Geographic Void

Ok New here to posting. Got my 05 dodge in January while visiting family for Christmas in Idaho. Shortly after getting the truck I had to put some bigger tires on. Done looks great. Speedo was showing about 5mph slow. Fine for a while as there were no real close dodge dealers in my area. So earlier this summer I was back in Id, and decided to have the dealer fix my pinion factor on my way out of town. Simple right? Apparently not. Now my speedo is 15mph fast. (no gps just pacing with another car. Also trip showed 117 miles at mile post 100 on the freeway.)

Already down the road before I knew it was wrong. Soo

brought it to a Dealer while in the "big city" shopping with the wife and explained what the boneheads had done in Idaho. Waited for 2 hrs and got the truck back. Hit a couple of stores and then back on the freeway. Still 15mph fast What gives. Service department was closed when I stopped back. I called and they gave some lame excuse that it is all very complicated, lots of gear ratios.......

I figured that it was as simple as resetting the Revs per mile based on tire size. Am I wrong. Is it really that hard that it becomes a trial and error test.

Thanks much for the help.

Void

RamWheelsBy4

You are correct it is a simple thing as long as the service department knows what they are doing.

It is about 3 menus deep in the ABS configuration menu. "Pinion Factor" can be set to "other" rpm and saved. This is what my dealer did, took less than 5 minutes. It has been verified GPS mph and OD distance many times.

From the many posts I have seen on this, it seems to be a crap shoot finding a dealer that can do it without hassle and correct.

Good Luck

BigBlue

I had to print out the instructions and hand it to mine and then tell him how to do it. He did mine for free and it's spot on. Now from what I hear he's charging $70-80 to do it.

CTD NUT

You are correct.....2nd and 3rd Gen menu configuration is virtually identcal.....it literally took longer for the tech to plug in the scanner and wait for the connection verification than it did to actually manually reset the revs per mile. Any tech that knows there way around the ABS menus (every DC tech should but obviously doesn't! ) can do this change quickly and easily.....5 minutes, tops. The dealer I took my truck to for this change did not charge anything for this either but on the other hand, if you take your truck to a dealer that can't figure out how to use his scanner, then you will be paying for the tech to stand there and scratch his head. Not very comforting to tell the dealer how to get this done, but as you can see, Big Blue already had to do just that.

Geographic Void

Thanks for the replys

Do you think there is perhaps something that the first tech did to mess it up beyond just screwing up the RPM? It seems odd that both would come out 15mph fast.

CTD NUT

If I were to guess, the first tech simply inputed the wrong revs per mile (by a long shot! ) and the 2nd tech did absolutely nothing to change what the first tech did.

RamWheelsBy4

GV

Did they ask you for a RevPerMile number to use, or did you give them a RPM number to use? My calc says about 615rpm for the 305/70R/17 tire size. They would have had to be off at least 200rpm the wrong way to get to 15mph high I think.

drew03

go to www.bfgoodrichtires.com this is the number of revs per mile that was used to do mine and mine is right on the money.

Nuttymopar

I agree. took my dealer about 15 minutes as I had them do 2 things (Enabled High Idle feature also). They charged me about $ 35 (1/2 hour job). I gave them a number of 601 to set my revs to. I have not checked with GPS but it is closer then it was having 315x70x17 on there.

RamWheelsBy4

Check this post on TDR for what might have caused the original problem. Changing the axle to unkown instead of the 11.5 caused similar problem.

http://www.turbodieselregister.com/f...d.php?t=138223

J BODY

The first one I did took some playing around. Theoretically we are NOT supposed to mess with that data. You won't find and info in a service manual, tsb, or star center on how to correct the speedo for a non stock size tire. Unless they have been informed (read on the web, etc...) most will not know how to do this.

Geographic Void

Thanks all for the info.

RWB4: Great link on the axel. It looks like that may be it.

J Body: If what you say is true it is disappointing to me that they would act like they know and preform the work. If a person doesn't know how to do something then don't do it.

J BODY

.....a person wouldn't last long in the auto tech field if they followed that advise.