2000StreetRod
Moderator Emeritus
- Joined
- May 26, 2009
- Messages
- 10,597
- Reaction score
- 331
- City, State
- Greenville, SC
- Year, Model & Trim Level
- 00 Sport FI, 03 Ltd V8
I have a 2000 Explorer Sport with SOHC and 5 speed automatic transmission. When I purchased the vehicle in May 2009 it came with the original Owner's Guide that specifies that the 5 speed transmission is the 5R55E. The trailer towing table in the guide lists 3 possible rear axle ratios: 3.27, 3.55 and 3.73:1. The Certification Label on the driver door lists "D" under TR which decodes to 5R55E for year 2000 and "46" under AXLE which decodes to 3.73:1 open differential. The published gear ratios for the 5R55E are: 1st, 2.47; 2nd, 1.86 (2.47*.75); 3rd, 1.47; 4th, 1.00; and 5th, 0.75. I have not found any documented variations of the 5R55E with different gear ratios. The torque converter can add additional variable gear multiplication or lock at 1:1.
In the fall of 2009 my Sport was performance tested on a Dynojet dynomometer in 2nd and 4th gears. The Dynojet only utilized the vehicle ignition spark to determine engine speed and independently determined vehicle speed. The dyno test results verified the 3.73:1 rear axle ratio but not the 2nd gear ratio of 1.86:1. The dyno derived 2nd gear ratio appears to be about 1.54:1 which means 1st gear is about 2.05:1 (1.54/0.75).
Recently I purchased an X3 Power Flash with custom tune and have accomplished several data logging exercises for the tune development. The PCM receives vehicle speed data from the rear axle mounted vehicle speed sensor that is independent of transmission gearing. The data logs substantiate nonstandard gear ratios for 1st (2.05:1), 2nd (1.54:1) and 3rd (1.22:1) gears. It is my understanding that the torque converter does not have any overdrive capability.
I requested that my custom tune WOT upshift points be based on the standard published gear ratios to maximize acceleration. If I have nonstandard gearing then I may need to change my upshift points.
Has anyone heard of a close ratio 5R55E possibly exported to other countries? I believe that the vehicle original owner was military and may have purchased my Sport outside the U.S. Can anyone think of another explanation for the apparent nonstandard gearing?
In the fall of 2009 my Sport was performance tested on a Dynojet dynomometer in 2nd and 4th gears. The Dynojet only utilized the vehicle ignition spark to determine engine speed and independently determined vehicle speed. The dyno test results verified the 3.73:1 rear axle ratio but not the 2nd gear ratio of 1.86:1. The dyno derived 2nd gear ratio appears to be about 1.54:1 which means 1st gear is about 2.05:1 (1.54/0.75).
Recently I purchased an X3 Power Flash with custom tune and have accomplished several data logging exercises for the tune development. The PCM receives vehicle speed data from the rear axle mounted vehicle speed sensor that is independent of transmission gearing. The data logs substantiate nonstandard gear ratios for 1st (2.05:1), 2nd (1.54:1) and 3rd (1.22:1) gears. It is my understanding that the torque converter does not have any overdrive capability.
I requested that my custom tune WOT upshift points be based on the standard published gear ratios to maximize acceleration. If I have nonstandard gearing then I may need to change my upshift points.
Has anyone heard of a close ratio 5R55E possibly exported to other countries? I believe that the vehicle original owner was military and may have purchased my Sport outside the U.S. Can anyone think of another explanation for the apparent nonstandard gearing?