Jump to content

Grinding /roaring noise in 2hi

raindancer

Recommended Posts

raindancer New Member

raindancer

Posted
Posted

my 1995 GMC Z71 is making a grinding noise on acceleration in 2hi only. I've drained & replaced all drive train fluids, everything looked clean. whats my next step? The truck has a 350, 5 speed granny low, with an NP241-c transfer case.

DaveH71 Enthusiast

DaveH71

Posted
Posted

Common problem with those transfer cases, there is a lock ring on the output shaft of the transfer case. This lock ring breaks and lets the gears mash together inside the case. Pull the rear drive shaft and then pull the tail housing on the back of the transfer case and you will be able to see it.

 

2010-11-07_203008_snap.gif

 

There was a permanent fix developed for this awhile ago but i haven't seen one of these transfer cases in awhile so you might wanna see what you can find on google, or just replace it with another stock part. If you can don't drive the truck because if this is the problem it will cause damage. At least drive it the least amount possible.

raindancer New Member

raindancer

Posted
  • Author
Posted

I'll take it apart tomorrow & have a look. I have a t-case & front & rear end to go on it but I wanted to wait till after deer season to tear it all down. this points me where to go next, I appreciate it! I'll post to let you know what I find.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • Newduramaxh*ar
      DTC P2C48 auxiliary cooling pump

      By Newduramaxh*ar · Posted

      I tried tapping it.  This might sound like a dumb question, you should feel vibration or some type of noise when it turns on? Can someone please verify? Thank you all!
    • Chuck FB
      first oil change - 2026 2500HD gas

      By Chuck FB · Posted

      I feel better now for my own view point and actions or lack there of towards the dealership service theme reading your post and others. GM corporate is who offers the two free oil changes on the HD trucks and I bought my truck in Feb of 2025 and those oil change offers run out within 2 years I believe and I highly doubt I will be using either one of them. I had asked if I could officially give those free services to another customer ( a friend ) and they said no, its all a GM corporate thing based on the vehicle in question. What that service advisor did however was go into a little story about how such and such customer was denied engine warranty because he had done his own oil changes because then they are not documented ... you see where that goes and so an employee playing the game of scaring the customer into having the service work done there most certainly triggered my thought process. At a later date I did talk to the person who handles warranty claims at the dealership and she said to be sure to document the oil changes and keep receipts for the oil and filter ( coped the receipts from cases of Mobil oil and case of filters I bought from them ) and the vehicles VIN, the date of service, mileage etc and staple that together as a record I would give them if that was ever needed and I keep my own log book for services for each vehicle as well. Oh and about 8 months after I bought the truck the dealer starts calling me to offer a maintenance service since they haven't seen my vehicle show up on their system ... for the mere fee of 300.00 Canadian to change the oil and rotate the tires and a few other minor checks and I declined the offer, I get the call again a couple of months later for the same thing and she could tell I was not interested and she asked if they should take my name off the call list and I said yes, do that !.    By the way did you happen to keep your factory oil filter to open it up and see the surprises inside as I expect some will show up as per the odd little sliver of metal shaving and particles that the filter does trap along with bits of grey silicone sealer that come off of the inside edge of mating surfaces. I have cut open every filter so far on my truck although few miles but have changed the oil often and the second filter was vastly better with very little of anything, that first filter was the unsettling one as I expected it would be. 
    • OnTheReel
      OCI, not when but why?

      By OnTheReel · Posted

      I get why they do this…but man…not ideal. I only extract on inboard boat engines because the drains are buried and even then I hate it because it’s easy to leave a quart behind with that method.   They should market it as an “oil refresh” not oil change!
    • KARNUT
      OCI, not when but why?

      By KARNUT · Posted

      I only get oil changed where I can watch. Valvoline pulls through the dipstick into a see thru glass. When done they show me the dipstick. About the only way they can mess up is using the wrong oil. But that secret wouldn’t stay secret long. Honda uses TQ wrenches on everything. You can watch through a plate glass window. Discount tires does that with tires. Trust but verify. 
    • Grumpy Bear
      OCI, not when but why?

      By Grumpy Bear · Posted

      I would not argue that with you. It would be pointless to argue against the truth and you speak the truth.    My question and in fact the entire point of this thread is an exploration into the levers of wear which happens no matter how well we maintain our powertrains.    Some of these levers we exert a good deal of influence over which can and do result is lower wear, longer powertrain life. Some others we are sort of stuck with.    An engine is typically done when the ring to bore seal no longer is able to do the job effectively. Normally the first thing to go in a engine otherwise well maintained and adult driven is this seal.    Looking into the means, methods, products and attitudes that influence the rate of wear seems a worthwhile inquiry to me.     

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...