Gear install/noise issue

[not a gt]

Originally Posted by Mach828

If your pattern looked like you posted, then pinion depth is probably good.

So can pinion depth be ok , but pinion preload be off, or are they one in the same? If pinion depth is correct, shouldn't whine on de-cel??

[Mach828]

I'd just tighten down the pinion nut a little more and see if it fixes it. Worse case, you crush it too far and have to tear it down, which you are planning to do anyways. Best case, saves cost of gears, labor, fixes the whine, and you spend 10 minutes of your time.

[Dan03mach]

Originally Posted by not a gt

The one part I am confused about..when you put the in/lb torque on the pinion, is this with gears in as well so you are checking force of pinion TURNING the gears??

No just the pinion gear not with the ring and diff installed.

[Dan03mach]

Originally Posted by not a gt

Thanks, I wonder on our cars what is a good starting point for the pinion shims if gear has been removed and starting from scratch?

.010-.015 Start low and work up from there.

[lcaptmorg]

If im starting from scratch I typicaly start a little higher like .028 or so on a ford 8.8 but there is no harm in starting low and adding shims. Very time consuming but you will quickly learn how moving the pinion out effects the pattern. Unforutnately as you move the pinion out then the back lash will decrease so continue to check that as well to make sure it in the normal range. .008-.015. For street gears I like them .008-012.

Take and old inner pinion bearing (make sure it is the same brand as the new one to be used) and dremel or die grinder and remove a bit of material from the inside so you can slide the bearing over the pinion. This will allow you to mock up the pinion as many times as you want prior to pressing on a new bearing for final assembly. Its a heck of alot cheaper than a pinion depth tool and honestly I think it works better.

Im also a fan of solid pinion shims for setting pinion bearing preload but that's just preference

[not a gt]

Well short and sweet..went back to dude yesterday, it is worse..now whining LOUD on drive AND decel,(starts at about 40 mph up to 60, then exhaust takes over, when coming to a stop, loud whiirrring sound) he set backlash at .006, spent 7 hours, I did the bearing grinding trick, think pinion shim is like .020, no torque wrench on pinion preload (I brought a torque wrench but the lowest it had was 50 in/lbs..I did bring everything else). So, I have bought a THIRD set of gears, fluid, etc..I just did a total, after paying a dude here in my area who is a beast on gear swaps(other mechanics go to him), I will have $955 in a 4.10 to 3.73 gear swap

[Mach828]

Its not the gear set!

[not a gt]

Originally Posted by Mach828

Its not the gear set!

I know, problem is I am driving about 110 miles home after install and just dont want to take the chance they are set in..they would be perfect for a drag car and not a DD, I will be doing a for sale thread..at $100 shipped , great deal for someone on a low mileage Ford racing gear

[OWmach1]

I just had my 31 spline diff, 4.10's, and summit axles installed at a shop. I brought home the rear end and there is no whine at least for now. Some told me to take it easy for the first few hundred miles, but I honestly couldn't resist it so I did a few WOT passes 2nd and 3rd grandma shifting after putting about 80 or so miles and so far no whine accelerating or slowing down. I think it all matters on how its installed and the place I had it installed is strictly a rear end repair shop.

[PeteEpple]

sorry to chime in late... i haven't read every post so if this is a repeat I apologize.

When gears are made, they get lapped in before being packaged. In most cases somewhere on the box is the factory specs (pinion depth and backlash). To really do gears the right way they need to be set up to those specs. The pattern looks pretty good (a touch deep if anything), but if the pinion depth and preload aren't right...

If the gears are installed and they make noise, they can, in very rare instances, be re-setup and not make noise. But that is uncommon. You really need someone who knows what they are doing.

And for the record, gears are not something you do by feel. My rearend guy is the best there is and I've never seen him do anything with out measuring EVERYTHING multiple times! If you want to come to Tampa I'll give you his number!

[lcaptmorg]

Pinion depth is typically stamped on the face. Measured from the centerline of the axle housing . Pinion depth tool or some creative tool building with a depth mic and some math will give you the shim.

Honestly have never seen a number with gears for backlash other than the range for install.

.006 is to tight for sure and undoubtedly someone who does it by feel for a street car is asking for problems. Very very unprofessional as well.

Have done a few at the track like that but who cares what they sounded like and only needed to go a few rounds anyhow.

[not a gt]

Well, had THIRD set installed and no noise at all...silky quiet and smooth. Guy showed me and I will post a pic, he used marking compound on this set to see what he had...the very top of the tooth and only a 1/4 " hitting ring gear, it was the outside of the tooth only at the very top at the edge (this pattern was different than the one above post, pinion moved or something since it was just hitting gear and painted different)..this guy was done in 3 hours and said he couldn't believe how far off pinion was and didn't think sleeve was completely crushed (and he has backlash at .10)...so that is done, to reward myself I put new clutch and brake pad..holy s**t !!, 2 hours and I had to trim some of the rubber trying to stretch on, a bad blood blister later and..



Thanks for the help guys, glad it is over.

[not a gt]

Here are the pics, the guy that did them correctly was smart enough to paint gears to see what he was working with, what do you guys think??

[ubenjewed]

What would cause a crush sleeve work just fine as long as you drive it like grandmaw but as soon as you get on it one time, it loosened up and leaked like a stuck pig. I have rebuilt it three times and 8 (yes 8) crush sleeves later no dice. What am I doing wrong. I changed to 4.10 and replaced everything.

[bluoval]

Glad you finally got it solved. Half the battle on a gear install is finding a qualified person to do the install! I had to have mine done twice before they were done correctly.

[lcaptmorg]

Originally Posted by ubenjewed

What would cause a crush sleeve work just fine as long as you drive it like grandmaw but as soon as you get on it one time, it loosened up and leaked like a stuck pig. I have rebuilt it three times and 8 (yes 8) crush sleeves later no dice. What am I doing wrong. I changed to 4.10 and replaced everything.

How far are you crushing it? To what preload? Did you back it off at all after crushing? A solid shim might be a solution for you.

[ubenjewed]

25 inch pounds and not backing off at all.

[lcaptmorg]

Thats really odd. I have heard of crush sleaved loosening up but only guy that were making hard hits the track over and over.