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diff pinion bearings and expansion valve

Discussion in '80-Series Tech' started by AZcruiser, Jul 1, 2003.

  1. AZcruiser

    AZcruiser

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    I took my cruiser to a local shop - non Toyota to save me $85. The reason to pinpoint the high pitched hum and low speed grinding, his input was 'rear pinion bearing'. The only bearing I know of is the wheel bearings on semi-floater axel.
    Also my belts have been needing changing, they whistle. A little WD-40 quiets them up for a short time. The mechanic says its an 'expansion valve', no specifics yet but wanted to get this out to real experts to get your input.
    Any thoughts, especially regarding the expansion valve...

    much thanks to all
    C
     
  2. Big_Moose

    Big_Moose

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    The Semi-floating axle has 2-axle bearings (outer most section of the tube), 2-differential carrier bearings, and 2-pinion bearings.

    The Full floating axle has 4-wheel bearings (2 per side / similar to the front axle), 2-differential carrier bearings, and 2 pinion bearings.

    Wear the companion flange / differential flange enters the differential housing just past the seal, there is a tapered roller bearing - the outer (most common to fail) pinion bearing. There is another tapered roller bearing on the pinion shaft just before the pinion gear, this one is a *&^% to remove, and generally doesn't fail as often. The preload between these two bearings controls the "depth" of the pinion gear (thinking front of diff to back cover line of direction) in a simplistic description.

    So yes, High speed whine could be orginating from the outer pinion bearings. If the bearings are worn, the pinion can wobble / move fore-aft, and cause the whine. Mechanic should be able to test the flange / driveshaft for bearing wear / play.

    "Expansion valve", does he mean some type of "tensioner" in the belt path. Don't specifically know if FZJ/FJ80 use this to maintain belt tension.

    Will defer to others, Wulf, CDan.......

    Joe
     
  3. AZcruiser

    AZcruiser

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    I just spoke to him, the expansion valve hes saying is in the right side of dash which is part of the A/C system. Thinking its a 'tube' clogged and with fluid which can cause damage back at the A/C compressor...quoting $400. This is a concern to me, in AZ A/C is about as important than the 4 wheels driving the vehicle!!
    Looking at a rear axel diagram, it looks like the pinion bearings/seal are accessible by rear diff vs through the axel. From our convers. it sounded like it is the outer vs inner, but really cant tell w/o tearing it apart..wanting $800 I have sources to do this myself - I hope.

    Thanks
     
  4. Big_Moose

    Big_Moose

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    Ok with you now :D, thought we were talking about the slipping belts. Expansion valve is one of the critical components in the AC system. E-valve is used to regulate the transition from liquid refrigerant to a gaseous state. Generally, they become clogged from condensation freezing in the expansion valve. I hate AC work, understand the gravity of no AC in AZ, so can't help with the issue - maybe Cdan can qoute part prices?

    Yes, to get to the pinion bearing you will have to remove the differential. Remove the axles, brakes, etc., then remove the carrier, then the carrier, then the bearings (outer in the housing & inner on the shaft), and then reassemble / adjust backlash, and install diff back in truck.

    If you have a dial indicator / method to measure backlash, you can replace the pinion bearing yourself. Now, since you are in there - common sense tells you to replace the inner pinion bearing. The problem is that this bearing requires a special puller or machine shop press to remove. Other then that bearing issue the rebuild job is really not that difficult.

    You could also pull the differential yourself, and take it to your mechanic for the repair, and then you install it in the truck. Should knock a couple of hours / bucks off the qouted price.

    Joe
     
  5. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    What year is the vehicle? ???
     
  6. AZcruiser

    AZcruiser

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    94 w/ center locker.

    Its a real bitch, money that has to go to repairs and not the fun stuff, Kaymar, Slee toys,etc.
    I did some checking on my lunch break and pulled a diagram from a CD manual, to get to the expansion valve the system has to be discharged, but looks fairly easy to get to(under the dash). And I am assuming the work to be done is to clean it out. The sound is a hiss when the A/C is on. By the way the belts do squeek/whistle but I guess its much more.
    Interesting thoughts about tearing the diff down and taking it in. This could also take care of the "clunk" thats been going on for a while, but seems like everyone has it, but mine is worse??? because no one else seems to get this high pitched hum at high speeds.

    C
     
  7. landtoy80

    landtoy80

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    I get a low hum that pulsates at 70ish mph. I rebuilt the front diff, and new t-case , u-joints and it is still there. The rear diff will be this fall maybe.
    kurt
     
  8. Seminole

    Seminole

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    8) Chiming in about your problems.
    1.) I just went through the A/C in my 91. Sounds like they are trying to stiff you for the entire evaporator assembly(400.00). The expansion valve on it's own is about 65.00?(C-Dan is the expert). You CAN just replace the expansion valve and not the evap. assy./core, if it is leaking. If you have to replace it, I suggest you replace the drier too (+/- 70.00) and the various o-rings from opening the lines. IT HAS TO BE PUMPED DOWN UNDER VACUUM to do this and to recharge the system properly. I would also suggest that you do not take their word for it regarding a leak, ask to have the mech./tech show you the leak with either a "sniffer"(tech term) or the uv light. If it does have a leak, they'll have nothing to hide. I am not really an expert but have the benefit of the following:
    a. living in Central FL all my civillian life
    b. just having done this with mine
    c. my Dad was an A/C contractor for 30 yrs and still has all the equipment to test and repair.

