Are we talking current units, or historical?
Current units that I see very few issues with:
ZF 8HP (and it's built under license Chrysler equivalent)
Ford 6R series, which is based on the ZF 6HP. Fun fact: you can use a Ford 6R pan and filter on a 6HP transmission in other applications. The only reason I know this is due to having to do a trans service on a Range Rover and discovering that the OE 6HP trans pan has the filter integrated into it. Great idea, but it doesn't allow the pan to clear a welded chassis cross member during removal. The options are: unbolt motor and trans mounts, jack the powertrain up, and hope you get clearance or break the neck of the original filter and replace it with a Ford filter, pan, and gasket. The added benefit of such a conversion is getting a steel pan vs. composite, and a drain plug.
Pretty much any Toyota transmission, FWD or RWD. As others have mentioned.
Basically any Aisin transmission ever made. Used in everything from Volvo's to GM's to Jeep's. Those things just don't give up.
I don't think they're used any more, but honorable mention goes to the Ford 4R70W, the 4R100 (E4OD), and several others that escape memory at the moment. OH! I'll get flack for this, but the Chrysler "Ultradrive" 41TE and it's many variants. The early ones? Pure junk. However, Chrysler stuck by the design and by the mid to late 90's it was a very solid transmission. It also spawned the 62TE six speed unit. Compared to the GM/Ford co-designed 6-speed auto that was released around the same time, it was a staple of reliability. Especially when compared directly to the GM version of said trans, which has a history of issues.
The baddies:
GM 6Lxx (insert torque rating for XX). I've seen far too many fail at sub-100, regardless of engine or vehicle.
GM 6Txx. As mentioned above, this trans was co-developed with Ford. Great idea, until GM originally used a non heat-treated wave spring in the 3-5-R clutch assembly. Needless to say, it almost always breaks, causing major internal damage. The failure rate was so high, they eventually extended the warranty on many applications to 10/120.
Subaru CVT's, from their release. I'm not sure how you under-design a transmission that only has to handle a feeble amount of power from a boxer-4, but they managed. From jerky operation, to TCC lockup issues, to full on failure. 100% avoid in my opinion.
That's really about it for (mostly) current transmissions, at least the ones I see at my shop. There was a slight issue in the late 00's with Mazda 5-speed auto's munching TCM's but that was due to an external, case mounted TCM that had poor potting on the PCB and would let water in. It rarely hurt the transmission itself, but it is about a $1,200 fix.
Current units that I see very few issues with:
ZF 8HP (and it's built under license Chrysler equivalent)
Ford 6R series, which is based on the ZF 6HP. Fun fact: you can use a Ford 6R pan and filter on a 6HP transmission in other applications. The only reason I know this is due to having to do a trans service on a Range Rover and discovering that the OE 6HP trans pan has the filter integrated into it. Great idea, but it doesn't allow the pan to clear a welded chassis cross member during removal. The options are: unbolt motor and trans mounts, jack the powertrain up, and hope you get clearance or break the neck of the original filter and replace it with a Ford filter, pan, and gasket. The added benefit of such a conversion is getting a steel pan vs. composite, and a drain plug.
Pretty much any Toyota transmission, FWD or RWD. As others have mentioned.
Basically any Aisin transmission ever made. Used in everything from Volvo's to GM's to Jeep's. Those things just don't give up.
I don't think they're used any more, but honorable mention goes to the Ford 4R70W, the 4R100 (E4OD), and several others that escape memory at the moment. OH! I'll get flack for this, but the Chrysler "Ultradrive" 41TE and it's many variants. The early ones? Pure junk. However, Chrysler stuck by the design and by the mid to late 90's it was a very solid transmission. It also spawned the 62TE six speed unit. Compared to the GM/Ford co-designed 6-speed auto that was released around the same time, it was a staple of reliability. Especially when compared directly to the GM version of said trans, which has a history of issues.
The baddies:
GM 6Lxx (insert torque rating for XX). I've seen far too many fail at sub-100, regardless of engine or vehicle.
GM 6Txx. As mentioned above, this trans was co-developed with Ford. Great idea, until GM originally used a non heat-treated wave spring in the 3-5-R clutch assembly. Needless to say, it almost always breaks, causing major internal damage. The failure rate was so high, they eventually extended the warranty on many applications to 10/120.
Subaru CVT's, from their release. I'm not sure how you under-design a transmission that only has to handle a feeble amount of power from a boxer-4, but they managed. From jerky operation, to TCC lockup issues, to full on failure. 100% avoid in my opinion.
That's really about it for (mostly) current transmissions, at least the ones I see at my shop. There was a slight issue in the late 00's with Mazda 5-speed auto's munching TCM's but that was due to an external, case mounted TCM that had poor potting on the PCB and would let water in. It rarely hurt the transmission itself, but it is about a $1,200 fix.
