To clarify, the TV cable on the TurboHydromatic 350 is only for kickdown, not shift points. The vacuum modulator controlled that.

Back in the late 80's, a guy in our city that had retired from the GM plant in town and started a used car lot. Being a GM retiree, he wanted to concentrate on GM cars, but everything he was buying was giving him transmission problems, so he started buying more of the Taurus and Sables, and was not having those problems with them, so he started to concentrate on those. He said he had to keep a couple of GM's on the lot, because it was a GM town, but began to favor the Ford front wheel drive cars. I bought an 89 Mercury Sable off of him, and was the first front wheel drive car I had ever owned, and really liked it. That thing would drag itself through snow so deep, it would drag the whole bottom on it, and keep going.

GM is famous for letting the customer sort their problems out for them, Then they perfect it and the next year they kill it. Same can be said for their Engines!

Disable the lock up is smart.

I helped my dad rebuild the Roto-Hydramatic in my grandmothers 62 Olds around 1968 or so. Man that thing had a lot of parts! But when we put it back together it seem to be fine for the 6 or 7 years she continued to drive it. They did have a very odd method of operation though. I will confess to having a real soft spot for the post 1956 Buick Dynaflows which I thought were great transmissions after they started using the dual stators with the switch pitch.

The lockup transmissions were not unreliable, only the lockup solenoid that would stick & fail to release. The cure was free & easy. Unplug the solenoid. Now you're left with a rather normal transmission. I did it a lot. Cost about 1 mpg.

If it ain't broke don't fix it, HELLO ALL U ENGINEERS OUT THERE THAT REINVENTING THE WHEEL.

I'm surprised the TH180 (or as it was known here in Australia as the Tri-Matic) didn't make the list. Fine behind a four cylinder or weak 6 cyclinder but as soon as it was put behind even a low output v8 it became a Traumatic rather than Trimatic!

4T60E was notorious for destroying the reverse reaction drum or "stove pipe" so much that aftermarket companies were offering hardened versions of it. This really was a big problem when mated to the LQ1 3.4L DOHC engine in the GTP and Lumina possibly due to the high torque the engine could deliver at high RPMs. In fact, I remember reading about the development of the LQ1 saying GM initially intended it to deliver 250 HP or something crazy like that but had to scale it back due to transmission reliability issues.

Pontiac even put that damm ROTO in my GranPrix; the shifter got so hot pulling a boat trailer had to use a glove. Life span ? very short. Now my '62 Bonneville had the latest and greatest 4-S Hydramatic and it moved that big cruizer around with precision.

I remember attending a Chevy/GM event at the Indy 500....all the new cars were on display including engineering cutaways. At the automatic transmission display, I made a comment that my BMW had a GM transmission..if I recall my E46 3 Series Touring used a version of GMs 5L50E..a GM employee at the display said..."well that is one thing we do well."

Fascinating. Keep up the Porch Chats™, Adam, loving this "Best & Worst" series.

Great stuff not a bunch of music or flash just a porch an the day an something to talk about.... simply great stuff 👍👍👍👍

I don't know why I like your videos but you have a real talent with the spoken word. No hype, just communication.

Been a mechanic for 25 years really enjoy your videos great information

I am a service manager for a national used car retailer, and the 14 up 8 spd transmissions are crud. The "Magic Fluid" flush can stave off internal repairs for a time...but the 1-2 upshift and 2-1 downshift clunks come back and destroys internals. Nice vid!

Another very compelling video. Having rebuilt and destroyed a number of GM4L70E transmissions and spent way too much time in the Transtar and Sonnax catalogs, it's a topic near and dear to my heart.

“…you enjoy forms of torture!” 😂 YES, I have rebuilt ONE of those roto-messes and NEVER AGAIN! Very torturous indeed! Took me awhile but I’m finally getting around to watching/listening to this & “best transmissions” porch chat vid’s. So glad you mentioned that incredibly well engineered 425 setup. Was a very interesting combination of tech; I own two 1955 Buick Super Riviera’s, both w/“Switch Pitch” or, as was newly called then, “Variable Pitch” Dynaflow! Also had inherited my grandfather’s 1975 GMC Palm Beach Motorhome with 455 Olds front wheel drive trans setup.. loved that motorhome

Hello Adam, thanks for sharing another porch chat, I'm really enjoying them & learning a lot of interesting facts!! 👍👍

Adam, you did my old heart good by giving the Slim Jim "worst of all time" honors! I learned to drive on our 1963 Olds Super 88, and all these years later, I can still feel dying fall of the shift from first to second. But it never left me stranded. That Olds was traded on a new 1972 Pontiac Catalina. Two weeks after we got it, the transmission literally fell out of the car at 35 mph.