Difranco
05-03-2008, 02:15
My Problem:
After going to tires larger than stock (31" to 33") this change made my speedometer 7% off. Well I lived with this for quite sometime and just did the math in my head for actual speed. However my Jeep is an Automatic ( I love it! ), my transmission shifted slightly off. Well to overcome the loss in power of driving up hill (long mountain passes), which I do a regular basis I decided to have my jeep regeared with 4.88's which was a steep drop from the 4.10's I was running previously. Lastly this just put my speedometer reading 10-15 MPH over actual speed at 55 MPH. This really screwed up my shifting and was definitely eating into my gas mileage.
First attempt at a fix:
My jeep has the trac rock transfer case w (NV241OR) which means that I can't just change a speedometer gear to fix my speedometer but have to take it into the dealership have them program the computer for the correct tire/gear ratio. $55.00 later I found out that they couldnt program my system for the tire/gear ratio I had so they set it to 33/4.56 which helped some but was still not much of an improvement.
The Actual fix:
Well after delving deep into the dark nether reaches of the internet I came across a product that seemed like it would resolve all my issues and life would be grand again. The Superlift Truspeed (http://www.superlift.com/accessories/truspeed.asp) seemed to be about the only option I could find, so I ordered one up from Northridge4x4.com (http://www.northridge4x4.com/).
Install is pretty straight forward. I spent more time planning the install and calibrating the TrueSpeed than actually connecting everything up.
After all is said and done my Jeep's Speedometer reads exactly 60 MPH when the vehicle is traveling 60MPH as calibrated by my Garmin 60CSx GPS unit. I noticed an immediate improvement in shifting, and by the end of the week I will know if my MPG has improved.
Tomorrow its new brake pads, rotors turned, brake fluid flush and Oil change.
Ciao,
Difranco
After going to tires larger than stock (31" to 33") this change made my speedometer 7% off. Well I lived with this for quite sometime and just did the math in my head for actual speed. However my Jeep is an Automatic ( I love it! ), my transmission shifted slightly off. Well to overcome the loss in power of driving up hill (long mountain passes), which I do a regular basis I decided to have my jeep regeared with 4.88's which was a steep drop from the 4.10's I was running previously. Lastly this just put my speedometer reading 10-15 MPH over actual speed at 55 MPH. This really screwed up my shifting and was definitely eating into my gas mileage.
First attempt at a fix:
My jeep has the trac rock transfer case w (NV241OR) which means that I can't just change a speedometer gear to fix my speedometer but have to take it into the dealership have them program the computer for the correct tire/gear ratio. $55.00 later I found out that they couldnt program my system for the tire/gear ratio I had so they set it to 33/4.56 which helped some but was still not much of an improvement.
The Actual fix:
Well after delving deep into the dark nether reaches of the internet I came across a product that seemed like it would resolve all my issues and life would be grand again. The Superlift Truspeed (http://www.superlift.com/accessories/truspeed.asp) seemed to be about the only option I could find, so I ordered one up from Northridge4x4.com (http://www.northridge4x4.com/).
Install is pretty straight forward. I spent more time planning the install and calibrating the TrueSpeed than actually connecting everything up.
After all is said and done my Jeep's Speedometer reads exactly 60 MPH when the vehicle is traveling 60MPH as calibrated by my Garmin 60CSx GPS unit. I noticed an immediate improvement in shifting, and by the end of the week I will know if my MPG has improved.
Tomorrow its new brake pads, rotors turned, brake fluid flush and Oil change.
Ciao,
Difranco