gear pattern changed.
This is a discussion on gear pattern changed. within the Drivetrain forums, part of the LSx Technical Help Section category; As some of you have been following, I switched to a 3.90 gear which was quiet and the pattern changed ...
06-12-2008, 08:06 PM #1
gear pattern changed.
As some of you have been following, I switched to a 3.90 gear which was quiet and the pattern changed after a WOT run. Tried another, it whined on the coast side, switched to 4:10 and the pattern changed again just like the first 3.90. When the guy install the gear, he illustrates good contact. After driving the car around the block the pattern is clearly on catching the lip of the ring teeth. What is he doing wrong? We're trying another 4:10 tomorrow but this one is going to be a GM original instead of Motive high performance.
06-12-2008, 08:31 PM #2
Also if the carrier isn't shimmed and preloaded properly on its bearings it can fluctuate also.
If it is only catching on edge of tooth than the pinion depth is too deep and the pinion needs to be shimmed closer to the ring gear and the proper backlash set with the correct preload. Which rear end do you have? Rears can be tricky to set up properly. The use of a dial indicator with a jig can allow you to measure pinion depth and backlash cause every set of gears is unique and comes with a recommend pinion depth from centerline and recommended backlash setting. I can set them up without dial indicator but it usually means pulling and shimming a few times until I see a good pattern. Once you actually run the gearset in a certain pattern if it is wrong the gears are virtually ruined as you have experienced. Hope that helps, I build many fbody rear ends for my customers and my various cars.
I'm not sure what techniques your guy is using but I can tell you it takes a very close eye to detail and the right experience and tools to successfully install gears, bearings and shim properly. Even having said that some aftermarket gear sets still have a tendency to whine a little even with an ideal pattern and preloading. I have put much time, hands on, research and experience into the dynamics of properly building rear ends and it is more complex than some would think. Many shops and dealerships dont know what they are doing not to be rude, but its true you would be amazed.
Last edited by BlwnCamaro; 06-12-2008 at 08:45 PM.
06-12-2008, 08:53 PM #3
furthermore dont mean any disrespect to your mechanic there are actually many variables and deltas in the realm of gears. It is not uncommon to see a failed aftermarket gearset that didnt or wont take. If you delve into the world of gears and rears it does happen.
Some further anomolies that go beyond human error in terms of correct shimming, torqueing and preloading, include rear end housings that are tweaked and out of spec, defective noisy aftermarket gearsets, defective bearings, bad bearing races. So as you can see there are many variables.
Did he also replace all of the pressed in races in the rear end. Sometimes people dont replace pinion races cause it can be a pain but that can be devastating.
06-13-2008, 07:33 AM #4
06-14-2008, 04:39 AM #5
update, he couldn't get the gears right so he put the old one's in and gave my money back. Surprisingly the old ones are fine when the 3 diff aftermarket gears whined and howled. Go figure.
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By SteelmanLS1 in forum Manual TransmissionReplies: 15Last Post: 08-02-2007, 08:12 AM
By JehalinTA in forum General HelpReplies: 4Last Post: 07-19-2007, 06:24 AM
By Rhinohuey in forum Almost Anything GoesReplies: 25Last Post: 07-11-2007, 01:22 PM
By Even10Flow in forum DrivetrainReplies: 5Last Post: 07-02-2007, 11:43 AM
By JLSain in forum Manual TransmissionReplies: 3Last Post: 09-27-2005, 10:03 AM