got me a TCI t350

[Chillin014]

I was given a th350 that was predicted to have messed up the intermediate sprag and the original owner didnt want to mess with it.
Well after a little "research" it turns out that the governor simply ....messed up. what happened was, the little plastic gear on the end flattened and was melted by the output shaft.
This doesnt seem like a common replacement part although I've seen some on ebay. I was gonna call TCI and ask what they recommend but hey..cant hurt to get a 2nd opinion (or 3rd and 4th).

what causes the governor to fail like this? and why is the gear plastic and not metal? The best place to get a replacement?

my biggest question is...why do people continue to use 3 speed transmissions...three gears?!?! why??

 

[Derision]

my biggest question is...why do people continue to use 3 speed transmissions...three gears?!?! why??

I continue to use the TH350 simply because I'm too lazy to actually replace it with another one. I would love to have one of the four-speeds, but... like I said, I'm lazy. I always figured on replacing it with one of them the day it died -- which, by my driving style, people estimated to be a year or less. Alas, the thing has lasted almost seven years now and shows no sign of dying.

That's my reasoning, at least.

 

[Chillin014]

haha thats what I figured....but I got the transmission from a guy who upgraded to a 400 after it died and I just couldnt figure out why anyone would choose to have a 3 speed in the first place. Doesnt that extremely limit your rear end gear ratio options? I am still learning but if I get a lower gear ratio I could possibly limit my top speed to like 100 mph??? thats real lame.

 

[Derision]

haha thats what I figured....but I got the transmission from a guy who upgraded to a 400 after it died and I just couldnt figure out why anyone would choose to have a 3 speed in the first place. Doesnt that extremely limit your rear end gear ratio options? I am still learning but if I get a lower gear ratio I could possibly limit my top speed to like 100 mph??? thats real lame.

Well, I don't think it's limited that much. I have definitely been able to break 100mph without a lot of work (my little 305 mustered 115 on one occasion -- and survived to tell about it!). But that overdrive definitely makes it easier to do, and the engine doesn't have to work quite as hard.

 

[Chillin014]

haha thats what I figured....but I got the transmission from a guy who upgraded to a 400 after it died and I just couldnt figure out why anyone would choose to have a 3 speed in the first place. Doesnt that extremely limit your rear end gear ratio options? I am still learning but if I get a lower gear ratio I could possibly limit my top speed to like 100 mph??? thats real lame.

Well, I don't think it's limited that much. I have definitely been able to break 100mph without a lot of work (my little 305 mustered 115 on one occasion -- and survived to tell about it!). But that overdrive definitely makes it easier to do, and the engine doesn't have to work quite as hard.

i didnt mean it like that. my speedo doesnt go above 80 but I'm confident that I could get over 100. I'm saying if you change your gear ratio in such a way that you have alot faster acceleration your going to top your car out sooner because you simply run out of gear in the transmission, not because the engine cant push it higher.

 

[Derision]

i didnt mean it like that. my speedo doesnt go above 80 but I'm confident that I could get over 100. I'm saying if you change your gear ratio in such a way that you have alot faster acceleration your going to top your car out sooner because you simply run out of gear in the transmission, not because the engine cant push it higher.

Oh. Dur. Can you tell I'm still half asleep?

Yeah, if you're shooting for acceleration, you're going to top out a lot quicker. That's the trade-off, I guess. Acceleration or top speed. But I'd think that would apply (though to a lesser extent) to a four speed, too.

 

[Chillin014]

i didnt mean it like that. my speedo doesnt go above 80 but I'm confident that I could get over 100. I'm saying if you change your gear ratio in such a way that you have alot faster acceleration your going to top your car out sooner because you simply run out of gear in the transmission, not because the engine cant push it higher.

Oh. Dur. Can you tell I'm still half asleep?

Yeah, if you're shooting for acceleration, you're going to top out a lot quicker. That's the trade-off, I guess. Acceleration or top speed. But I'd think that would apply (though to a lesser extent) to a four speed, too.

lol. well...i guess if you have enough power you can get "longer" (?) gears. okay i need to learn about gear ratios i feel like a tard. when my friend was explaining it I wasn't completely grasping it

 

[Derision]

Yeah, if you're shooting for acceleration, you're going to top out a lot quicker. That's the trade-off, I guess. Acceleration or top speed. But I'd think that would apply (though to a lesser extent) to a four speed, too.

lol. well...i guess if you have enough power you can get "longer" (?) gears. okay i need to learn about gear ratios i feel like a tard. when my friend was explaining it I wasn't completely grasping it

Yeah, I'm not really gear-inclined either (Mongo make engine run, Mongo happy). But I would think that the way to do it would be to have the first two gears be geared for quick acceleration and then three to four be "longer" or whatever for a better top speed.

I really have no idea what I'm talking about. Someone else break into this thread and set us straight, please!

 

[Chillin014]

Haha.

The only concept I understood was that depending on the gears your motor/transmission/driveshaft turns once and your wheels turn how many ever times the gears allow.

So if the gears allowed the wheels to turn more for every one rotation of the motor that would be less work for the motor and faster acceleration. If the wheels turned less for every one rotation of the motor...okay yeah I'm confused.
Where the experts at.

 

[85 Cutlass Brougham]

OK, starting with the reason people run 3 speeds: Durability. The TH350 was designed during a time in which GM engines actually made power and they were built stronger than the 4 speeds in stock form. That being said, the 4 speeds can be built just as strong, you just need to change more parts to do so. The 3 speeds have a few weak points like sprag failure in TH400's in drag race situations, mostly during burnouts.

As for gearing, it all depends on what you intend to do. You have to pick gearing that fits the operating speed of the car and the engine. The torque curve must be considered when choosing a gear as an engine with tons of low end torque will not need the extra multiplication off the line that a high RPM horsepower engine will need. In fact, a torquey engine can be slower with too much gear because of excessive wheel torque at launch that will make it impossible to get off the line. I actually prefer the TH200 4R for a street application because it has closer gear spacing than the TH700 R4 and does not have such a drastic drop on the 1-2 shift. It also has a better overdrive by a few points. I run a 3.23 rear gear, but my engine produces an abundance of low end torque and any more would make it undriveable. However, my car is geared towards street driving and decent fuel economy not drag racing. The cam choice, carb, everything is chosen for the purpose of good street manners.