Hi, I recently bought a 99' 250 w- an 8" fabtech and 36" tires. I am currently changing the rim/tire setup and possably going with 37 or 38s, still unsure. I don't want to increase tire size if it will be to hard on my truck. I had to get a full tranny rebuild right after buying my truck but the gearing is stock. Should it be changed?

 

When you say "stock", what was stock for your ride? This truck with stock 4.30 gears could survive, but will be hard on transmissions if it has 3.73's.
Are you running a gas or diesel engine?
Gas engines will like a little more gear than a diesel. Youmay consider gears in the 4.56 to 4.88 range. This should get you back to factory ratios, and give your truck the mechanical advantage it needs to stay alive.
I ran 4.88's with 36" tires on an 02 gas SD, and was pleased.

 

It is the v-10. It's kind of slow off the start, but I am thinking of staying with 36's. Could anything be damaged if I keep stock gearing? Also, how much would it cost to gear the front and back? I've been looking around and I think my truck has 3.73 gears, but am not sure.

 

Is changing the gears something that I could try myself? I have no experience in this area, but I found some gears online for a good price and it would save me a lot of money to change them myself. Could anyone give me a brief overview on what would need to be done and how hard it is?

Thanks

 

First timers should stay away from this area. Setting up gears properly is a very critical and percise job.
failure to set up a set of gears will ruin not only the gears, but if metal starts to shed, will compromise the bearings as well.
I am not saying it is difficult, but it will require some supervision if it attempted by a novice.
Everyone starts somewhere, so I am not being critical here, just that one wrong measurement, and you will have a pile of junk parts. This will mean that you will have to buy all new components and have a pro install them anyway.
Save the hassle, and spend the money to get it done right.
I am not a plumber, but can sweat a copper joint. This still does not make me a plumber. When my house has a plumbing problem, I call a pro.
I am a very mechanical person, and build my own rigs. I can set gears up, and have done several but still I choose to pay a pro to set up my gear sets.
Just like paying a plumber, I pay a differential pro to set my gears up.
You can save a bit of money by doing this work yourself, but get it wrong, and you end up paying more in the long run.
I am also not crazy about buying gears by mail unless they are brand new, and I am very particular about the gears that I run.
Some cheap gears may not have the same quality as some others. This is an area where you get what you pay for.
Gear runout is very critical, and a cheap set may not be dead straight. tight spots, means that the gears can drag, and maybe the lash has to be set a little wide. That sacrifices gear strength because the pinion cant index the ring properly, and you may end up with a noisy set, or a set that could break if tasked.
Too many things that could go wrong, by trying to save a few bucks.
Heak, there are probably 100 other things you could save some money on, and the gears might not be the place to do this.

Which ratio did you decide on?

 

Thanks for the reply. I'll definitely have a professional do the job when I get it done. I think I'll go with 4.88's. It may be a little while before I have it done because of the cost, but I think 4.88's is the way to go with my truck. Thanks again.