Im rewriting most of this to give it some fresh taste

From the beginning - We cracked open the diff, and managed to pull off the pinion bearing without breaking it. So far the only thing we have used is a new crush sleeve, and my car is an 03 with 85k miles.

My mechanic has done many rear ends before, but never a rear diff on an import before (as most are front) hes used to gms, chryslers, fords etc. So it was a little different for him.

We first felt around for an approximate backlash setting to start with, which turned out to be at .0020(ish) since the factory specs called for .0035, we adjusted to this measurement, but it felt way too loose. We didnt change the pinion depth from the Kia shim that came with the pinion and had a go at it, and it whined like crazy, you could hear that it was way too loose inside. We parked it immediately, and had another go on the next day.

Second day, we re-checked the pinion depth with the dye and it was spot on the old marks (used kia 4.77) so we knew the shim was correct, it was just the backlash setting. We checked the setting again, and it had actually tightened up to .0030 from .0035". Then we had an epiphany, and checked the tool itself. At last we found our problem, the tool wasnt measuring correctly, so after getting a measurement tool, we remeasured and found that the actual backlash was set at .025 thats hundredths, not thousands. No wonder it felt so loose.

We tightened it up to .004, and checked 4 corners of the gear and everything checked out. Went for a test drive and its as quiet as a baby, sounds 100% like stock.

Anyways, after a good two days of time consuming work we got the 4.77s popped in, yellow jacket installed (which was also a pita, bc the T clamp was missing) and even changed the oil and got realigned. Was a good day today

Thanks for everyones input

 

Sounds like a lot of guessing... When putting a differential back together, it's important to have the right tools and the measurements should be exact... no rough estimates. I'm not surprised that you received whining.

As far as the shim, what makes you think it 'looks' fine? I mean did you check the tooth contact?

Keith

 

Did you paint the teeth to make sure its riding on the correct contact patch?

And what shim came with your kia 4.77s? No shim came with my kia gears lol.


Not sure if maybe you over looked this but it is .0035"-.0043" inches or 0.09 - 0.11 mm also make sure that the dial indicator is set up properly and accurately measuring backlash.

 

I will PM you my number and help you out of your problem the backlash is only the tip of the problems you have, I am pretty sure that the pinion height is also wrong.

As stated, this is not a guessing game when setting up a gear box.

 

yep, glad i went with htg/puddydad. i was going to do it myself but decided it's worth it to just have the expert do it. i've had the gearing for a year and a half now and it's flawless...

 

Yes, we painted the teeth to check the wear pattern, everything was spot on.


The shim/spacer that came with my Kia 4.77s is inbetween the pinion bearing and the pinion itself, we actually missed this part at first, and tried to install the pinion without the shim and it wouldnt tighten correctly, we then looked over and saw the shim laying on the desk whoops! lol, slapped the shim on and the pinion went in much easier and the tooth contact was right on line with the old wear pattern

 

Thank you for the offered help, we were about to call, and then we found our problem (bad measurement tool) and everything worked fine.

I think I worded myself incorrectly, we werent guessing, just doing the backlash by feel to get it close, and then measuring it to bring it to the correct accurate specs.

Again thanks for the help though, im glad everything is in working order now

 

updated original post for new day findings!