Hi Guys, I recently installed a set 3.42 gears made by Quality gears which are one of the more expensive sets you can buy. I have a 72 Sportswagon. which I know can be noisier then a trunk car, but I get a howl noise at 40 mph it goes away after that speed and isn't evident before 35 mph, is it just a bad set of gears or what is going on ? Thanks Curtis
Curtis, how in depth did you go on the installation? Pinion depth, carrier bearing preload, pics of the contact patterns you can share? New bearings? Without that stuff it might be a crapshoot finding a root cause. Devon
Good question, I basically just bought a Richmond install kit and new gear oil and went to it .I have done rear ends on circle track cars with no problems, although they are so loud maybe something was wrong and I wouldn't have even knew it.Any other help would be great,thanks Curtis
That may be a problem. All the stuff I mentioned, and probably more that I forgot, is important for quiet operation and long term durability. Personally I wouldn't drive it any more until you can get into it again. Hopefully Jim ("monzaz" is his username here) will chime in. He's pretty much our resident expert. Here's his profile page with contact info: http://www.v8buick.com/member.php?3880-monzaz Devon
Yes - Pretty tough to figure with the info given. So what you are saying is that this howl is on present at a 5 MPH area? 35-40 MILES per hour? Could be a simple as a drive line pitch in the rear end angle you would never notice with the higher freeway gear or just a pinion bearing preload issue and that particular speed is where the bearing slides instead of rolling... it is a tough call. How loud is it? VAns are also very particular as they have a big cavity and tend to magnify the drive line noise also... Could be the gear is a bit off on the set-up slightly or it could be the gears is just a bit picking and may wear it in a few more miles...etc. Like I said if it had to say. Oh and a note...Just because gears are expensive does not make them good ones...lol. Also you can have the best gears in the world and if they are set up wrong they will be no better than cheap ones. I have actually had to go to a cheap gear set to find out a more expensive brand name gear was junk a few times. It is really a pot luck out there with parts these days. I am stuck in the middle with suppliers on one side and customers on the other. IT IS TOUGH.... Best to open up the rear and clean the ring gear in a spot with brake cleaner and shoot some pictures we can then see what the pattern looks like and recheck the back lash etc. About all you can do. If the pattern and back lash check out you will have to evaluate where you want to go. REPLACE THE GEAR or deal with what you have ... double check you pinion preload make certain it is not too loose or too tight. if the carrier can be pulled out by grabbing the carrier and pulling out the carrier preload is too looose... this could be also a cause of the howl - it will spin and flat after a certain speed and fall back on to the race at a lower speed could be happening at your 35 -40 range...??? Just trying to through out common sense mechanical workings here. Jim J D
I have to agree, we need more info. It is really important that you know how the pattern is affected by your pinion depth and backlash. Usually if you go with your original shim for that housing it is the best starting point. Even if you have the gauges for pinion depth it is usually faster to setup the gears with trial fit bearings, ones that have been modified to slide on the pinion without pressing them on. This lets you assemble and disassemble the diff several times without using pullers on the bearings every time, and you don't need to use a crush sleeve until you are doing your final assembly, just tighten the nut "carefully" until you get the right preload on the bearings. The crush sleeves need replaced once you crush them, although some people will flatten them out to stretch them back. If you send us some pictures we'll let you know how your pattern looks. You need pictures of the drive and driven side of the ring gear teeth with the marking compound showing the pattern. I use "Quality Gear" a lot, but we do get the odd bad set, they are not OEM quality. But heck I remember having 3 sets of bad GM OE gears in a row years ago, they were .050" out of the depth setting they had marked on them, and couldn't be setup (maybe they though the measurement was in millimeters instead of thousands of an inch?). They sent a GM rep from head office because they didn't believe it. We installed a "Quality Gear" ring and pinion- problem solved. If you just assemble them without checking the pattern and use the shim that goes with the housing, you have a 30% chance of getting it close enough it might work well. 40% chance it might do for a while, but be noisy and/or wear out, and 30% chance it will cause damage.
