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Transmission Problems, Maybe

Discussion in 'GM Powertrain' started by Davidss, Apr 1, 2010.

  1. Davidss

    Davidss New Member

    I have a 99 Silverado new style, 5.3 auto 2wd. I believe it is a 4L60E transmission. The truck has 96K miles. Ive never had a issue with the transmission until recently. The other day it started upshifting harsh like it was in tow mode but wasnt. Maybe even harsher than tow mode. The next day it did fine and shifted normally. Then three days latter when I engaged reverse and backed up it felt like it was shuddering a little but then the upshifts were normal and it only did this one time in reverse. It has worked fine for the last three days. The fluid level is correct and the fluid looks fine and doesnt smell burnt. I have no mil light on either. I thought I would maybe drop the pan and check for debris first or is there something else I can check before this? Has anyone ever heard of any of this happening before?
  2. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Yeah sounds like you need to do a tranny service and soon. At least a filter.. Sounds like its clogged.
  3. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    The first thing to do is check what trouble code is stored in memory. The reason your transmission shifts hard is the PCM goes into failsafe mode which raises the line pressure. The check engine light does not come on when this happens. Clogged filters will not cause a transmission to shift hard.
  4. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Agreed, i miss read. not to mention Jimmie seems to be quite the tranny guru...
  5. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    Thanks for the complement Murdog. I built my first transmission in 1965. It was a 3 speed out of my 55 Chevy. My friend help my build it and when we got through we had several needle bearings left over. I was holding them in my hand and my friend said "what are we going to do with these?" I threw them over my shoulder and we both laughed. We were 16 years old. The transmission worked and I drove it until I blew up the low slider later on. I have since rebuilt hundreds of transmissions. I counted them one year <1982>. I rebuilt 332 that year and in previous years I probably rebuilt more cause they were easier to build back then. No electronics and no overdrive. I'm 60 years old now and I'm still in the transmission industry. :)
  6. Davidss

    Davidss New Member

    There were no codes stored for the transmission. I have also taken two road trips since this glitch and driven around town totaling about 1500 miles since and everything is normal with no recurrence of any problem. So Iam just going to use it until and if something happens. What else can a person do? Maybe flush the unit for grins which would probably cause it to hatch with my luck LOL

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