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Chevy Silverado and GMC Sierra Transmission Problems

503 messages,  Last post on Nov 10, 2009 at 5:28 PM

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What is this discussion about? Chevrolet Silverado 1500, Chevrolet Silverado 2500, Chevrolet Silverado 3500, GMC Sierra 1500, GMC Sierra 2500, GMC Sierra 3500, Transmission, Truck

#167 of 503 More Problems 93 5.7/4l60 not shifting by fgr8frk Oct 14, 2007 (12:01 pm)
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 Replies to this message: bamagal1 (Nov 06, 2007 11:24 am)
#168 of 503 Transmission Oil Change Question by maxwell10 Oct 14, 2007 (4:28 pm)
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? Replies to this message: 1offroader (Oct 14, 2007 6:27 pm) maxwell10 (Oct 20, 2007 5:42 pm) 1offroader (Oct 20, 2007 7:06 pm)
#169 of 503 Re: Transmission Oil Change Question [maxwell10] by 1offroader Oct 14, 2007 (6:27 pm)
Replying to: maxwell10 (Oct 14, 2007 4:28 pm) 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 ). 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.   1offroader Replies to this message: maxwell10 (Oct 20, 2007 5:42 pm) 1offroader (Oct 20, 2007 7:06 pm)
#170 of 503 Re: Transmission Oil Change Question [1offroader] by maxwell10 Oct 20, 2007 (5:42 pm)
Replying to: 1offroader (Oct 14, 2007 6:27 pm) 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? Replies to this message: 1offroader (Oct 20, 2007 7:06 pm)
#171 of 503 Re: Transmission Oil Change Question [maxwell10] by 1offroader Oct 20, 2007 (7:06 pm)
Replying to: maxwell10 (Oct 20, 2007 5:42 pm) 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.   1offroader
#172 of 503 1998 chevrolet z71 speed sensor by zavier13 Nov 03, 2007 (1:50 pm)
does anyone know where the speed sensor is located on the transmission of a 1998 chevrolet silverado z71?
#173 of 503 Re: More Problems 93 5.7/4l60 not shifting [fgr8frk] by bamagal1 Nov 06, 2007 (11:24 am)
Replying to: fgr8frk (Oct 14, 2007 12:01 pm) 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.
#174 of 503 Allison 5 speed - slack on takeoff by citizen48 Nov 09, 2007 (5:33 am)
2001 GMC Sierra CC 8.1L 5 speed Allison 2 WD 62,000 mi -   Experiencing slack on takeoff -   Transmission?   U joints?   Any ideas?   Any help appreciated!   John
#175 of 503 Do I have an Allison? by lillies Nov 12, 2007 (9:54 am)
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? Replies to this message: citizen48 (Nov 12, 2007 4:01 pm)
#176 of 503 Re: Do I have an Allison? [lillies] by citizen48 Nov 12, 2007 (4:01 pm)
Replying to: lillies (Nov 12, 2007 9:54 am) 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 option...run it 95mph and if your only running about 2600rpm on the tach...it's an Allison...LOL   Hope this helps!

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