I made this page to vent my anger at Drive Train Specialists (or Drive Train Screwups or just plain old DTS), located in Livonia Michigan.  The following provides a chronological explanation of what happened.  It should be noted that my car was original, perfect running condition before they (DTS) worked on it.  Everything was in good working order, there were no leaks and no noises.  They only thing I wanted them to do was change the gear ratio, replace any worn bearings / seals and add an Eaton posi unit (to replace the stock Auburn unit).

1)                  I had DTS rebuild the differential and change the gear ratio in my 1995 Caprice, on 2/24/00 @ 98700 miles.

2)                  Approximately 4 months later and more importantly with only 653 additional miles on it, I drove the car across the country to California.  It should be noted that when I reached California the car only had 3653 additional miles on it and almost 3000 of that 3653 miles was the cross-country trip itself.  This is still WELL within DTS's so called "warranty" period.

3)                  A little more than ¾ of the way across the country, the differential started making a whining noise and started to produce a slight vibration.

4)                  I stopped on the side of the road in Utah, because the noise and vibration was getting worse.  I noticed I was able to move the pinion vertically up and down in the housing approximately 1/8 of an inch (I was physically able to move the yoke on the rear of the drive shaft up and down and it was NOT the universal joint).  Being out in the middle of nowhere (literally) and almost to California, I saw no plausible alternative but to continue driving.

5)                  Immediately upon my arrival to California, in fact the next day, I took the car in to a Chevrolet dealer to get the noise and vibration evaluated.  By this time the differential was quite noisy.

6)                  The Chevrolet dealer initially advised me that the differential was probably in need of a complete overhaul including the ring and pinion due to the amount of miles on the car.  I informed the dealer that I had just replaced the entire ring and pinion including all the bearings and seals a few months earlier.  The dealer suspected a faulty part or a defective install job of the components I had just replaced.

7)                  The dealer recommended that I not drive the vehicle for safety reasons and recommended they disassemble and inspect the differential assembly to more accurately determine the cause of the noise / vibration.  Additionally, in a speculative conversation with the actual mechanic before the differential was further inspected, I discovered that we both suspected a bearing had failed or a another part was defective and the resulting debris (metal particles) further damaged the ring & pinion and possibly the rest of the bearings in the differential.  I gave my consent to the dealership to determine the cause of the problem.

8)                  Upon disassembly of the differential, it was found that the inner pinion-bearing race was not seated correctly into the differential housing.  The mechanic stated “...there was a small “nick” present in the race seat [mating surface to the race that mounts in the differential housing]…”  He further stated “…the nick was apparently caused by a punch [a tool used to remove the part] trying to knock [remove] out the original race from the housing…”  The nick prevented the newly inserted race from seating properly in the differential housing (see pictures #’d 6 or 7).  The mechanic determined that the differential failed because the improperly seated race caused the pinion to become loose in the housing (the pinion was able to move both vertically and horizontally in the vehicle).  I authorized the dealer to repair my vehicle.

9)                  After I authorized the repairs I immediately called DTS to get their warranty department involved (at the time of the failure the work DTS performed was under “warranty” in both miles and time from date completed).  I was informed that the only way I could obtain warranty service was to bring the vehicle back to DTS (at my expense) and that they would only be liable for the parts replaced (not the labor).  This is a ludicrous suggestion because in order to transport my car from California to Michigan, it would have cost me more than the repairs cost at the dealership.

10)              I flew out to Michigan, visited DTS on 8/11/00 and showed them the parts.  I spoke to a sales associate named “Salseman #1”.  He had a DTS mechanic look at the suspect parts and then he informed me that he would contact the appropriate people of my situation.  I was told there was no need to leave the suspect parts with them; therefore I brought the suspect parts with me back to California.

11)              Two weeks passed, I heard nothing.  I called them on 8/21/00 and talked to “Salseman #1”.  I was told the owner would be out for the rest of the week and to try back after he returned.

12)              I again waited two more weeks and called back on 9/4/00. I talked to a salesperson named “Salseman #2” who said, “You would be lucky to get reimbursed for any of the work you had done because the dealership sold you a bunch of parts that you did not need at a great expense”.  I was very displeased with his opinion. (I have extensive GM dealer training as a mechanic, in addition I am a practicing Mechanical engineer and hold a degree of Masters of Engineering from MSU and University of Michigan) and told him that I watched the mechanic disassemble the differential and I saw the misassembled parts first handedly. The removed parts were not re-useable.  (See pictures #’d 1 - 7).

13)              Finally, on 9/11/00 “Salseman #2” called and left a message for me to call him at DTS.  When I contacted him, he told me that the only thing they were liable for was the ring and pinion, nothing else.  He said he was going to forward my case onto their “warranty” department for follow up.  I have heard nothing since this date.

PHOTO EXPLANATION  

    a) The amount of debris that was present in the differential oil due to the bearing failures.

    b) The amount of wear is excessive 3653 miles after DTS did their work (carrier side bearing preload was set up too tight)

#2 Illustrates the “tilted” pattern as a result of being “cocked” in the rear end housing.  The small nick (see pictures 6 and 7) in the housing caused the lower pinion race to run at a slight angle to the bearing, thus creating this funny, irregular pattern on the race.