How much whine is normal for a new sure grip rear end?

-
emnestor

emnestor

emnestor
Joined
Oct 2, 2009
Messages
232
Reaction score
4
Location
Va Beach
Just got the car together and now I am working out all the bugs. I was curious as to how much whine is normal for these 8-3/4 rear ends? I have a rebuilt a body 8-3/4 742 with 3:91 gears with a 4 speed man. I have a very slight whine when I am slowing down that i notice. Is this normal for a low geared rear end like this?
Also at cruising speed in 4th gear I devlop a slight vibration through out the car. I am thinking that it is the drive shaft needs balancing. If it were the drive shaft wouldnt I notice it in the lower gears as well and not just at 55-65 cruising speeds? Thanks
 
No whine is normal, any noise is a problem.

depending what ratio you went from the shaft is now spinning at a rpm it really never got to before...

No the shaft will not make a vibration at lower rpms
 
Ive been a member of the local MoPar club here in Austin for a number of years now and someone is always whining about how much they want one. Seems normal to me ;-)
Andrew
 
Thanks. is this a matter of adjusting the gears to get rid of the slight whine?
 
...........Depending on the gears, 1ce they whine ur pretty much stuck with it....possibly the pinion depth is wrong...i'll bet the guy that set them up tells u that they just need to wear in, its usually the opposite, they wear out...kim......
 
There are some ratio gears that over 4.88 can make some noise, but only at higher cruise speeds, most gears shouldn't make a sound ever.

The china copy cat stuff can be a issue with set up, and i believe they make noise mostly because they don't set up right and you have to read them and adjust to make them set up right, which is why i don't like getting involved with china stuff, when you set the pin height and find out it's afu and way off and now 3 hours turns to 6... Some shops i think get frustrated and thats it and get it the F outta here..

I have corrected gears that people came in with them singing from 10 to 70mph on the up and down side (had 3 like that , how they lived with it for so long is beyond me), had one jeep where they drove it like that for a year and a half, and i have got them quiet, if the shop knows what they need to look for and adjust for they can straighten it out, especially if this is new.

There are cases when they are driven hard and hammer the gears to a gouging effect on hard use and they create a high spot for the gears to run on when adjusted which can lead to other issues, re-setting gears that have been run long are a MF'er to read and set so don't wait.

.
 
When you put them (proper lube in diff housing) down you should slowly/'grandma-like' drive them, slide-to-slide turns for a little bit and they should be quiet. No whine.

And at low speed if you had a wobble in your driveshaft, it would be pretty epic- how you would not visibly see it with your naked eye would be a mystery to me
 
i had a slight whine in mine and it turned out to be an axel bering an easy fix and make sure you have proper end play
 
Thanks folks for all the helpful info.
The vibration I get is at lower RPMs at cruising speed in 4th gear. At higher rpms in lower gears I dont notice it.
 
Forget the rpms in each gear, the shaft is not doing what the crank is doing...

In 4th which should be your 1.1 ratio in the trans is the only time the shaft is doing the same rpm... Before that this doesn't matter.

You have a vibration at ____ MPH and it goes away or gets better a ____ mph

.
 
Got it.
I have a vibration between 45 and 60 mph. gets better after that.
Thanks
 
When I was choosing gears for mine I read some articles that said some manufacturers gears have a slight whine to them. They really should not whine if set up and heat cycled properly from the git go.
 
Can't tell by the first post,are the gears new or used ? Or was the housing complete when you got it ? When I buy swap meet pumpkins.....it's the luck of the draw. Last set(3.55 742) I got looked good,pattern and backlash correct,got a high speed whine on the drive side, quiet on the coast.Figured that having no idea how long they were or how many miles they have gone that nothing can be done.
 
You must log in or register to reply here.
-

Back
Top