ive really never herd of that, and i would be really interested in that, can you explain more? any links to the products?
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http://www.gearvendors.com/cg2wd3s.html
They actually don't increase the overall length of the transmission very much, it is much smaller than any transfer case. The 700R4/4L60+80E benefits a ton from them and you get the super cool factor of 8 forward gears. The primary ratios stay the same meaning in a TH400 your 1st, 2nd and 3rd gears don't change. But when you are in 1st the gear splitter shifts up before of the transmission does. So pretty much your new shift pattern would be 1-1.5-2-2.5-3-3.5 instead of 1-2-3. This means a few things. First off, there is no 1st gear difference. So your 1st gear ratio stays the same on take off. But instead of shifting into 2nd gear it shifts into 1.5. This is going to increase vehicle speed further before shifting into 2nd. This means less time outside of the power band, more power right now. Same principal for 2nd and 3rd gear, except now instead of 3rd being the last gear, you get 3.5. So pretty much your TH400 now has the final drive ratio of a 4L80E.
Breaking the numbers down, this is what you will get:
___Gear___-___TH400 W/Splitter___-____6L80E____-____4L80E W/Splitter___-___4L60E W/Splitter
_____________________________________________________________________________________
----1st------------2.48-------------------4.02----------------2.48--------------------3.06
----2nd------------1.93-------------------2.36----------------1.93--------------------2.39
----3rd------------1.48-------------------1.53----------------1.48--------------------1.63
----4th------------1.15-------------------1.15----------------1.15--------------------1.27
----5th------------1.00-------------------0.85----------------1.00--------------------1.00
----6th------------0.78-------------------0.66----------------0.78--------------------0.78
----7th-------------------------------------------------------0.75--------------------0.70
----8th-------------------------------------------------------0.59--------------------0.55
If you ask me, the TH400 w/splitter has a better ratio for a truck than the 6L80E. It isn't jumping as far between shifts meaning less time between gears and more time in the power band. If you want lower, just change your R/P ratio. We know how much stronger the TH400 is. They have kits for the TH350, Glide and pretty much every other domestic transmission. The one for the 4L80E is best in my opinion for a truck but the one for the 4L60E/700R4 has pretty much the same ratios as the 6L80E with a couple extra gears.
By the way, I worked hard on that graph!
They also have us 4x4 guys covered. Kits for the 205, 208, 241 and 243 are available.
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