Brock

Well, I put the new Nitto Terra Grapplers on over a week ago and have been in the mud..the sand and on highway and love them....but had not been calibrated.

So went by dealer today to get it done...he said it is a $40 charge....so I said go ahead. They got into the ECM........and could not do it. It only listed metric size tires on their loader....and the largest it had was 285x70x17.

While they were in there they asked..."What rear end and differential does this have?"
I asked them why and told them 3.73 with 11.5 inch rear end. He said it was loaded as 9.5 inch rear end and 3.21 ratio....if he was looking at it right.

The loader would not let him manually enter a size though...but it was completely different than an 05 load he said. He said they usually go into the ABS section to do changes....but he found it in the TMS section or something like that. So they set it to 285.....set the rear end to 3.73 and put a 11.5 diff in system. Did not charge me and said they are calling tech support to find out why they cant manually enter Revs Per Mile and it only listed metric sizes...no 31s, 33s, or 35s, etc....

By the way...I searched four different calculators and they all said something different with some usually around 606 revs per mile and others said 625.5 revs per mile. They measured the tire and said it was 105 inches in circumfrence so that made it around 606 revs.....that is with 65lbs in rear tires.

So here is my question...

Any of you 06 guys had your tire size changed for the pinion gears at your dealerships...and if yes, did you put anything larger than 285s on your truck. If you did and they entered revolutions per mile manually....do you think you could find out where they did it in the system and what software version they were using? So I can go by and give my shop the skinny? They did not charge me and said until they got it right it was not right.....


Does it sound right that my truck would be set with 3.21 rear end like that...and what would that have done to my performance if that was in fact how it was set from factory. Would that mean that the miles I show are really like 25-50% higher..........as well. It seemed to be much more responsive on the throttle.....and the overhead was showing much different mpg.


Any help would be appreciated....

picdodge

Just the problem I am having. I had the truck in last week and had the speedo calibrated.I took it on the highway this weekend and it's + 5mph fast. I was told tha same on the Revs., they could only load metric tire size. He loaded a 275/50-20 in mine I believe it is right at 33" so with 35"s I sould be 4mph or so slow. They charged me 100 bucks, its their minimum. I couldn't say much as I did not buy the truck from them, but I will make them get it closer. I would rather have it slow than fast. Probably have to load the 285's too.

If your speedo was correct before the tire swap then the miles should be correct until then.

Boz007

Apparently mkinla's dealer was able to do it mkinla's post . I need to make sure that mine can as im getting ready to put some 315's on mine.

yelloz28

i had the same exact problem tonight. Dealer was going to check on it. Anyone have answers???

GOTMEAT

Nope. Search my posts on the subject. I am still working with Superlift to get the Truspeed working.

RamNu2

I had mine done last week. I was charged $15 dollars and it was called a pinion factor change. I haven't noticed a difference in mileage because of it. I have noticed that i am not flying past people going 65 mph anymore.

yelloz28

what menu did the dealer go under?

yelloz28

Everything I have seen so far says you can't do anything larger than what is already programed into the scan tool. I sat and watched the tech and we couldn't find anything. If you know what menu they used that would be great.

GOTMEAT

Yeah, I would love to give Superlift a big finger and get my money back.