I'd talk with Martin at Mobile Gears at 959-306-2805. He has a mobile truck that either comes to you or he may have you come up to Corona where he rents a shop on the weekend. He does a couple regears a day, he's one of the true few experts due to how many he has done over the years. He did some work for me a couple months ago.
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Or John Lemieux at All 4Wheel Drive in Corona. He's a little more costly than Martin because he has a shop he has to pay rent on. Those two are the best around.
Or if you absolutely want someone in Escondido where I have lived for almost 30 years, go talk to Kenny at ORW on Auto Parkway. He's now the manager but he used to be their gear installer. They're good about handling any issues that come up. Kenny installed some gears for me about 14-15 years ago that developed a problem within a couple weeks. He apologized profusely for the problem and took care of everything including new gears in the rear without issue. A bad install can sometimes happen to the best of installers so make sure you don't try to go cheap with an unproven installer.
Also, no matter who does the installation, make sure to ONLY use conventional gear lube like an 85W-120 during the break-in. Don't use a synthetic during the break-in, the gears will get hotter if you do. I continue to use only conventional gear lubes after all my installations.
What size tires and what transmission are those 4.88 gears for?