GMC Safari Trans Grinding: Signs of Transfer Case Failure

Had a similar issue with my 1999 GMC Savana. I have some experience with transfer case problems and can share what happened with mine. The symptoms started exactly like yours, gear grinding and rough shifting. Initially thought it was just low transfer case oil, but the mechanic found worn gears in the transfer case causing metal particles to contaminate the oil. The repair involved: Complete transfer case disassembly, Replacement of defective gears showing mechanical wear, New seals and gaskets, Fresh gear oil Total cost came to 330 Euro for parts and labor. The repair solved all shifting issues and prevented potential transmission damage. Before suggesting specific solutions, could you share: Current mileage, When you last changed the transfer case oil, Any unusual sounds during acceleration, Whether the issue occurs more when cold or warm This information would help determine if your issue matches what I experienced with my Savana or if its something else entirely.

Thanks for the helpful information. My current mileage is 66041 KM and last service was completed 6 months ago. The issue definitely gets worse when the engine is cold, especially in the mornings. During acceleration, there is a noticeable whining sound coming from the transmission area. The transfer fluid has not been changed since I got the vehicle, so that could be contributing to the gear wear issues. Based on your experience, it sounds like I should get the transfer case oil checked first before more serious problems develop.

Based on those symptoms, especially the cold-start issues and whining noise, it sounds nearly identical to what I experienced with my Savana. The gear wear became more apparent after I ignored the initial signs. The transfer case oil is the first thing to check. Going so long without a fluid change likely accelerated the gear wear in your transfer case, just like it did in mine. That whining sound during acceleration is a clear warning sign, it is typically caused by metal particles from worn gears contaminating the gear oil. Quick tip from my repair experience: Request that the mechanic checks the transfer case oil condition using a magnetic probe. In my case, this revealed metal shavings that confirmed internal gear wear before we did the full teardown. Even if you need the same repairs I had done (new gears, seals, etc.), catching it now while the grinding is still intermittent will likely prevent the 800 Euro+ repair bill I would have faced if the transfer case had failed completely. The cold weather performance issues suggest the transfer case oil has degraded significantly. When the oil is worn out, it thickens more in cold temperatures, making the gear grinding and shifting problems more noticeable until things warm up.

Really appreciating all the detailed information and tips, especially about the magnetic probe test. The similarities between our cases are striking, particularly regarding the cold weather symptoms and gear wear indicators you mentioned. Given how my transfer case oil has never been changed and the obvious oil leakage I found, I will get it checked right away rather than risk more extensive damage. The 330 Euro repair cost you mentioned is much more manageable than dealing with a complete failure. I will schedule an appointment to have them inspect the transfer case and check for mechanical wear using that magnetic probe method you suggested. The whining noise during acceleration definitely has me concerned about metal particles in the gear oil, just like your situation. If they find similar issues, at least I know what to expect in terms of the repair process, transfer case disassembly, replacing worn gears, new seals, and fresh fluid. Better to address it now while the grinding is still intermittent rather than wait for catastrophic failure. Thanks again for sharing your experience.