I've talked to multiple people and they've said that lifts can mess up your transmition if you also have big wheels. I want to get a 3 inch lift and 33 inch tires with 16 inch rims on my 1997
Ford F-150. Will this ruin the transmission???

 

Big tires without regearing will cause more stress on the transmission which will make it run hotter,so over time it will wear it down more quickly. Will it happen in a day,a week,a month? Nope. But over years it will. With 159k on my truck running 37s and stock gears,driving it like I stole it every day maxing out the rpms in mud holes a couple times a week my trans is going. Still shifts,just not like it used to. My motor went out before the trans did actually. At the same time,my dads 2wd 01 with street tires got a new trans when it was maybe 4 or 5 years old,so really it depends on the truck and how you drive it.

 

So I assume you are 2wd based on the fact you only want to go to 33's? I believe the ruining of your transmission depends if you have the right gear ratio or not, do you know what ratio you have? There should be a tab on your rear diff that will tell you.

 

You'll be fine with 33s. Is it a 2wd or 4wd though?

 

Larger than stock tires will always put more strain on your drive train.

If a component is week, it could be the straw the breaks the horses back so to speak.