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rear diff. removal and check

Discussion in 'Daihatsu Hi jet' started by fupabox, May 22, 2011.

  1. fupabox

    fupabox Well-Known Member

    I might as well make this into a rear diff removal how to ...since I'm doing it anyway.....About a week after replacing the rear pinion seal on my 1992 Hijet, I started to get a whining coming from what I'm sure was the rear end...the noise was worse on level ground constant speed,just barely touching the throttle...almost like a bad slave cylinder rattle/whine from a hydraulic clutch.....parked ..engine off,parking brake on,tranny in nuetral, 2wd ...grabbed the rear driveshaft and turned it manually back and forth...lots of slop..sounds almost as if it's coming from the transfer case...damn. doesn't look good...get it home ,drain the t-case and remove the rear driveshaft..once the driveshaft was separated from the t-case it was evident the clunking was coming from the rear diff and not the transfer case (pretty damn sure anyway:pop:)
    4 12mm bolts and slide the slip yoke from the t-case
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    this exposes the pinion nut...22mm i think?? bend the ears on the lock tab back before you can remove
    [​IMG]
    diff. input flange then comes right off with the seal runner and then the pinion seal
    [​IMG]
    Drain the rear diff fluid and put the truck on jackstands remove wheels...lube the crap out of the brake line flare-nuts because they ALL need to come off.
    remove the cotter pins and the rear axle nut 36mm...
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    Unhook the parking brake cables from inside the drums and undo all the brake hydraulic lines...then the 4 14mm nuts/bolts holding the brake backing plate/bearing retainer in
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    remove the rear backing plate and brake assembly as a unit
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    reinstall the axle washer and axle nut and using a slidehammer pull the axle straight out you can check the bearings and seals now the bearing has to be pressed off and on...my bearings were fine so I left them alone..as were the axle seals...
    [​IMG]
    once both sides are out remove the diff. carrier bolts (12mm) and pull out the carrier (prob have to tap around it,to loosen it from the axle housing)
    [​IMG]
    the pinion and ring gear teeth were all like new no visible wear whatsoever, but there was a lot of play in the pinion (about 2-3mm)
    [​IMG]


    cont'd.........
     
    Last edited: May 23, 2011
    Juju1187 likes this.
  2. fupabox

    fupabox Well-Known Member

    [​IMG]
    seems I lost a few pics ??? Hmmm...anyhow..the side bearing caps were removed from the diff.carrier and the differential removed...the pinion bearings were cleaned and re-lubed with 80-90 gear oil and the pinion gear and bearings reinstalled to see if they had been torqued properly...if not the pinion shims may need another few added...with a slight preload to seat the bearings the slop is gone from the pinion shaft....reinstalled the diff gears and found that by moving one of the side bearing shims to the other side..that left only .5mm of slop..... I'm also for some reason out of Permatex...no RTV nothing (has someone been shopping in my garage???) I will finish assembly and photos later this week......well not all of it...rain and friends with broken vehicles have bogged me down a bit........

    sealed and reinstalled rear diff carrier new pinion seal, pinion nut torqued to 30 lbft till axles installed
    [​IMG]
    [​IMG]

    clean the axle tube ends of old sealant and check condition of axle seals....
    [​IMG]

    clean the axle and bearing then coat the entire thing lightly with diff fluid....gently insert the axle into the tube ...when you are sure the splines are mating up with the diff. tap it home with a hammer..it should go in smoothly with fairly light taps ....
    [​IMG]
    [​IMG]

    apply sealant to the rear of the brake backing plates and reinstall the 4 nuts/bolts....hook up the parking brake cables and re-attach the brake lines..bolt on the drums...axle nuts temp. tightened to retain the drums
    [​IMG]
    [​IMG]

    remove the lid from the brake fluid reservoir and fill with dot4 or better.
    [​IMG]

    from the passenger side bleed the rear brake lines (unlike most cars with a bleeder on each corner.. the rear on the Hijet is 1 single line going into the drivers side wheel cylinder..exiting to the passenger side through another line and ending the circuit at the bleeder nipple)....this makes bleeding a bit less of a hassle unless you step on and break your vacuum pump...
    [​IMG]


    Still not complete but the weather isn't co-operating
     
    Last edited: May 25, 2011
  3. fupabox

    fupabox Well-Known Member

    OK ...time to put this sucker to bed...get someone to hold the brake pedal down and torque the axle nuts to 145-175 lbft...line up the cotter pin hole in the castle nut,but only tighten to line it up ...now you can reinstall rims tires..refill the rear diff with 80-90
    [​IMG]

    lower the truck onto the wheels and get your helper to apply brakes again so you can torque pinion nut to 75-95 lbft you can do it yourself if you have a torque adjustable impact gun...don't forget the locking tab that installs behind the nut,and then is hammered in to lock the nut....raise the truck again and rotate the rear diff by hand again to be sure the bearings are seated ..rotate 10-20 rotations to be sure..then rotate 10-20 in the opposite direction...and recheck torque....bend retainer flaps into place....reinstall the rear driveshaft
    [​IMG]

