I've had my 4.10s for about a year and a half now. They have always whined a little bit but recently they have really gotten louder and I get this terrible vibration at 70mph+ with just the right amount of throttle (I'm not sure this vibration is due to the rear end, it could be my tires - BFG KDW2s - or maybe something suspension related). The other noise they make is a kind of whirring noise when I'm slowing down to a stop and out of gear. It is barely audible if at all when I'm in gear except in 5th gear going 50+. At those speeds I hear pretty distinct whining whether I'm in gear or not.

I changed my fluid about 6 months, 5k miles ago with royal purple 75w90. Which was a year and probably about 5k miles after I had the gears put in. I'm about to change the fluid again just to be safe but I wanted to ask you all if this whining is something to worry about. Is my rear end going to go boom? That would suck so I'd be willing to do whatever I can to prevent that from happening. I have a shop in mind if the gears just need to be replaced/reinstalled but that will be pretty pricey and the warranty with the shop I had it done at (different than the one I would take it to now) is long since expired. I've heard an aluminum driveshaft will lower vibrations a lot and make things a lot easier on your rear end so would that help with the whining or prevent any damage? Would a different gear oil help like 75w140 or adding extra friction modifier? Please give me any adice you can, guys. Thanks.

PBF

 

You need to have a new set of 4.10's installed. The problem w/the whine is Backlash set wrong. 4.10's need to be set tight @7k. Then it will wear into an 8k backlash after a little driving. I advise a new set of gears. Also try this, when your turning does it make a heavier whine? If so, spider gears bro. Then you'll need to seach craigslist!

 

most people on here think the wine is just what gears do.... and they dont understand they whine from the backlash being set wrong.




but yea, what he said.

 

...Back Lash needs to be set correctly! ...sounds like a bearing might be going bad a well...

 

I've experienced going the easy way out & its always bad. You need to find a great mechanic, mine just happens to be a master tech @ planet ford lol. Every mech has a personal backlash they like to use but most use between 8 & 12 thousands measured by a micrometer. I just like mine tight for the amount of racing I do. If you have any questions visit wittenperformance.com then choose services & they will answer any performance question you have. Good luck

 

I realize this was a problem from when they were installed but I want to know why it has gotten worse. Are the gears themselves going to be damaged if I take it in or will they just be able to fix the backlashing on the gears that are already there? Could the bearing be making the extra whirring that wasn't there before?

 

The numerically higher the gear ratio the noisier the gear, as per any mechanic who knows a damn thing.

4.56s are guaranteed to whine, if you have a set that doesn't, your blessed, thinking about gears in the 5's? Definitely gonna whine....as for 4.10's they are noisier than the stock 3.27's

People have the belief that 4.10s or higher numerical gears should be as quiet as stock, but they live in a fairytale.

The vibration at 70+ is most likely your stock driveshaft whipping around.

 

Hmm, so would you care to elaborate how you came up with the conclusion that just because gears are numerically higher they are automatically going to whine? After all, they are installed the EXACT same way that the stock ones are, so what makes them automatically whine Mr. Master Mechanic?

 

I'm w/Black35th bro,you don't put a drag rear in a street car & most drag friends of mine can slap a gearswap & be back on the track in no time. May not be perfect but it'll hold a run or two. Any street gear when set "correctly" will hummm like a charm but not whine. Back to the question: 1st off always use friction modifier! 2nd, when was the last time you dropped your shaft? If you didn't mark it & jacked the bolt pattern up there's a problem that could have a minimal effect on your input shaft so be careful not to damage any worse. This could damage more. Here 2 options. 1/Easiest way out, have it drained look @ the gears check for fractures & a decent pattern. If all looks good, look inside & spin 1 wheel, look closely @ the spider gears. If they're chipped hit me back asap. Your in some crap. If you see nothing make it thick as all hell & pray for the best. Option 2: anytime you reset the gears it changes the tooth pattern weakening the gear. You need FRPP 4.10's w/bearing kit & Royal Purple. If needed get a matching diff for about 40 bucks for back up.

 

That is the dumbest thing I have ever seen posted on this forum.