#Th350 transmission how to#
#Th350 transmission pro#

#Th350 transmission pro#

We have a guy locally that builds bulletproof trannys, he's the only guy around that can make the automatic transmissions live behind the pro street cars we race, usually powerglides, but quite a few TH350's in the slower lighter cars, by slower I mean 9's and slower. This shouldn't be an issue for you however. 700 horse in a 4000 pound car is different than in a 3000 pound car as far as the trans is concerned.

#Th350 transmission how to#

Someone that knows how to build trasnmissions for abuse can easily make a TH350 live behind 700 horse, the large factor here that hasn't been brought up is weight, however. So there isn't that great a penalty there as most people think because the difference in the two is mostly in the torque converter which most people swap for a smaller one to raise their stall RPM. A further added benefit of lightening the parts and going billet is that more clutch discs can be added to spread the load out over a greater area to hold better.įinally you asked how heavy is it? Well the TH400 is 60 pounds less than the 4L60E and it weights 166 pounds less than a 4L80E however it does weigh 8 pounds more than the TH350 (all weights are for transmissions only without the filled torque converter). Anyway there are companies that make ultra light-weight parts out of expensive aerospace materials like titanium that can reduce the rotating weight by up to thirty pounds and are stronger by far than the stock parts. I'm surprised no one caught my typo the TH400 properly preped can handle nearly 2,000 hp not the 1,000 as I said (I was thinking of the 4L80E which can only handle about 1,200 horse when built to the max). Luckily just like Camaros there are more people than GM making parts for the tranny.

Additionally, there is an equal amount of force generated when shifting in and out of all three gears.

All of this happens in the short time it takes to shift gears (less than a second if using a shift kit). Keep in mind, when General Motors designed the TH400, it was for an entirely different purpose than racing.įor example, shifting from first gear to second gear, will mean instantly stopping the 14-pound direct drum, which is turning at 84 percent of engine speed, while the 8-pound front reaction carrier starts turning at 50 percent engine speed. This is the reasoning behind having heavy internal parts. The Turbo 400 had to handle the torque of a big-block powerhouse as well as deliver a comfortable and reliable drive. To begin with, there is an incredible amount of inertia produced inside an automatic transmission. Gear vendors states that they have measured parasitic drag before and after on a Spintron and their overdrive units contribute only one additional horse power (way better than the 4L80E numbers). The parasitic drag is predominately centered in the torque converter (the factory changed the angle of the blades compared to the TH350 anticipating more torque input) so which converter you choose will have a big effect upon parasitic drag. Parasitic drag has been estimated at 20 to 40 horse power more than the TH350 (most state at least 20 average appears to be 24hp) dependant upon how much torque is input into the system.

As soon as we get into a 'irresistible force being applied to an immovable object' then you are going to have more breakage problems with a TH350 than you will with a comparably built TH400. That consumes power for this reason the TH400 has more parasitic drag than the TH350.Ĭan a TH350 live behind a 383? Sure so long as we are talking about driving on the street. It has a lot of rotating mass that has to come to dead stop and reverse it's rotational upon each shift. The TH400 is a massive tranny designed by GM to motivate all of the heavy cars in the GM stable with a lot of power (behind big blocks and High Output small blocks). The TH400 can be built to withstand about a thousand horse but at a price. If your thinking of going this route be advised that there is now available a six speed OD tranny from Allison that is supposed to be unbreakable (I said 'NEW' not the old school bus Allison, this one has a computer built into the tranny so it doesn't need an external computer). The TH400 with an OD is called a 4L80E (E stands for electronically controlled by a remote computer).