i need 2 replace my axel, bad poping noise when i turn, but cant find right size on 2001 Hyundai Elantra

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Recently I paid my buddy to help me change out my axel on the front passenger side. we removed it but when we popped in the new one the diameter of the shaft that inserts into the tranny was too small, it just turned in place not grabbing any of the ridges along the shaft. i visited 4 O’riley auto parts, 2 auto zones, 2 pep boys, and they all carried the exact same(wrong size) part. my car it stock and i can’t figure where to find the correct part for my 2001 hyundai elantra, and i need help the popping keeps getting worse, any ideas why they would be different sizes. Please help, I’ve hit a dead end. Thanks
(2) Answers
(5) Comments
Well now is it auto. or manual trans?? Is it ABS or not?? Try NAPA! Give production date and vin number.
Thanks to all in taking an interest in my problem :)

It's Automatic, the axel i removed has the abs gear but the gear doesn't link up to anything(the wheel hub has been replaced but not the axel). Also, i checked the manual trans axel, abs axel, even the driver side axels but they all were the wrong dimensions.
When you installed the new axle did you SEAT it into the diff. gear properly? Did you measure/compare the shaft diameter to the old one?
Something just dont add up, i guess you know this though. It should be a cut and dried parts look up.
Yes, the axel set all the way in, but the diameter was smaller than the one removed, everything else on the axels were the same, the replacement was just not as thick as the original on the end that enters the tranny.
Maybe a dealer would save time and stress.They might get the right part(hopefully).
Yeah, im saving that as a last resort. As dealers seen to enjoy bending people over when it comes to service or parts.
If the aftermarket axle is $150.00 and the dealer wants $300.00 (for the right one) How much is your time and aggravation worth to you? Sounds like you've got lots of wasted time in it already!!!!......But I'm not made out of money either , so I do understand the basic idea! Hope you get it. good luck.