motive gears whine pretty loud at 50mph when coasting.

It's quite annoying.

I'm taking it back to the shop to be adjusted.

When I accelerate or when coasting above 60 mph or below 45 mph, the noise is much less.

I think air resistance above 60 mph adds presure to the gears (reducing noise) and speeds below 45 mph have less pressure (reducing noise), and accelerating increases pressure (reducing noise). That's my theory.

I think at a certain speed the factors of air resistance and friction combine to create gear noise at a certain speed - again, that's my theory.