wath do i need to programIf the original programing has 33 tires (275/60r20 ), 3.92 gears and I install tires 37 (335/55r22), gears 4.56 i have the option to programwith the dealer[/align]

 

I have gears on the way and I had that same question.

The speedo is read from a location where the gears wont cause it to throw anything off. From what I was toldyou can change gears all you want and it wont matter. You do need to program in the tire size.

 

thanks for the answer but wath do i gone a tel to the dealer to program for example do i need to put 275/60r20 wit 4.10 gears or something else

 

what year is your truck? They programmed mine for the 35" tires and i do believe they have to program the new gears also if it is four wheel abs because the tranny is electronic and the gears will throw the wheel speed sensor readings off and might cause abnormal shifting. The wheel speed sensor and electronic tranny are the reason i cant put a dana 80 rear end in my truck it has no place for the wheel sped sensor and the senors tone ring is bolted up next to the ring gear in the rear diff!!

 

its an a 2006 4x4 5.7 hemi

 

if the dealer is going to be reprogramming it they should be able to tell you if they need to reprogram it for the gears i am not to familiar with the hemi trucks as mine is an 02 with the 5.9360 in it. It will probably need to be reprogrammed though! otherwise it might shift funny and your speedometer might be off.

 

There is absolutely nowhere in the PCM programming having to do with gears. Any reprogram has soley to do with the diameter of the tire. This can be done by the dealer or by the owner using almost any aftermarket tuner. The transmission shifts by a predetermined engine rpm, these can be changed with certain tuners, but again really have nothing to do with the gears...

 

thanks for the answer
ok but my dealer dont know wath to pragram because they only have the litle aplications like 33 with 3.92 or 33 with 4.10 wath you suggest

 

Your dealer doesn't have to change anything for the gearing, it simply has no effect. What they do need to change is for tire diameter. A technically competant technician should be able to figure it out, but just in case what they'll need is the Rev's per mile for your tire. There are formula's and calculators all over the internet to help you figure this out. Also, many tire manufacturers give this to you - see this link for Toyo as an example: http://marktg.toyotires.com/file/18971.pdf - you'll notice in the column to the right it gives Revs per mile....