Remanufactured GMC Sierra 1500 Transmissions
- Learn about common GMC Sierra 1500 transmission problems
- Everything you need to know when shopping for a GMC Sierra 1500 transmission for sale
- How and when to buy a remanufactured GMC Sierra 1500 transmission
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Remanufactured GMC Sierra 1500 Transmissions
The GMC Sierra 1500 is a very capable pickup truck. However transmission problems with the 4L60 and 6L80 can reduce its capabilities significantly. So let’s find out if installing a remanufactured GMC Sierra 1500 can provide a more permanent solution to your transmission problems.
Common GMC Sierra 1500 4L60 Transmission Problems
One of the most common 4L60E transmission problems is the complete failure to engage reverse. There are many potential sources of this problem, which is ultimately brought on as the miles increase. The first culprit could be the low reverse clutch pack, where the disks are too worn out to engage reverse gear.
If this is the case, you will likely see metal shavings in the transmission fluid when you remove the transmission pan. Or the problem could be coming from the valve body, which could mean that warping occurred due to excessive heat, or the reverse circuit has failed.
Also, inspect the piston bore for scraping and score marks. This type of wear can lead to future reliability issues. So smooth out the bore with emery cloth, then remove the excess dust/debris with Brake Cleaner.
Harsh or Delayed 1–2 Shift
If your 4L60E transmission is pausing between first and second gear, it could be due to a worn or broken 2–4 transmission band. The steel 4L60E 2-4 transmission band is lined with a friction material that helps it to engage the clutch drum and execute the gear change.
As that material wears away, the band will slip on the drum and delay the shift, or cause it to slip between the two gears. This is a common problem on higher mileage vehicles.
This issue can also be caused by a faulty Throttle Position Sensor/TPS. With the ignition in the ‘On’ position, you can test the 4L60E TPS using a voltmeter. If it is working, the voltage should increase/decrease in a smooth, linear line as you move the TPS. To find the correct voltage readings for your vehicle, refer to the shop manual.
Shudder When Shifting From 1st to 2nd
Another common problem is when it either ‘slams’ into second gear, or doesn’t seem to want to shift into second and the engine just revs.
Take a look at the 1-2 accumulator. This little shock absorber-like device lives inside the valve body and dampens the excess fluid pressure that builds after a gear change. If the little plastic piston or the spring inside of it breaks, you’ll feel the fluid pressure buildup as the transmission sort of jerks itself into gear.
If left un-repaired, this problem will eventually cause serious damage to the clutches and clutch drum assembly.
Common GMC Sierra 1500 6L80 Transmission Problems
Flare and/or harsh 2-3 shifts
Problem – Some drivers can experience an unusually harsh 2-3 shift or flare. They may also experience an usual delay when shifting from Park, Drive and/or Reverse. The symptoms are more likely to happen in colder climates, however they can still happen at any temperature.
Solution – These 6L80 transmission problems can be caused by a leaking 1-2-3-4 and 3-5-R clutch seal rings. The clutch packs, discs and drums should also be inspected for signs of damage. Street Smart Transmission remanufactured 6L80 transmissions come already modified to correct the causes of these problems.
Slips in Reverse or Third, Delayed Reverse or Drive Engagement, DTC P0776, P2715, P2723, Harsh 2-3 Shifts
Problem – Vehicles equipped with the 6L80 or 6L90 transmission may slip when Reverse is selected or have no/delayed reverse engagement, harsh shifts from 2-3 / 4-5 or slips while in fifth, and slipping acceleration when passing. Possible DTCs include P0776, P2715 or P2723.
Solution – This transmission problem may be caused by a cracked 1-2-3-4 / 3-5-R clutch housing
How to Solve GMC Sierra 1500 Transmission Problems
Solution A: Buy a Used GMC Sierra 1500 Transmission
Going to the local junkyard and picking up a used GMC Sierra 1500 transmission might seem like the cheapest and fastest option. But you need to consider the fact that you don’t know what the actual shape of the internal components are. It could very well be on the verge of transmission problems of its own, which would leave you in the exact same predicament that you’re in now. And that 30 – 90 day junkyard warranty probably won’t cover labor charges to install the replacement transmission if something goes wrong.
Solution B: Buy a Rebuilt GMC Sierra 1500 Transmission
Getting a rebuilt GMC Sierra 1500 transmission would probably seem like a better idea. However, a lot of mechanics and transmission shops will only rebuild your GMC Sierra 1500 transmission back to its original factory specifications. Which means that all of those factory design flaws are still going to be in–play. And that rebuilt transmission warranty might only be good at certain shops, which could do you no good if you have transmission problems while you’re traveling.
Solution C: Buy a Remanufactured GMC Sierra 1500 Transmission
If you want to get the most service life out of your little luxury SUV as possible, then you really should consider a remanufactured GMC Sierra 1500 transmission from Street Smart Transmission. Each one is completely disassembled and re-remanufactured, so nothing is left to chance. They’re also modified to correct the factory design flaws, which will greatly extend the service life. Plus, you get a 3-Year/Unlimited Mile Nationwide Warranty. This will cover parts and labor charges at any licensed repair shop in the Continental United States, giving you a lot more flexibility and coverage.