After 4 TSB attempts and a whole new rear end, I still have subtle but noticable gear whine around 40-50 mph on decel. It's more of a slight flutter than a whine. It's not bad enough to keep tearing the rear end apart, but it's still a bit annoying. I'm resigned to accepting it considering that a whole new rear end from the factory still whines a bit.

So, how much does Dynamat reduce rear end noise? Where should I put it to dampen gear whine?

 

It may help a little bit. I would concentrate on the sheet metal under the seats, behind the seats, and in front of the trunk. Try and put it as near as possible to where the control arms go into the body of the car. And I wouldn't expect a huge benefit on the whine.

You can also try changing to a different rear axle lubricant. Red Line Heavy shockproof gear oil has been reported to reduce whine, ditto for the Lucas additive.

 

I'm about to go down your road and hopefully the whine will go away after this first and hopefully last rebuild. But as far as dynomat I don't know if it would work since the with the whine or flutter since it comes from the rear end itself vs vibrating through the body. But if all else fails turn up the radio and crack the window.[8D]

 

Ho Rich! I can't believe someone else thinks like me. I ordered a roll a few weeks ago and will install it this weekend. I'll definitely post back and let you guys know how much, if any, it reduced the noise. Don't spend your money until I let you know!

 

cool - look forward to your post. So what's your situation - you also have seemingly unsolvable gear whine?

 

Well, mine is really a bearing type high pitched whine that starts a 50mph and goes up from there. It stops upon releasing the accelerator. It's most noticable when just cruising. I'v head the rear gears redone twice by an aftermaket shop and they replaced everything that is in TSB 05-20-12 except the differential bearings when they did their job. So, I'm assuming it's the differential bearings.

I don't want to bring it to Ford b/c they'll put the stock 3:31s back in which I DON'T WANT, and if I tell 'em I got 3.73s they wont warranty the work, so I'm left with 1: Live with it and try dynamat 2: Get a whole new differential. 3:Get the aftermarket shop to replace just the diff bearings. But, the likelyhood that the gears in there now, now that they have worn a pattern, will not make noise when they are reused is very high. Meaning, I'll likely have to buy a new fresh new gear set too, and this issue has already cost me too much money and time.

 

Well, I installed two layers of PowerMat (Just as thick as dynomat and alot cheaper) under the rear seat and on the vertical surface just in front of the rear seat(behind the rear seat passengers legs).

I would say it reduced the noise by about 25% but still audible. Although, in the process, a slip of the razor knife cut a beautiful gash about 3" long in the center of the rear seatback! What a F%$$&N idiot I am! I swear this car fights me on everything I do to it.

So I would say it's not worth it when you factor in the cost of the new rear seatback I'll be shellin out LOL. But otherwise it might be. I think if you placed it under the rear portion of the center console also it would reduce the noise even more, but right now I'm not bothering.

I just changed the oil today and put on a coat of Turtle Wax Ice b/c it's going in storage for the Winter prob next weekend. But I did read the post about the Redline Oil, and I just may order some tonight. With my luck, when I'm changing the gear lube the rear diff will fall out!!

 

Was it hard to install? How long did it take?

Also, how do you like the 3.73s? Is there a noticable difference from the 3.31s in daily driving? I'm thinking if I'm gonna have gears that whine, might as well have upgraded gears that whine.

 

No it wasn't hard to install took about 90 minutes. I've done it on other cars I've owned so once you know haw to work the stuff it goes pretty easy.

The 3.73 are awesome in my auto. Definite improvement in around town driving, not so much so at WOT.