3.73's are howling like a &^%$
Thread Starter
Launching!
Joined: Mar 2003
Posts: 274
Likes: 0
From: Rochester, NY
3.73's are howling like a &^%$ Well I just got done installing everything in my sig, and the car is running fine... the valve train has a little clatter now that I've had it around 4-5K rpm, but that will be fixed. However, my red TA sounds like a fire engine coming down the road from the Richmond gears. I've read on here that they are loud, but god &^$% they can't be that LOUD.
When we first did the install (my buddy who helped me do all the mods is very experienced, and has done many rear ends) we set up everything to spec, backlash was an average of 8 thousands around the carrier. I took the car out for its 1st drive and right about at 15mpg and all the way up it screamed and howled on accel, decel and cornering. So we went back in and removed all the shims from the pinion so its as far back in the housing as possible, and re adjusted the shims on the torsion. Off hand I can't remember what the final backlash was, but it was more than before. So we took it out again and it still screamed and howled on accel and decel... seemed to be worse on the decel this time around, and the cornering was quite I believe.
Is there anything else I can try to do to get it quieter?
I was ready to buy a 9" or 12 bolt this morning (originally I was going to do this next year) until I read all the problems everyone has had and the fact that it takes 6 weeks to get delivered isn't helpful either. Any suggestions\info\help would be great.
DKL
When we first did the install (my buddy who helped me do all the mods is very experienced, and has done many rear ends) we set up everything to spec, backlash was an average of 8 thousands around the carrier. I took the car out for its 1st drive and right about at 15mpg and all the way up it screamed and howled on accel, decel and cornering. So we went back in and removed all the shims from the pinion so its as far back in the housing as possible, and re adjusted the shims on the torsion. Off hand I can't remember what the final backlash was, but it was more than before. So we took it out again and it still screamed and howled on accel and decel... seemed to be worse on the decel this time around, and the cornering was quite I believe.
Is there anything else I can try to do to get it quieter?
I was ready to buy a 9" or 12 bolt this morning (originally I was going to do this next year) until I read all the problems everyone has had and the fact that it takes 6 weeks to get delivered isn't helpful either. Any suggestions\info\help would be great.
DKL
Re: 3.73's are howling like a &^%$ It's all about the install. Pinion depth is key. Make sure that is PERFECT, first. Backlash isn't all that important in regards to noise as pinion depth is. Tear it down and setup the pinion depth properly and it'll cure it.
Thread Starter
Launching!
Joined: Mar 2003
Posts: 274
Likes: 0
From: Rochester, NY
Re: 3.73's are howling like a &^%$ Thx for the responses.
My buddy was talking to his friend who is also a great mechanic. He suggested re measuring the housing and find its true center point to make sure our measurements are correct, as you suggested... which we also did again yesterday before we removed the pinion shims. To do our measurements we ran a straight piece of iron across lower mounting holes for the torsion brackets(the surface that the 2 brackets that hold the torsion bearings in place at each axle opening in the housing), and then measured from the bar to the pinion to get its depth.
Does this sound correct?
My buddy was talking to his friend who is also a great mechanic. He suggested re measuring the housing and find its true center point to make sure our measurements are correct, as you suggested... which we also did again yesterday before we removed the pinion shims. To do our measurements we ran a straight piece of iron across lower mounting holes for the torsion brackets(the surface that the 2 brackets that hold the torsion bearings in place at each axle opening in the housing), and then measured from the bar to the pinion to get its depth.
Does this sound correct?
Re: 3.73's are howling like a &^%$ This does a great job explaining it: http://www.streetrodstuff.com/Articl...rential_II.php
Re: 3.73's are howling like a &^%$ This way is really easy too, less confusing:
Since the mating surface is usually not precisely on the carrier bearing centerline, the difference (offset) must be measured and either added to, or subtracted from, the measured distance, to determine actual pinion depth.
To determine the offset, measure the carrier bearing race and divide it in half. Then measure the distance from the bearing cap mating surface to the bottom of the bearing bore. The difference is the offset. If the measured distance is less than half the face diameter, the difference must be added (to the pinion depth measurement) if it's more than half the race diameter, the difference must be subtracted.
As an example, half of the 3.064" diameter race used in a Chevrolet 12-bolt rear axle is 1.532". If the distance from the mating surface to the bottom of the baring bore is 1.512", the surface is .020" below the bearing centerline, so .020" must be added to the measured pinion depth to determine the distance from the back of the pinion to the carrier bearing centerline (pinion depth).
Since the mating surface is usually not precisely on the carrier bearing centerline, the difference (offset) must be measured and either added to, or subtracted from, the measured distance, to determine actual pinion depth.
To determine the offset, measure the carrier bearing race and divide it in half. Then measure the distance from the bearing cap mating surface to the bottom of the bearing bore. The difference is the offset. If the measured distance is less than half the face diameter, the difference must be added (to the pinion depth measurement) if it's more than half the race diameter, the difference must be subtracted.
As an example, half of the 3.064" diameter race used in a Chevrolet 12-bolt rear axle is 1.532". If the distance from the mating surface to the bottom of the baring bore is 1.512", the surface is .020" below the bearing centerline, so .020" must be added to the measured pinion depth to determine the distance from the back of the pinion to the carrier bearing centerline (pinion depth).
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Re: 3.73's are howling like a &^%$ Funny, Ive also been told that, but why do so many manufacturers agree harder metals used in stronger gears can make more noise. Who knows. IE Randys R and P fliers claim "Our Yukon gear is designed to RUN QUIET and LAST LONGER than other after market gear sets." It also mentions the oem are the quietest available.
Re: 3.73's are howling like a &^%$ Manufactures say this b/c they know that most installers are pretty inept at doing these things so instead of customers bitching at the manufacturer they'll go bitch to the installer, and rightly so. Also, with the harder metal you do setup the risk of being more prone to noise even with a good installer just b/c of the physics of it all. But they can be set up to be quiet.