    2.) Just did(last week) the front pinion seal on the FR diff. I checked the RR(?)(closest to the seal)bearing when I was in there. That one you don't have to remove the diff to replace, but you do need about three pullers to do it. No whining, but the stench of 90wt was powerful. Local stealer quotes about 275.00 to replace seal and rr pinion bearing.

    Hope any of this helps. :-/
     
  9. Photoman

    Photoman SILVER Star

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    Az,
    This may be irrelevant but if your belts are slipping that much maybe the AC compressor isn't being driven hard enough if the belt is slipping.
    Bill
     
  10. AZcruiser

    AZcruiser

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    Seminole, what part of central Fl? I grew up in Jax but ended up in AZ.
    I just had a (cruiserpart rebuilt)compressor put on by a shop last month. Most shops wouldnt do it but with all said, they probably didnt do any extra i.e. cleanout the expansion valve,etc. Does all this result back to the newer compresoor added, they also put on a new drier. But I do agree the system has to be discharged to get to the valve. I plan to changeout the belts this weekend, first to see where this goes. Great info on the pinion bearing/seal. Do you have access to the p/ns or did you source through a Toyota parts person? Was it a difficult job besides using the pullers to remove. Waiting for C-Dan to chime in..
    Thanks for the great input

    C
     
  11. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    Wow, where to start.

    I was up to my a** in aligators today and this is the first chance I've had to ponder. Expansion valves are picky critters. Yours may have ingested something it didn't like. It has been my experience that if one is fouled or otherwise unhappy it is best to toss it and start fresh. Replacement of said item requires opening up the system and removal of the evaporator assembly from the passenger compartment. The evaporator then needs to be taken apart to access the coil and lines. Often some of the line fittings get damaged in the process requiring additional replacement parts. After re-assembly the sytem requires an evacuation and a re-charge of the appropriate refrigerant. As I have escaped from work and am lounging at home (sipping a Keystone, of course) I do not have an absolute Dollar number for you. IIRC the expansion valve is indeed around 60 bucks. The job is labor intensive, therefore expensive.
    Re the axle, I need more information before I care to speculate on what is going on there. IF it happens to be a pinion bearing, it is possible to replace the outer pinion bearing without removing the diff. It is very difficult and I would not attempt it. If it is the inner bearing or anything else associated with the diff, it will have to be removed and addressed.
    Please tell more about the "noise"

    Regards, Dan
     
  12. Beowulf

    Beowulf

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    AZ,

    >> This may be irrelevant but if your belts are slipping <<
    >> that much maybe the AC compressor isn't being <<
    >> driven hard enough if the belt is slipping. <<
    >> Bill <<

    Please replace the belts first. What Bill said is exactly what happened to mine 2 weeks after I bought it. I was prepared for a big $$$ repair and the initial diagnosis was the expansion valve. We decided to put on new belts; they were not making noise but were slipping upon visual inspection.

    Bottom line: Replaced all belts and 2 years later the coooooold air is still pumping. Knock wood.

    -B-
     
  13. AZcruiser

    AZcruiser

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    Beowulf-
    Thats the plan to change the belts first. There is no noise related to the EV in or near the cab.
    C-Dan-
    The noise at low speeds is a grinding/winding up sound. Of course this drowns out the faster, at 55-70mph a high pitched hum echoes through the cab, hit about 80 it goes away. I also noticed vibration too at mid speeds too.
    For some time now I have had the 'thud' after letting out brake and the 'clunk' say letting off the gas around 30.


    C
     
  14. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    What kind of tires (ok TYRES) are you running?
     
  15. landtoy80

    landtoy80

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    the 'clunk' say letting off the gas around 30.

    I have that too. When in second gear and let off the gas. It clunks into first.
    kurt
     
  16. AZcruiser

    AZcruiser

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    Stock- LTX Mich's for now - repairs are keeping me from scratching off items from my kaymar and slee toy list!
    I was thinking of rotating them first to see if the hum noise goes away.
    C
     
  17. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    The reason for the tire question was to determine if you had agressive tires that were worn. Sometimes they can do funny things that folks blame on drivetrain. It doesn't seem likely in your case.
     
  18. AZcruiser

    AZcruiser

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    Also - I see there is a 2 pinion and 4 pinion rear diff. is this to do with full and semi float axels?
    C