My ZUK Story: Rear Diff Rebuild Stops the Whine

Discussion in '80-Series Tech' started by melmwood, Aug 10, 2018.

  1. melmwood

    melmwood SILVER Star

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    About five months of ownership under my belt now, and the number one concern and issue I had with my 97 FZJ80 w/ 171k is finally resolved: the whine is gone. Let me explain...

    I've spent the last five months trying to internet-diagnose all the possible sources of my LC's whine on acceleration (and slight on decel). This whine nearly drove me to steer into a bridge column during her maiden voyage from CA to MN this March. When on the gas, it was steady and noisy and encapsulated the entire cabin (which made it very hard to pinpoint the source). As soon as your foot was off, it was gone. Loudest from 40-60mph, but audible no matter the speed. I read every IH8 forum post I could on "whining" and such noises, finding too many potential/suggested causes and often seeing threads die with the OP never coming back to say what they ever discovered.

    So I called my local mechanic buddy finally fed up not knowing. We did a test drive, and he immediately said the whine was likely the rear diff bearings just going bad. We got back to the shop, he put it on the lift, ran it, and said it was definitely coming from the rear diff, which is usually always just the bearings. So then I did what you're supposed to do - I came here and searched everything rear diff related. And one thing kept popping up: ZUK.

    It seemed odd that everyone took off their rear diff and mailed it to a guy in AZ, even for just bearings. But the more I read, and the more details and photos I saw in each ZUK post, I started figuring it out. And then I saw his site - gearinstalls.com - and I knew he was my guy. While I assumed it would be just the bearings, I also thought, "What if it's the gears?" My buddy isn't an LC specialist by any means, and although I trust him, I don't think he'd have the same care and precision showcased by ZUK (aka Ken Francisco) on his website with all the custom shims and paint tests. So I contacted ZUK and he was awesome to communicate with via email. Very fast replies. Very detailed. Very patient.

    He told me all the costs and we got a timetable setup that worked perfect - I mean, being without my LC for two weeks isn't perfect, but I could make do without it. For some, this is may be a dealbreaker due to primary vehicle and all. I'm happy I could make it work and let ZUK do the work. *Note: could have been faster had I paid more for faster shipping than just Ground.

    I took my rear diff off on Monday, July 30th. Mailed it FedEx Ground to ZUK in AZ. It arrived Friday, August 3rd. He worked on it over the weekend, and communicated via email w/ me several times. Gave me tons of pictures, and explained everything. My bearings were loose, but all were actually in good condition (along with the races). His paint test on my gears showed some erratic patterns. This, coupled with the decent bearings and races, made ZUK think the best option to ensure the whine was killed for good would be to swap out the gears for a solid used set he had in his shop from a '96. Price was more than fair, and I felt good about all of it getting done in one shot. He sent new pics of the paint test with the swapped gears on my diff, and it all looked perfect.

    He got it mailed back out on Monday, August 6th. Today, August 10th, it arrived right on schedule and once I got her all buttoned up, not a single whine was heard. For five months I was driving myself mad trying to identify the whine. And it was driving me mad every time I heard it. I am thankful the forums led me to ZUK. And I couldn't be happier that I can now say ZUK has worked on my rig.

    I didn't document my portions of dropping and re-installing as the forums have plenty of footage on those jobs already. I'll just say this: the cone washers on the axles suck. I skipped the whole "pound with a brass drift" step to remove them and found that skipping to next step where you have to screw two long (M8 size if memory serves...get some 4"+ in length) bolts into the axel hub plate to "press" the axel out works fine. Screw them in to press the hub out just a bit, then unscrew them and press the hub back in. They'll be loose and easy to grab now (unsure if this is a no-no for some, but it was a breeze and issue free for me). Here are some pics from ZUK of my job, just to add some visuals...

     
    Lumpskie, Tuite, rockstate45 and 5 others like this.
  2. Laisser aller

    Laisser aller

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    Old-timers just seem to know how to do it better. Glad this widely fabled artist signs his work.

    I am not sorry your gears went... because you obviously lend value somewhere that is not so easily seen.

    Best thread I have read all week.

    Thanks melmwood.
     
    Last edited: Aug 11, 2018
    icorradoi and rockstate45 like this.
  3. 80t0ylc

    80t0ylc Hill & Gully Rider

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    Melmwood, looks like you're another joyfully satisfied customer of Ken Francisco (Zuk). Ken considers "above and beyond" as a standard business practice. That is why his customers keep coming back. Anyone that knows high quality and wants differential work done, and done right the 1st time, takes it to Ken. He rebuilt both diff's on my '94 80 series including new ring & pinions with Harrop e-lockers. My initial symptom was a leaking rear pinion seal, but I wanted to make maximum advantage of tearing into, what started as just the rear diff. From the mods I have done and added weight, I needed to re-gear and as we all know, regear on a 4WD rig requires both diffs re-geared. My 80 originally came with open diffs and I wanted e-lockers so this was the perfect opportunity. A long time ago, I'd picked Ken to do this job in my research, if I ever were to get it done. It was a pleasure working with him to get it done. As busy as he was, he managed to get my diffs done on my schedule, plus I had a great visit to his shop in Chandler. He is a real treasure to the Toyota off road community. A toast to Zuk, :cheers:
     
  4. Cruiserdrew

    Cruiserdrew On the way there SILVER Star

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    Agree, Zuk is awesome. If you want your differential work done right, he is the guy. I have 5 differentials from him, and will have at least 1 more in the future. I even got to meet the gentleman himself which was a real pleasure. I keep 2 spare Heavy Duty boxes in the garage just for sending differentials to Ken!
     
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  5. icorradoi

    icorradoi SILVER Star

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    Zuk is the man! Glad he got you straightened out. He installed 4.88's in my '96. Hmmm...I wonder who's original gear set you received?
     
  6. vegasfj40

    vegasfj40

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    ZUK is the man!! I sent him the rear diff in my 85 pickup a couple of years ago and had him rebuild with 4.56 gears and it's been flawless and quiet. Price was very good too. Next time I need any diff work on my Toyotas I will be sending it to him. .
     
  7. excessive

    excessive

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    ZUK redid my front diff a few months ago, he's not cheap - but I have no worries the work is done right.
     
  8. Heckraiser

    Heckraiser

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    Still amazed that ZUK has been at it so long (since back in my mini-truck days, before I ever owned ANY land cruiser) and still does it well enough to garner a random shout out thread from a new customer. :beer:
     
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