Step-by-Step Replacing Rear Axle Seal & Bearing w/ABS (1st gen Tacoma or 3rd gen 4Runner)

I recently discovered a dreaded gear oil leak on my 4Runner and then a few days later on my Tacoma - and knew it meant only one thing - it was time to change the rear axle seals (and bearings and brake shoes since they were now saturated with oil). In addition to the story of the repair, I figured a detailed set of instructions for anyone wanting to tackle this themselves would be nice to put together, since it's hard to find that written down in one concise place (maybe even impossible before now). These are based on the videos by Timmy the Toolman, which were a great resource, as always. Also note: some of the links are affiliate links, and I may earn a commission if you purchase using them, but that doesn't affect the parts/tools I've recommended; they are the same ones I used!

This is of course based on the Factory Service Manual (FSM) description, but varies slightly (to make things easier) and doesn't require flipping back and forth between many different sections.

So let's get started.

Required Parts

• (2) Dust Seals (90313-48001) - one for each side of the axle
• (2) Axle Bearings - one for each side of the axle; oil washes out grease.
  • '96-'00 4Runner or Tacoma - P/N: 90363-40020-77
  • '01-'02 4Runners or '01-'04 Tacoma use P/N: 90363-40068
• (2) Inner seals for axle housing (90310-50006) - these are the actual axle seals
• (2) Axle Housing Tube O-rings (90301-88077) - one for each side of the axle
• (2) Snap rings for retainers (90520-36045) - Optional, but strongly recommended. Toyota says to replace these when doing the job.
• DOT3 or DOT4 brake fluid
• 3qt 80W-90 Gear oil for rear diff
• Crush washers for rear diff

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...and Tools
As far as tools go, there are several specialty service tools (SSTs) that you'll need to complete the job. While these tools are technically optional, and you may be able to fabricate some stand-in yourself, I cannot stress enough how much easier they made this job. If you're tackling this yourself, buy all of these tools - especially the Rear Wheel Axle Bearing Puller & Tone Ring Tool/Installer - it is frankly one of the most well-designed tools I've used for its purpose. They will double the cost of the job, but it's still less than half of having Toyota do it, and you have the tools for next time and other jobs!

Specialty Tools

• 20 ton press from Harbor Freight
• Rear Wheel Axle Bearing Puller & Tone Ring Tool/Installer - used with the shop press to both remove and install various components on the rear axle. Amazing tool, worth twice it's price, and you're supporting a fellow gear head in the process. Plus, this tool works across much of Toyota's truck lineup - 1st, 2nd, and 3rd gen 4Runners ('84-02), 1st gen Tacomas ('96-04), older Hilux, T100 ('92-97), and 1st gen Tundras ('00-06). It's also available with a late model adapter, adding 2nd & 3rd gen Tacomas ('05-present), 4th & 5th gen 4Runners ('03-present), 2nd gen Tundras ('07-present), all FJ Cruisers, and all Sequoia's. And there's an eBay Store with more variants, sweet. (Note: I'
  
• 3” ABS cleanout, with cap - to seat the new rear axle bearing.
• OTC 4507 Seal Driver Kit - to seat the new rear axle seal.
• OTC 4579 Seal Puller Kit - optional, to pull the old rear axle seal; I recommend purchasing this puller - I didn't, and the seal is a PITA to remove without it.

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Doing the Job
With all the parts and tools gathered, it's time to get to work. Perhaps obviously, the job is mostly a bunch of removal of parts, and then a bunch of installation of those same parts - or rather, installation of replacement parts. This list of steps is just that - a list of steps (which makes it a great resource to print off and reference when you're doing the job). If you're curious about what a step looks like, I suggest reading the story of my shop day, or watching this video to see how something is done.

For the full list of detailed, step-by-step instructions in a printable format, continue reading:

Step-by-Step Replacing Rear Axle Seal & Bearing w/ABS (1st gen Tacoma or 3rd gen 4Runner)






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Awesome write-up (as usual)... thx for sharing

 

Can vouch for this tool as well. Quality is top notch and it works extremely well. Looks like it now includes a 40mm bearing driver (wasn't in the kit when I brought it) which is awesome. If you don't have this part, you can use a galvanized pipe nipple or coupling from the hardware store. I think 1.5" SCH40 does the trick.

 

this is very thorough treatment for which i'm grateful. although I get to wondering if I'm grateful for this design from toyota. I can do the axle seal and bearings way easier on my GMC and Ford duallys. I understand you shouldn't have to do this often, but I've been doing wheel bearings for 40 years and not had one this complicated (maybe that's just luck and I should go find some wood to knock on).

As far as failure goes, ironically the bearing didn't fail, at least not fatally, it was still spinning nicely, but just not in the truck as the axle with the tire, wheel and drum started to walk out of my 2003 tacoma with 225,000 miles on the highway. fortunately I noticed what was going on in the rear view mirror when the back end started to swim around and pull over before I lost the whole thing on the road leading to who knows what kind of headaches for the traffic around me.

friend who has the tools to change the bearings speculated that c ring was left off at some previous service and the axle heated at some point and the pressed spacers got loose. I don't know, it was pretty exciting.

so I got the new bearing and seal pressed on the axle. not really sure if real axle oil even lubes the bearing in this case with all the pressed on spacers and seal riding on the spacer inside of the bearing, so one gets to wonder about the point of differential lube traveling down the axle housing in the first place, but maybe I'm missing something.

putting back together I notice a little more deviation in parallel of the mounting face of the axle housing and the brake backing plate with the 4 mounting studs. the picture is from the top with ABS sensor removed. you notice maybe not quite an eighth inch gap at the rear with the nuts made up hand tight. this doesn't change if i spin the axle to different orientations so I don't think it is indicative of a bent axle. the nuts will easily take the two mating surfaces flush with application of factory torque. It just occurs to me that this puts a tiny bit of angular load on the bearing. Is this kind of initial fit within the margins of error or is it indicative of a problem? thanks to OP or any later readers who can make an observation on this question.

thanks, Brian

PS didn't know about reversing the spacers or the sharpie line test for seal alignment. so I'm glad I haven't socked it down yet. i'll pull and check in accordance with this 'manual'.