Diff Grinding Bad-Any suggestions for a HEAVIER OIL & OR ADDITIVE to EXTEND life?

Discussion in 'General Chevy & GM Tech Questions' started by themexicandoctor, Dec 30, 2010.

  1. themexicandoctor

    themexicandoctor New Member

    Everyone has been very helpful here.

    Have a 1999 GMC 1500 Savana with a Conversion Van Body and a recently replaced 460 Tranny with a Jasper Unit.

    Bottom line; the noise from my differential is incredible, its only a matter of time before it blows like my Transmission did.

    I spoke to a mechanic today and maybe he was joking but he said there is a product that Pep Boys sells called "Molasses" or something like that which is very heavy diff oil and acts to get rid of the noise and extend the differential/axle life, he says for saome people he puts it in and they never have to replace the axle/diff.

    Is he BSing me?

    Or is there such a product and do any of you recommend it.

    Or is there any other product you suggest, that would work - I need to extend the life of this differential for as long as I can.

    Whatever you guys suggest, I will do it (apart from rushing out and buying a new diff because according to my regular mechanic, its no different from the tranny, when it blows, replace it then as it wont do any damage to the rest of the vehicle).

    Thank you!
  2. themexicandoctor

    themexicandoctor New Member

    PS. I has New U Joints, Shocks, Brakes, etc - my mechanic does say its ...

    The rear Axle/Diff that needs to be replaced.

    But again, any suggestions as to the veracity of "molasses brand or name" that is available or any recommendations for a heavier oil not for the noise but to make the axle run for much longer until it explodes
  3. stephan

    stephan Rockstar 4 Years 5000 Posts

    The stuff he's talking about will quiet them down if they aren't hurt too bad already, but won't make it last longer. The best thing to do is stop driving it till you can fix it. The bearings usually go first & if you catch it fast enough you won't destroy the ring & pinion. Usually the only way the ring & pinion start going out first, is from continuous abuse like 5,000 RPM burnouts, or going off 4 foot jumps, having the drivetrain freewheeling & then getting the inertia stop when landing. Either of these will shed the teeth off the gears. Your gears may survive & your repair bill will be a lot lower, if you address this now.

    DAREDEVIL Rockstar 4 Years 1000 Posts

    Get it flushed thru and then stick some bananas in there with the oil....but u need to fix it sooner or later !
  5. themexicandoctor

    themexicandoctor New Member

    Stefan & Daredevil - Thank you - I cannot afford to keep pouring money into this truck, just last week because of the rain in California, and my radiator went the same day as my power steering pump together with haveing to reupholster the entire truck because of the leak, I invested another $1600 into a truck I am trying to save for another, new. This truck sucks me dry everytime I get cash to save.

    Question 1 - what is the name of the product/s you recommend?

    Is Lucas a good choice or is there something better?

    2. I was under the impression I could drive it till it blew and then simply buying a used axle from a wrecker and everything would be used, but with a guarantee, in good condition - if I drive it and it breaks, is the rack and pinion part of the new (from a junk yard) or is this something separate that I have to buy or repair?
  6. stephan

    stephan Rockstar 4 Years 5000 Posts

    LOL...Yeah Scotty, I saw that on the Gomer Pyle show about 10 years ago. Sure you can stuff banannas or sawdust in there with some 500 weight grease, but it's going to ruin every other part in the process.
    Is that how you would repair your mothers car?? ha ha ha
  7. themexicandoctor

    themexicandoctor New Member

    If my Mother wanted to stop throwing money away

    On a vehicle she would rather drive till it drops, I would.

    On a serious note can you guys answer those questions as to

    the name of your recommendations

    and if I am planning on buying a whole axle/new* diff anyway from a junk dealer anyway with a warranty, do I need to worry about damaging the pinion, etc or is it included in the junkyard special.

    My mechanic says he can pick one up for about $300 whereas a new remanufactured transmission from Jasper, (who are the best), is about $1800-2000

    Thank you!

    DAREDEVIL Rockstar 4 Years 1000 Posts

    #1 for now would do..but also there is stuff out there i heard of that wroks real well.
    Option #2 will be ok, and the ring and pinion should be incl !!
  9. stephan

    stephan Rockstar 4 Years 5000 Posts

    OK Doc, I just want to make sure you understand that none of those expensive additives will extend the life of your rear end because of the point that it has gotten to.
    There are additives that might make it quieter.
    If this is what you wish, then just go buy the thickest & cheapest stuff you can find to put in there. If they sell "Power Punch" in your area buy it. It's the cheapest they sell here. It's like STP. Or you can try the Molasses stuff that your friend recommended.
    I just want you to understand that there aren't any magic fluids that will make it last longer because of the condition that it's in now. Those longevity fluids are meant to be used before any damage has occoured. Repairing it is the only thing that will make it last longer now.
  10. themexicandoctor

    themexicandoctor New Member

    Thank You, Thank You!

    I hear what you guys are saying, if it worked that well I would have poured it in my exgirlfriend - just want a couple more months hopefully before dropping another $1000.

    Again, thank you very much - I did use the Lucas transmission stuff when I thought my tranny* was going to explode about 3 months after it went bad at the halfway point of a long trip (it would occassionally lock up and not move) and the tranny lasted another 6-9 months before it went out.

    *not the same girlfriend

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