Stay away from the eight speed unless you like spending time at the dealer and driving a loaner. Horrible transmission that is nothing but a headache, and this is coming from the transmission guy at a GMC Buick dealership.Do as you wish, just trying to help.
mjm-1957 replied to SouthpawHD's topic in 2014-2018 Silverado & Sierra 1500That transmission has been a problem since it was released in 2014. The first ones were built with too much clearance between the steel clutch plates and the case. The clunking and noises they made were unbelievable. Unfixable also, we were checking the build dates and the Julian dates on the trans themselves and relaying that off to GM and they would then send a complete replacement.Then the shifting problems started,delayed engagement into reverse after sitting overnight, delayed engagement into drive anytime, harsh 3-2 or 2-1 downshift that felt like you got rearended.We were updating the updates, performing fast learn adapts etc etc etc.Then the TCC shudder started showing up,are you kidding me? First we were told to drop the pan ,replace the filter and blow out the cooler lines and run it for ten minutes on the lift, drop the pan again, drive it on the lift for another ten minutes and another drop of the pan and maybe it will get better after it is driven 200 miles.All of this is done while burning your arm on the cat because they couldn't even put a ****ing dipstick on that piece of shit.I almost forgot the countless valve body replacements to try and correct some shift quality concerns. The six speeds have been virtually trouble free compared to the eight speeds.
mjm-1957 replied to SouthpawHD's topic in 2014-2018 Silverado & Sierra 1500Your much better off without the 8 speed, nothing but a headache.I am the transmission guy at a GMC Buick dealer and the M5U leaves alot to be desired.....
That valve is there to provide back pressure when in 4 cylinder mode. The valve is normally closed by spring pressure. Doubt highly if it would cause a nostart.The o2 sensors require some exhaust stream back pressure to accurately monitor the fuel trims. Thats why its there in the first place.
Does it feel like driving over rumble strips? Sounds like the beginning of TCC shudder. Extremely common problem with the 8 speed M5U transmission.Have your dealer check out TSB 16-NA-175 and they will probably replace the filter and change the fluid, update the calibration for the trans and do a fast adapt relearn.Good luck.
Have them check the connector by the front left corner of the oil pan by the vacuum pump. The terminals may have backed out or it may not be seated all the way. That is a cam position code, have also seen that connector turn green from corrosion.Sorry to hear about all your problems.What was the oil leak?
mjm-1957 replied to Pacfanweb's topic in 1973-1987 Chevrolet & GMC Square Body / Rounded Line PickupsSorry to hear that about your dog. Had to put my German Shepard down from liver cancer and it wasn't easy. Felt like losing a member of the family.
mjm-1957 replied to starman8tdc's topic in 2000-2014 Silverado & Sierra HDTell your buddy to look again, thats how you get the converter bolts.There is no starter hole, get the starter out of the way and get a swivel 15 with an air ratchet and you can get to them.
mjm-1957 replied to starman8tdc's topic in 2000-2014 Silverado & Sierra HDPull the intake for access to the bell housing bolts and get the starter out of the way for the converter bolts.
Could have been a total write off such as a flood car, very common up here in the north east. Once the insurance company pays off the title is listed as salvage and the block is applied. Could also have been something to do with fraud and they got caught. Shouldn't matter that the truck is not in the same area it was sold in as far as the warranty coverage applies. If you bought it from a GM dealer it should not have been delivered with open campaigns.
That is the engine it was built with. GM has a warranty block on that VIN number. Fully voided.Something must have happened to make them do that. We don't see many blocked warranties and we run 45-55 cars a day threw the shop. Was delivered in the middle east 4/21/16. Also has 2 open campaigns on it 28770 and 16007. First one is a transfer case control module software up date and the second one is an air bag module software update.
No one can fix it because it is a pisspoor design that should never have been released to the public in the condition it was. Rushed out to keep up with other 8 speeds out there already. I am the guy who gets to try and fix the unfixable. I am the transmission guy at a GMC Buick dealer and I can tell you from experience in dealing with this piece of shit since 2014- cut your losses and get rid of it now.You will never be happy with it. Fast adapts, calibration update after update, valve body replacements and the triple flush on Canyon and Colorado and the one time flush on everything else.Band aid at best.Hopefully the ten speeds will be better. Haven't had one complaint yet and they have been out for a while now and the eight speeds were bad from day one.
Hood stays on, just propped straight up after removing the two bolts holding the springs to the hinge.Trans stays in, pretty straight forward job,cooling fans removed, cooling system drained and hoses disconnected, wiring harnesses are moved aside,exhaust disconnected but engine pipe stays in the truck.Intake manifold comes off before the engine is pulled so you can access upper trans bellhousing bolts and fuel pipes,evap pipes etc. AC evacuated and lines removed from compressor , starter ,torque converter bolts and motor mount bolts and thats pretty much it.I pull the right side exhaust manifold while in the truck to allow the engine to turn side ways to get it out past the radiator support and the firewall, tight squeeze but it goes in and out without damage.
Was the pushrod bent or actually broken? We have seen many with bent pushrods or broken valve springs, but never with an actual broken pushrod. For it to be broken , the valve must have kissed a piston and physically damaged the piston and block. They don't let us put in an engine unless it can't be repaired.They are getting tighter and tighter with replacements. They are having us check the calibration history and to make sure it's the factory calibration and not tuned also.
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