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Possible drive shaft angle misalignment

Discussion in 'General Truck Info' started by allochris, Aug 19, 2022.

  1. allochris

    allochris New Member

    2005 Da63t, recently heavily modified with GRImport 4" front suspension drop blocks & 3" wedge shape rear blocks mounted over rear axle. Rear leaf packs also modified with 1 extra set of mini4x4.ca add-a-leaf springs. Over all rear axle is now much lower than stock in relation to the stock ride height ~4", enough that I made a 1" driveshaft Al spacer to go between driveshaft and rear diff., to prevent the driveshaft from possibly dropping off the transfer case output splined hole.

    Since the lift was installed, dry spinning horrible bearing noise started when traveling beyond ~50km/hr all the way to max speed, in gear or in neutral, both during coasting, acceleration and deceleration. Below ~50km/hr, noise is not noticeable.

    I notice that my u joint driveshaft driveline input and output angles aren't the same, b/c the wedge block in the rear axle housing tilts the pinion up towards the transfer case, but the output angle of the transfer case remains the same at stock angle: pretty much horizontal.

    I feel no vibration when hearing the horrible constant dry bearing noise. Reading a few littérature in torsional vibration caused by mismatched driveline angles (when input and output u joint angles are not in phase to cancel out the rotational force, is that my possible start of problem(s)?

    I also notice my pinion seal just also started to seep oil to wet the outside of diff housing.

    any recommendations?

    I.e. make a custom transfer case top lowering mount to tilt the transfer case output angle downward to parallel /match the diff pinion input angle?
     
  2. allochris

    allochris New Member

    Well, today I experimented with taking off the rear drive shaft to go for a spin in fwd. Not even 10mins in, I started to hear a new seal like noise from underneath the box area. Stopped to check and it turns out gear oil is leaking out of the rear output seal!

    I think it is actually good news that I finally located the source of my horrible bearing noise when traveling 50km/hr and over.

    Just before my test drive, I also measured my driveline angles. It is as follows:

    Transfer case - Driveshaft: 11.3° (idéal is <3°)
    Driveshaft - Pinion: 5.8° (idéal is <3°)
    Transfer case - Pinion: 5.5° (idéal is <1°)

    my theory: As my driveline angles were way out of specs, it caused unbalanced force on both transfer case output seal and rear diff pinion, slowly destroying them in the process.

    Now I have to study the service manual to figure out how to change that rear seal and bearing on the transfer case. While I'm doing that, I will also need to shim/lower the rear transfer case mount to reduce my excessive driveline angle, and to parallel match the rear pinion angle.

    Hopefully when it is all said and done, I won't experience the same problem again...

    Any suggestions out there?
     
    Last edited: Aug 21, 2022
  3. fmartin_gila

    fmartin_gila Active Member

    Ah-yes, the consequences of exceeding the designed operating parameters. Consider that if you lower the rear mount, it will raise the front of the engine as the front mounts will be the pivot point, thus putting stress on the coolant hoses, which may create other problems which will have to be addressed. The shift cables may also be stressed/stretched somewhat. The operating angles of the driveshaft joints do need to be within 1/2 degree of each other to ensure harmonic balance. If the pinion seal is showing weeping, that is an indication that the input bearing of the diff has possibly a bit too much play allowing the shaft to vibrate a bit and may need to be retorqued or bearing renewal, depending on how it is set up. U joints can only be so far out of a straight plane when they will hit "lock-up" at which point the machined surface will start to flatten the seal beyond the amount of flex designed for. You might do some searching at a driveline shop to see if there is possibly some different U joints with a deeper "U" and designed for a sharper operating angle that you could use and make up a whole driveline. Consider Cardan type double joints as used in the big Lincoln (1970s) drivelines to ensure smooth operation or the older (1940/50s)Chrysler Corp ball &roller type joints. Could you possibly get by with a bit less lift or is it required for some reason.

