I recently put new gears in for the oversized tires and the speedometer is WAY off. I need to get a recalibrater for that, but I know you can get these built in to a programmer. Do they make a programmer for a 96 Ram with a 318? I've seen them for newer models, but just wanted to see if anyone had seen one for my year model.

 

I believe JET chips make a reprogrammer for tire and gear changes for your truck. I also have a 96 so let me know how it works out if you get it.

 

You can not correct speedo error on a 96 with a programmer. They only work if your speed sensor is in the diff which didnt happen till 98 or later.
For a 96 the speedo gear inside the trans on the drivers side will need to be changed. Think it was about 10 bucks at the stealer.

Post what your tire specs are and gears so we can figure out what your final ratio is

 

I've got 33X12.50's on it with a 4.56 ratio in the differentials.

 

33s with a 456 give about 423 final ratio
410 should be around 38 teeth I believe so you probably want 39-40 teeth. The stealer should be able to help on the tooth count.

 

What do the 98+ owners do? Am I really THAT far off with 285's? According to the door pillar, the truck's supposed to have 245's (riiiiight) but came from the store (new) with 265's.

 

RM
I went to the dealer, and they can't get any bigger than 38 tooth which is what comes on the 4.10's. I'm bumping up to a 35 in a month or so, so will I be good with that? Are there any aftermarket companies that carry this? I don't know the formula or I could figure it out myself. Thanks for the help thus far!

 

With 33s your speedo error is 7.2% and at 65mph on the speedometer your actually doing 70mph.
Going to 35s will have your speedo off by 13.4%
35s will give you about a 396 final.

If you stick with the 33s, go with the 38 tooth gear
35s, will need either 35 or 36 tooth which should have you real close.

TMS Bill, your 285s are 33s so you have the same speedo error
You can get a Superchip or Hypertech and fix the speedo error on your 98.