Lift kit info

[liftedtrucks4me]

Is it true that if a truck gets to be at a certain lift height that the drive shaft has to be altered? If so what how high is that?

I have a 1986 Ford 150 supercab with the 8 foot bed and I put an old rusted 4 inch lift on it with old 35X12.50s and want to do an upgrade to the highest that I can make it and still pass VA inspection. I was thinking about doing a 8 inch suspension lift and then doing body if I still have room to go all sitting on 39s.

[junior3382]

Yes it is true. And the reason is because as you lift it, you increase the distance between the transmission and the axles. The drive shaft needs to be altered to accomidate this. They do flex in and out to account for suspension travel, but will seperate if the flex demand is too great. There is no "size" limit on a lift, that depends on the truck and usage. Mid sizers could probably get away with stock from 4" and below, where as full sizers may have more or less. hard to determine, however, each "kit" you buy will have it listed in the tech notes if you need to alter the driveshafts or not. It is not as expensive as you think, but definitely a safty issue. If you go with an 8" lift and 39's however, then you will definitely have to alter this for sure.

[75K30]

Typically 6 inches seems to be the "magic" number where driveshats start becoming too short.
Junior mentioned an alteration that has to be made, and that alteration is a new driveshaft. Because the distances between the diff. and the t-case output becomes greater, the driveshaft has to be lengthened, which requires a new shaft. Pretty difficult to stretch the original one, so add a few hundered for new shafts.

That being said, you are attempting to lift a TTB equiped truck quite a fair amount, to run 39 inch tires, and I must say, that you might be under-estimating the overall requirements for such a lift.
For starters, the TTB does not like to be lifted this far. Camber angles change quite a bit with this style front axle, and tire wear is going to be way out of control. The pivot drop bracket is known to be a weak link, and on more than one occassion, has been known for tearing the frame and crossmember where it attaches.
The stock inverted "Y" style steering is also not up to the task of controlling tires this size, nor is the small weak shafts of the TTB Dana44. These are on the edge of failure with 35 inch tires, and 39's will kill parts in a hurry.
39's are also going to require a large jump in differential ratios to maintain the proper mechanical advantage for acceleration, and performance.
Brake lines will have to be replaced, and factory brakes are a little small for this size of tire.
Really, I could comtinue, but this has alredy become a little lengthy.
Just factor in all of the requirements for this type of lift.
There really is more to it than just throwing a kit under there.

[liftedtrucks4me]

So going as high and big of tires i want is going to get really costly. It'll have to wait til I work full time and have money saved up.

Thanks guys

[junior3382]

Anytime that you lift or modify a vehicle to an extent where major parts are raplaced or upgraded, it begins to get costly. Believe me, I have searched and examined every avenue to accomplish this, and no matter which way you do it, money is involved. ONe thing to remember is that if you are going to do it, and then sell it, you never spend more then it is worth, however, if you plan to keep it forever, then the sky is the limit. Once you change the suspension on any vehicle, up or down, the value drops, so as long as you plan to hold on to it until it dies or even longer, then go for it. Just wanted to add that.

[liftedtrucks4me]

I'm hoping on keeping this rig and passing it down to my son so i want to make it perfect.

[junior3382]

Sounds like fun... I wish you the best of luck then.