Stock transmission + 33" Tires

[BettyBlue4runner]

I'm considering having my A340H transmission rebuild and it's gonna run me about $1600 with transfer case. I wanna put 33" tires or bigger if it don't harm the transmission too bad. What do I have to do to the transmission in order for it to handle safely with heavier tires?

 

[fourwd1]

A good tranny cooler and regear the diffs to match the tire size.

 

[4runner_kid]

I would just gear the diff's for the tire size.

 

[BettyBlue4runner]

quick search

so I did a quick search. Is 4.56 good for at least 33" tires? Also is there a kit I can buy to do it myself?

 

[4runner_kid]

so I did a quick search. Is 4.56 good for at least 33" tires? Also is there a kit I can buy to do it myself?

I have 4.56's with in automatic and 32's on mine. I like it, but i'm soon to be swapping in a 5 speed transmission. You will need master install kit's and ring and pinion set's.

 

[fourwd1]

Typically 4.88's are appropriate for 33" tires, but since you have an auto trans, you need to go one step lower, so 5.29's would be the best choice.

 

[fourwd1]

Oh, and a gear install is not for the amateur. There are tools and expertise required that most people don't have. At $250 for a set of gears and $100 for the install kit, times 2 cause you have 2 diffs, that's a lot of $ you could potentially waste.

And an aftermarket tranny cooler is a very good investment no matter what.

 

[Bad_Vision]

+2 good call guys
4.88 re gear!

 

[fourwd1]

+2 good call guys
4.88 re gear!

No, 4.88's is not a good call for an auto equipped truck.

If the OP is going to spend $1000 or so regearing, choosing the correct ratio the first time would be a good idea.

 

[Bad_Vision]

woops missed the auto part.

 

[BettyBlue4runner]

alright so 5.29 is best for 33" tires just to clear things up. And also im gonna need a lift kit. I was thinking the rough country 5" lift? You guys hear anything about that kit? For about $800 I don't think thats a bad deal...

 

[4runner_kid]

The only IFS lift i have had was FJ rear spring's and ball joint spacer's up front, and i was clearing 33's.

 

[evil_motors]

okay not to sound like a total newb here but I am new to 4x4s and i am confused as to why you need to regear anything to run bigger tires? i have loads of friends that switch tires all the time but i dont remember helping them regear anything. is this something that is only on toyota? (my friends have chevy and fords.)

 

[fourwd1]

okay not to sound like a total newb here but I am new to 4x4s and i am confused as to why you need to regear anything to run bigger tires? i have loads of friends that switch tires all the time but i dont remember helping them regear anything. is this something that is only on toyota? (my friends have chevy and fords.)

No, it's not a Toyota thing. On any vehicle if you put taller (or shorter) tires on it throw's the engines operating point out of it's power band. This results in a loss of power, lower mpg, and speedo error.

How much larger a tire you can tolerate before regearing depends on a lot of things, engine size being a major factor. If you have a V8 with a lot of HP the loss isn't as big a deal compared to having a 4 cyl.

How you use your truck also has an effect. If you're a mall wheeler it's not going to matter as much as if you're rock crawling (for example).

 

[evil_motors]

okay that makes sense. so it really is up to user perception. the way i was reading into it made it sound like if you didnt regear you would damage the trans.