Prangley

I am just learning about lifted trucks since I bought one used. My tranny burnt out last week and they are putting a new one in (under the extended warranty thankfully!!).. I am wondering about regearing and was hoping you folks could point me in the right direction.
I have an '06 F-150 Lariat supercrew cab with a 6"BDS suspension lift, 20 inch rims and 37" tires. I will be doing a little light towing from time to time and will hardly ever use the full payload potential of this truck. I also live in Southern Ontario which is completely flat, so no hills to contend with on a day to day basis.
What gears should I go with or do I have to change them at all?? I am going to find out if they had been changed when the mods were originally done or not. I am worried about this new transmission as the last one only had 50,000 kms.
Thanks!

ATOM

4.88's

Prangley

Thanks ATOM, funny you were the first to respond, I almost PMed you this question.

ATOM

4.88's is what most guys run with 37's, you could probably get away with 4.56's however with the weight of 37's on 20's and the fact you will be towing some, 4.88's for sure IMO, also that is the biggest gears you can fit in the front diff, so if you ever wanted to bump up to 38's or 39's you are ready for it.

midwestoffroad

Using the tire calc frormula a 4.30 would be needed to get back to stock ratio. so a 4.56 would be the closest option. a 4.88 will have more bottom end take off power which would help with towing, but the 4.56 would be a good all around gear.