    Bobs yer uncle (maybe he is...prob. not:p)....time for a test drive
     
    Last edited: Jun 1, 2011
    Juju1187 likes this.
  4. erixun

    erixun Member

    Nice post, your internals look to be ok, (atleast in the photo's) I will be interested if this ceases your whining.:D :pop: Keep in coming...
     
  5. fupabox

    fupabox Well-Known Member

    It must be me ,but I just can't seem to take a clear picture anymore...no matter what camera I'm using:confused:
     
  6. starpuss

    starpuss Member

    your diff looks to be in good shape. i bet you the whining is from the tcase
     
  7. fupabox

    fupabox Well-Known Member

    Hope not....The pinion had a bit too much play and the ring gear was over-shimmed to one side...so I'm praying that's it....If it's a bearing or something in the t-case, I would doubt the part is available
     
  8. Ironraven

    Ironraven Active Member

    You're holding the camera too close, that's why they never focus. You can always crop the pics on your machine afterwords, most cameras these days take pics that are 100x bigger than they need to be anyway...

    Nice work though, I vote for a sticky!!!
     
  9. BigJoel

    BigJoel Member

    If it comes to this, do yall have a place that can measure the bearing and look for a replacement by size? Some are more common than you would think.
     
  10. fupabox

    fupabox Well-Known Member

    If it is I will do my damndest to find a replacement....I can't stand not being able to repair something ...replacement is only the last option:D
     
  11. fupabox

    fupabox Well-Known Member

    Well the whining /grinding is still there.....so out comes the transfer case and tranny:frustration: the backlash in the rear end is gone but it seems that had nothing to do with the noise...odd cause it seemed to be an over-run gear sound
     
    Last edited: May 31, 2011
  12. BigJoel

    BigJoel Member

    I'm having a similar problem to yours fupa. It get my noise (and a vibration) only when under power though, and more so when under a load. It get's worse when i am pulling a hill or when i accelerate, but it's not even noticeable when cruising along. Any idea what mine may be?
     
  13. fupabox

    fupabox Well-Known Member

    Actually I'm happy to report the noise is now gone.....I had no choice but to take the hijet because I have to mow 3 lawns today....I jacked the rear end up and put it in gear..the noise again seemed to be coming from the diff???...I then put it in reverse for a few minutes (not really sure why ??) I grabbed the rear driveshaft and noticed an absolute ton of backlash/play in the rear diff again:confused::frustration:...removed the rear shaft again (I just put $20 worth of synthetic in the t-case so I jacked it up REAL high so I wouldn't lose much...I'm part Scottish what can I say:eek:)

    The pinion nut was loose...hmm..I had marked the nut and retainer with a paint stick out of habit and they hadn't moved...retorqued to 60lbft and put the driveshaft back in ...ran through all the gears and reverse each for about a minute and rechecked the torque...still good and no play....shaft back in and no noise......From what I can surmise the sound was the loose pinion bearing the first time,and then when I re-installed the bearing never seated properly...as you can see in my write up I spun the diff about 20 rotations to be sure it seated..should have done it in both directions ....Noise gone BYE BYE:D.....I will edit the write up to include seating the bearing in both directions, can't hurt
     
    Juju1187 and Afromus Prime like this.
  14. Juju1187

    Juju1187 New Member

    Do you recall if you needed to replace the pinon nut or just reused the old one?

    TIA
     
  15. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    The nut should be reusable, unless the shoulders are rounded. Not sure if the diffs have a crush sleeve which would not be reusable.

    Looking at Fupa’s write up: I was trained to put the wheel on and rotate the wheel as I bring up the torque to get things centered up. I torque the axle nut while spinning the wheel until I hit the max torque, then back off just enough to install the cotter pin.
     
    Juju1187 and Limestone like this.
  16. bobjonah

    bobjonah Active Member

    Great tip regarding seating the pinion bearing. I just replaced one bearing and re shimmed everything - but still have a hatefull Jing / Jing when coasting between acceleration and decelleration. I will try retorqueing the pinion shaft as suggested.
    Note that all bearings have a number , and can be matched across different manufacturers. I had no trouble getting the proper bearing from Canadian Bearing Supply. Seals are another matter, as different dust seals and protectors make them hard to cross reference - measurement is often necessary - best to be carefull and not tear them.
     

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