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Chevy Silverado and GMC Sierra Transmission Problems



  • my 2000 old style chevy pickup will shift out of OD on a slight hill then not shift back into OD. When this happens it will shift hard or jerk from 1-2-3.

    What I did was add a qt. of Lucus transmission oil to help clean sticky valves. it did help, but it still does it every couple of months.

    Just stop turn it off let it sit awhile and works ok.
    ????????????? who knows.
  • tansmission keeps popping out of gear as soon as it is shifted into gear shift light starts blinking and thats all it will do. Dealer spent 17 hrs labor and still couldn't diagnosis problem replaced tcm and shift solenoid. I have also had to replace neutral saftey switch twice truck has only 60,000 miles on it I would appericiate any feed back or similar problems solved.
  • jimm58jimm58 Posts: 1
    My 1997 C1500 trans has been slipping a bit for quite a while. I am trying to determine if it needs the VCM jumper kit to resolve the 4L60e slip problem. My VCM service number is 16229684, the service number of the fixed VCM is supposedly 16244210. Does this mean that I need to install the jumper kit (part # 12167310)? My transmission is exhibiting the symptoms of the TSB (00-07-30-026) that fixed the bad ground problem. Thanks, Jim
  • I have the 2007 1500 6.0 vortex max.
    bought the truck july 5th was great for 3 or 4 weeks then
    it started bucking or jerking going up grade, sometime at a stop light it would feel like someone hit me from the rear.
    dealer says they can't find anything wrong.
    also mpg dropped from 20 mpg to 16 mpg.
    did your drop before your fix? and did your warrenty cover the fix?
  • Dude,
    thats the same truck i got.
    What kind of problems were
    you having.
    Mine does the jecking thing
    going uphill and feels like someone hit
    me at lights
  • Yes,
    i bought my truck 4 door 1500 vortex max on july 5th
    notice the leak a week later and they also said it
    was the front trans pump seal from a nick on the torque converter shaft. do you have any other trouble with your truck jerking or bucking going up hill?
  • GM did replace the tranny of my VORTEC MAX at 7,000 miles, mine never jerked it just felt like it went into a "freewheel mode". the tranny temp went way up.
  • mdsxs4mdsxs4 Posts: 9
    It is actually a 2006 1/2. It is the old body style 2007. The first time the transmission lost all but 1st and reverse. the second time the transmission would shift so hard that the rear end would bang. I was afraid that it would ruin the rear end. When the dealer took it apart they said that it was full of metal shavings. I drive the truck for work on the highway a average of 50,000 to 60,000 miles a year but they are all highway miles and I don't pull a trailer.
  • All you folks with these 2007 1500 tranny problems..tell me a liitle more about what you have. Are they 4x4's, what size motors, what kind of driving are you doing, what were the remedies, did you follow break in procedures correctly? The reason I ask is I just purchased a 2007 with the new body style, it has the 5.3, LT2 package, 4x2, HD towing. I have only owned mine for 2 days now but I must say..I LOVE MY NEW TRUCK!!! To me this new Chevy is the best thing since sliced bread. The ride is far better than ANY truck I drove to include all manufacturers except Nissan. The interior in the LT2 with Leather is far nicer to anyone else and the 5.3 has plenty of power and better fuel economy than the smaller 4.8. So please tell me a little more about your rigs and how you drive em and the reasons for the failures. Thanks
  • My truck is the new body 07. 6.0 vortec max 1500 (HD tranny tow package) (4x4 not Z71, just 4x4) A/T tranny, 20" factory street wheels, LTZ 4door, w/all the bells. The tranny always had a slight fluid pump type noise(only slight) and started screwing up and went out over a weekend. It seemed to free wheel and the tranny temp was much higher than normal. Dealer said to went to pieces when they opened it. they thought something must have got left out in assy. The new one seems fine and no more fluid whine noise. 14,000 miles now and all is well.
  • Thanks for the info BD. I'm still in the break in process and fully intend to do the recommendations. Day 3 now and still no problems for me.

