What is considered high mileage on used Hybrid GMC Yukon? I am considering the purchase of a used Hybrid GMC Yukon or Chevrolet Tahoe. Is 125,000 high mileage for a Hybrid, like a standard gasoline V8 engine in these suvs?
Welcome to Motor Vehicle Maintenance & Repair! The thing about the GM truck hybrid is, all of the hybrid action is done through the transmission. The engine is the same as what comes in the regular Yukons (most likely the E85 capable 5.3l V8). The engine will last just as long (or as short as) any other regular 5.3l LS based V8 (dependent upon maintenance/upkeep). The hybrid function is more of a helper rather than a true hybrid, but will still get you better gas mileage. I have no data on the longevity of the batteries associated with these vehicles, though.– Pᴀᴜʟsᴛᴇʀ2 ♦Feb 12, 2019 at 15:19
2I think this is a matter of opinion and impossible to answer in a binary fashion: a) one person's "high mileage" is another person's "just getting broken in," and b) the individual vehicle's condition — how it was treated and maintained — is significantly important to its future prospects and how they fit with your plans. Your best bet would be to have it looked at by a mechanic you trust.– DavidRecallsMonicaFeb 12, 2019 at 15:22
1Not only a mechanic you trust, but one which knows GM hybrids.– Pᴀᴜʟsᴛᴇʀ2 ♦Feb 12, 2019 at 15:36
the mileage isn't a real issue for a hybrid system. It's the age of the battery.– John LordFeb 12, 2019 at 19:30
I don't have specific experience with GMC Yukon or Chevrolet Tahoe hybrids, but I do know quite a bit about Toyota hybrids.
Basically, the transmission is nearly indestructible, being based on an electric CVT approach. If you ever manage to destroy it, replacement of the transmission with its two integrated electric motors costs less than replacement of a conventional automatic (or manual) transmission. If a single electric motor fails, you don't replace it, you replace the entire cheap transmission!
However, the transmission in GMC Yukon hybrids seems different, being partially based on automatic transmission technology and not just planetary electric CVT technology. So, the risks in purchasing GMC Yukon hybrid are larger than the risks of purchasing a Toyota hybrid, being probably similar to the risks of purchasing a used automatic transmission vehicle.
The inverter can in theory fail, containing lots of power electronics. However, inverters are used in many other environments like locomotives, elevators, etc. and typically they are expected to have quite long service lifes, so I don't believe inverter failure is the largest thing to worry about. If there ever has been a cooling circuit leak (inverters are water-cooled, or more accurately coolant-cooled), I would worry about inverter failure.
That leaves the battery. Toyota hybrids have extremely low battery failure rate, and Consumer Reports has tested the mileage of 200 000 mile driven Prius (spoiler: the mileage was just fine). But, Honda hybrids have had higher rates of battery failure due to imperfect charging algorithms when subjected to certain driving patterns. Basically, the chances of NiMH battery lasting for the expected service life depend on the charging algorithm.
Where I live, Toyota offers 350 000 kilometer warranty for the hybrid battery. They wouldn't offer this warranty if they didn't trust in the technology.
I would therefore treat purchase of a high-mileage used hybrid like the purchase of any high-mileage used car. I don't see how the hybrid technology would make it more risky. In my opinion, the long-term durability of these components should make the purchase less risky.
For any used car purchase, you should know what the weaknesses of the particular model you're planning to purchase are. This applies to hybrids, but hybrids have far less transmission related weaknesses.
1The link to wiki you provide states: "...the electric motors allow it to function as a continuously variable transmission. This variable ratio functions in addition to the torque multiplication of the planetary gears." ... looks like it does perform as a CVT (to some extent).– Pᴀᴜʟsᴛᴇʀ2 ♦Feb 12, 2019 at 19:28
@Pᴀᴜʟsᴛᴇʀ2 it seems to be a combination of electric CVT and automatic transmission. But I'll edit.– juhistFeb 12, 2019 at 20:26