    Fred

    Just things to consider and food for thought.
     
    Last edited: Aug 21, 2022
  4. Bill Johnson

    Bill Johnson New Member

    Interesting post. I appreciate it though much of it is beyond my expertise.

    here is a question you might be able to help me with.

    My vehicle is a new 2021 Daihatsu hijet purchased from an importer in Michigan. Before shipping to me, they performed a lift and changed the tires to off road tires. I have since switched back to stock tires.

    I hear a terrible grind sound in 4th and 5th gear when I let off the gas, especially >50 mph. Nothing in 1-3.

    Do you think I have a leak and I’d so how can I check or replenish? Do you think the angles are off because of the lift performed? Could I perhaps reverse or limit the lift and improve the situation? Have I done permanent damage by driving like this for 200k?

    thank you
     
  5. allochris

    allochris New Member

    Hi, mine also started making grinding noise at 50km/hr+, no matter in which gear or neutral, on gas pedal or not.

    Here is what I would start to do isolate the grinding sound to pinpoint exactly where it's coming from. I would remove the rear shaft completely, then drive around in 4hi (basically front wheel drive), and play with coasting in neutral or in gears at the speed you normally hear abnormal sounds. If the sound persists or go away, then that should help locating the sound origin. When I did the same thing last week, my transfer case output seal failed while doing so...So hopefully u'll have more luck than I did!

    Measure your driveline angle, as well as yr t-case and pinion angle while you are down under. Download the TREMEC app from your app store to measure the angles with yr phone. Remember to grab a marker to mark the position of the shaft against pinion & t-case before dissemble, that will prevent you from re-installing 90 or 180 out of phase.

    There are tons of driveline angle videos on YouTube you can read up on, to see what the max angles should be to bring it back close to stock

    Good luck!
     
    Last edited: Aug 25, 2022
  6. allochris

    allochris New Member

    Update: So I have taken things apart to find the source of my grinding bearing noise.

    This #18 needle roller bearing (based on Fig.291F from Megazip.net My Da63T is a KKCJ-SP5) is located at the readend of the main shaft and it nests inside the front end of the TC output shaft #8.

    I can wiggle the bearing radially, axially, and tilting it diagonally with surprisingly more play than I would expect. If I push it forward against the mainshaft and spin by fingers it feels ok, but not perfectly smooth. That needle bearing size is supposed to be 17x22x15.8 & that's what I also measured with my caliper. I haven't yet measure the ID of the TC output shaft #8 (or the OD of the main shaft since I haven't taken the bearing off yet). I am suspecting (hopefully not) all that finly grinded metal and collected at the magnetic drain plug could be originated from the mainshaft. I can definitely find evidence of the same fine metal dust inside the cavity of the TC output shaft #8. Could that be it?
    [​IMG]

    here is a link to my video:


    I've came across this video on youtube, I wonder if my problem is somewhat similar to this one:


    Chris
     
  7. allochris

    allochris New Member

    So I diagnosed further with 2 other's set of eyes today. We came up with a theory that originally caused this bearing noise. We think it is caused by overloading the truck bed (before the lift) with heavy cargo thus putting the rear springs into the reverse arch position. The stock rubber bump stops were very close to the frame, so driving over bumps in motion with the heavy load would definitely max out the downtravel of the rear suspension. It is when this occurs, the female slip yoke of driveshaft get maxed out and contacted against the male end of the rear transfer case output shaft. All that force pushed against the transfer output shaft translated to shock loading 1 of the two main bearings (#22 & #17) that secure the transfer output shaft to the transfer case.

    Additionally, the front of the transfer shaft then pushes against the roller bearing #18 that rides on the very end of the main shaft, thus getting its grinding treatment on its lip pushing against the splined main shaft.

    I have yet to inspect the rear diff. Hopefully this same force didn't also damage the pinion bearing by shock loading (force pushing into the diff )

    I'll post photos next.
     

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