    Thanks again.
  • Found the problem.
    A guy told me to check the brake light switch and make sure it was adjusted correctly, and it wasn't.
    Everytime it hit a bump the pedal would bounce slightly and the switch was cancelling overdrive.
  • Fixed one problem, now have a bigger one.

    Truck has 190,000 miles.
    It does not shift out of 1st unless you run it up alittle and let off the throttle and then I think it shifts straight to 3rd, not sure though, it feels like it is in between(doesn't feel like 2nd), and still pulls good. It does feel like it is shifting to overdrive at about 35-40 but not locking up. Rpm's seem to high for 3rd gear though.
    Reverse works and it pulls fine. Will not shift manually, and if you put shifter in 2nd it disengages like you put it in neutral.
    I changed fluid and filter, and 2 shift solenoids(1-2 & 2-3) first, still the same.
    Changed pressure silenoid and it did make it(when it does shift)shift harder.
    It has not set any trouble codes.
    Anything would be helpful, Thanks
  • Had the transmission oil changed in my 2000 oldstyle Chevy 3/4 ton at 60K. Do not know if Chevy dealer changed filter and oil or back flushed system.

    Question: Is it better to drain oil and change filter or have transmission back flushed?
  • Backflushing removes all of the old fluid. Just draining does not get rid of the several quarts that are inside the torque converter. But backflushing can be a lot more $, esp. at the dealer. I drain ATF about every 30K miles and don't worry about backflushing, or second draining, because the ATF is always pretty fresh. But, if it's been awhile, you can drain it, refill, then drive around for a week or so and drain it again. That will get rid of about 80% of the old fluid (along with a lot of the new fluid from the first draining :cry: ). It's cheaper than a backflush and you can do it yourself.

    An analogy is the radiator coolant - drain, fill with water, drive around, and drain again and refill w/new coolant. This gets out all the coolant that is sitting in the engine block that doesn't come out when you just drain the radiator.

  • Thanks for the reply,

    sounds like draining is right for me, my 4l80e transmission has a drain plug.

    What about changing filter,

    I had transmission oil changed at GM dealership (60K). Nothing was said about a backflush so I am sure I got a oil/filter change.

    Truck now has (77K)

    Do you change filter and oil every 30K?
  • I've done trans filter changes before but I notice that most trans "filters" aren't really filters at all, they're just coarse screens, almost like window screen size mesh. Take a look at it, if there's no junk on it leave it alone and save your $. Those kind of filters are just there to catch big chunks, not really fine particles. I can't personally say about yours, haven't seen it.

    I have a 99 Trooper, it has a GM trans in it, you can't even get inside to change a filter (if it even has one), I just drain the ATF and refill. No trans probs at 70K.

  • does anyone know where the speed sensor is located on the transmission of a 1998 chevrolet silverado z71?
  • Recent professional rebuilt my automatic Turbo 400 tranny in my 1985 C30 1 ton Dually Crewcab pickup that has a 454 ci engine. Problem occurs between 55-65 mph after driving long distance on freeway for aproximately 1-2 hours. Tranny acts like it goes into neutral (similiar to pushing a clutch in on a manual transmission). Tranny re-engages once the vehicle slows down under 55 with foot off gas pedal or if you floor the gas pedal. Above 65 mph and below 55 the tranny stays in gear and shifts properly. It down shifts properly to pass cars or to climb a hill. The professional has went through the tranny twice, had new torque converter rebuilt, states everything looks good and is not sure what is causing the problem. Need expert help on this strange tranny problem. Does anyone have a solution?
  • I have an 05 4x4 1500 sierra (automatic) with 38k miles. I always thought it shifted funny but last week it became extremely sluggish shifting. By that evening - to get it to shift from 2nd to 3rd, I had to rev it up 2 or 3 times & let off before it would shift. The next morning, it would shift from 1st to second then to neutral, and would not come out of neutral without coming to a complete stop. My reverse and 1st & 2nd worked fine. No service engine or service anything light came on. Had to drive it to dealership in "2". I took it in (luckily I had an extended warranty) and the dealer installed a new transmission.
  • Sometimes when a trans is re-installed the shift linkage needs to be re-adjusted.

