2.84 Ratio Input Carrier Kit
Part No. 77284-K
” 700R4 / 4L60E “Power Gear “
“The Next Big Thing”. PATC has developed a new 6 pinion planet gear set for 700R4 / 4L60E transmissions. This will be the biggest thing in 700R4 advancements in years. These will have a 2.84 to 1 first gear, 1.56 to 1 second gear, 1 to 1 third gear and .70 to 1 overdrive ratio. This close ratio 700R4 gear set will have a 11.72% less RPM drop between 1st and 2nd than the wide (stock) ratio gear set. In other words the close ratio gear set will only have 88.28% as much RPM drop as the wide ratio gear set. This is what people have been asking for, for years. These will work on any 4L60E type transmission without a gear ratio error code, if the PCM is modified. The carrier is made from E4340 billet steel and the pinion gears are 9310 steel. With the billet sun gear made from 9310M steel. This gear set is used to reduce torque multiplication / rotating speed in the transmission in first gear. This improves track applications that overpower the rear tires upon launch. This is common with numerically high final drive ratios. Now you will have a choice between the wide ratio or the new close ratio gear sets. In first gear this close ratio gear set has a 7.2% numerically lower final drive ratio. It has been reported that the 2.84 gear set could lower your quarter mile time as much as 4/10 of a second over the 3.06 gear set. This gear set has been in research and development for over one year. You might ask why 6 pinion gears. The answer is because high horse power motors can eat the small needle bearings up in the pinion gears. The solution is to spread the load over 50% more needle bearings and at the same time building the planet gear set out of a higher grade steel. The first 50 are in production now and the approximate release date is May 2009. We have finished the testing in our test truck with the following findings. The gear noise in manual low is reduced by at least 50% compared to a stock OEM planet gear and at full throttle there was no noticeable power drop on the 1st to 2nd shift. Testing will begin later this week in an 1100 horse power C5 Corvette. The car runs 9.56 seconds now. Nothing will be changed but the front planet gear then tested to see the difference. Testing should be completed by 6-1-2009.
Here are the test results from the weekend of May 30-31, 2009. Both where run for the base time then nothing was changed but the front six pinion planet gear then retested to determine the time difference.
The first car is a C5 Corvette with an 1100 horse power blower motor. The best time with the factory planet gear was 9.56 and the time with the new 2.84 six pinion planet gear was 9.25. This is a whopping 3/10 of a second faster in the quarter mile. The time would have been even better if the 3-4 clutch wouldn’t have been slipping. Perhaps as much as 1/2 second better then the factory gear ratio.
The second test was with a 460 horse power all-wheel-drive Chevy Cyclone. The best time with the factory planet gear was 13.10 and the time with the new 2.84 six pinion planet gear was 12.90. This is a whopping 2/10 of a second faster in the quarter mile. There was 300 to 400 less RPM drop on the 1-2 shift with the new gear ratio. This truck didn’t have a problem with tire spin on take off because it has all-wheel-drive. The 2/10 of a second was picked up on gear ratio change only, not on take off.
Update 6-3-2009: Three more reports have come in with 3/10 of a second or more off of their E. T..
This gear was built for the 1982 on GM 700R4 family of transmissions only, that includes the 700R4, 4L60, 4L60E, 4L65E and 4L70E model numbers. For drag racing purposes the 700R4 has too large of a gear ratio spread between first gear and second gear resulting in too large of a RPM drop between gears resulting in a large torque drop (loss). With the new 2.84 gear (1st gear ratio) there is approximately 500 less of a RPM drop on the first to second full throttle shift depending on the RPM of the 1-2 shift point. This gear change also results in a 4% less RPM drop upon the second (intermediate gear) to third (direct drive, 1 to 1 ratio) shift.
The purpose of this gear is keep the torque at a higher point on the torque curve when shifted to second gear from first gear resulting in a faster elapsed time in a quarter mile. The front planet gear controls the gear ratios of first and second gear. The 2.84 to 1 gear ratio in first is accomplished by using a larger diameter sun gear and a smaller diameter pinion gears. At the same time the pinion gear carrier and the sun gear are made from a higher grade steel to handle motors with higher horse power and torque levels. In addition one or two additional pinion gears are added (total of six) to spread the load (torque) over a larger area and to accommodate more pinion gear needle bearings. (The OEM stock front planet gear set has 4 or 5 pinion gears.)
In testing it was found to result in at least a 3/10 second improvement in elapsed time in two wheel drive cars and at least a 2/10 second improvement in elapsed time in all wheel drive cars. As an added bonus the 2.84 first gear ratio has less tire spin that the 3.06 original equipment first gear ratio making 2WD cars faster on take off. For the purposes of the 700R4 transmission the 2.84 gears set would be called the close ratio gear set and the 3.06 original equipment first gear ratio would be the wide ratio gear set. A wide ratio gear set would be better for towing and a close ratio gear set would be better for racing. There are other transmissions with 2.84 first gear ratios or six pinion gears but not for the 700R4 family of transmissions.
Fits 2006-Earlier reaction shafts only
- Requires use of OE bearing 8642191 “or” 24217327 (not in kit)
- Only 2006-earlier reaction shafts can be used with this kit. This shaft has an extra step on the bearing surface. The outer step on the bearing riding surface will be either 2.600” or 2.650 diameter.
- 2007-Later reaction shafts CANNOT be used with this kit. This shaft does not have an extra step on the bearing riding surface. The outer step on the bearing riding surface will be 2.490” diameter.