    Check to make sure that the shift linkage is adjusted correctly. There are detents in the column shifter for each gear, and there are definite "notches" on the shifter arm on the trans for Park, Reverse, Neutral, Drive, 2, and 1. If your column shifter says you are in Drive, but the trans shift arm is not all the way in Drive, you can have weird problems.

    Disconnect the linkage at the trans. Move the trans shift arm into Drive - it will click firmly into place. Move the column shifter into drive, if necessary have someone hold it exactly in place. If necessary, adjust the linkage such that Drive on the column and Drive on the trans shift arm are aligned. Don't align Park with Park, because when you shift the trans into Drive it may be slightly misaligned causing strange shifting behavior.

    Also, the shift linkage may be sloppy from age on a 1985. I'm not sure, but there may be some shift linkage bushings & etc. that can be replaced to tighten everything up and make aligning the column shifter and trans shift arm more precise.

    Is that a clear explanation? The mechanic might have done this but it doesn't hurt to check, it's easy, quick, and free. Good luck.

  • 2001 GMC Sierra CC 8.1L 5 speed Allison 2 WD 62,000 mi -

    Experiencing slack on takeoff -


    U joints?

    Any ideas?

    Any help appreciated!

  • I recently bought a used 2003 Sierra HD Duramax. The salesman said it had an Allison. My neighbour said that Allison should be indicated on the model plate on the side of the truck, but ours simply states "DURAMAX - SIERRA 2500 HD".

    How do I tell if it has the Allison?
  • The only way I know to tell you is if you can look underneath the cab area and you can see a screw on/off small filter (looks just like an oil filter) separately from your oil filter, then it is an Allison.

    One other it 95mph and if your only running about 2600rpm on the's an Allison...LOL

    Hope this helps!
  • HI
  • I just bought a used Silverado, 2WD, 4.3L, W/ a 5-speed. After driving it 150 miles, yesterday a.m. leaving for work, I started it, pushed the clutch pedal to the floor. The fluid level was fine, couldn't get any pedal. I sat stewing for 30 min., and it finally let me shift.The idiot at the car lot said to pump the clutch pedal, then he told me to bleed the slave. Any ideas?
  • I have a 2005 silverado 3500 4wd with the 8.1L. My problem has me stumped. I started the truck early in the day, started to work and the trans light came on. The truck would not shift right. I hooked up the hypertech and got the codes for sensorA, B, C, D, E,. I checked the plugs all was fine. I cleared the codes and the truck shifts fine now. BUT the battery light stays on after the truck is turned off and it drain the battery. I dont know if its grounded out or the ecu is fried........
  • Hi, I'm new to this board, please be gentle. Thanks! I have a new (4890 miles) chevy silverado with the 6.0 litre Vortek Max and auto 4 speed tranny. Everything has been great up until this morning. Drove it to church, got in it ready to come home, and notice there is no indicator marking present to let me know what gear I am in. Waiting to get out of the parking lot, a loud click comes from somewhere in the dash every time I release the brake pedal. Now, I get her out on the road and BAM! She shifts into 1st gear hard enough to throw me back in the seat, same with second. I finally get her home, switch off the engine, and check the tranny fluid. Bright red and right on the mark where she should be, so I get back in it and try it again. This time the indicator light under the gear selections reappear, and I drive her about a mile down the road shifting flawlessly when...BAM! engine service light comes on, clicking back in the dash, and even more harding shifting limping back home. Of course, I will be at the dealership first thing tomorrow morning, but wondering if anyone out there has any ideas or experience with this problem? Thanks in advance!
  • Mine is an 07 new body style. bought it last Dec right after they came out. at 7,000 miles mine didn't make a noise at all it just freewheeled and seemed to be in neut. after i let it cool for 10 min it would go again for about 5 miles. when i got home i put the keys under the mat and left it in the street and called the dealer. when they opened it up they could not find all of the lock rings that should have beenin the tranny.
    they ordered all new stuff. it has 18,000miles and hasent missed a beat. I had a cat back system put on it at 17,000miles so it could expell more exhaust. sounds better seems to run better and i have picked up mpg from 10.6 to 11.5. also at about 17,000miles it has picked up some pep at low speed. good luck.
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