After reading about IFS problems in this forum as well as hearing about them, I've been thinking I should upgrade the IFS in my truck. I have a 95 K2500 6lug with a 4" ProComp suspension lift, 3.73 gears and the 14 bolt SF rear, but I just found out it only has the 1/2 ton IFS rather than the slightly beefier 3/4 ton IFS. I am currently running 33x10.50x15 BFG's but I am thinking about going to a 255/85/16 BFG mud terrain. After checking the tire and wheel weights from what I have now and what I want to go with I will adding about 9 lbs. of weight per tire/wheel (about 71lbs. to 80lbs.). I am concerned about breakage in the diff and CV joints with this added weight. I have also thought about down the road sometime possibly addding a body lift and even taller tires which would cause even more concern. I know for the ulitmate 4X4 setup I should probably do the straight axle conversion but I'm shying away from that option due to cost and the rougher ride. What I'm wondering is if it is possible to do a swap to a 3/4 ton IFS, and what it would involve, as well how much weight it could handle? Thanks.

I considered this about a year ago, and found out that the cost would be similar to that of a straight axle conversion. This swap also adds minimal trail advantages and durability. In addition, it is as complicated of a swap as a straight axle. Therefore, I would suggest going with the straigt axle upgrade if you need to do a swap. Your IFS, as is, should be able to handle up to 35" tires if properly maintained.

This being said, I still want a straight axle conversion in the next few years.

Nich Kenny
'89 K1500 350/700r4

How do you have a 3/4 truck, with a 1/2ton IFS???????[img]/wwwthreads_images/icons/crazy.gif[/img]

A 3/4 ton IFS is only marginally stronger then the 1/2 ton [img]/wwwthreads_images/icons/frown.gif[/img]. Honestly I wouldn't mess with it at all, it should be fine with all the tires you are talking about!
(just don't jump it![img]/wwwthreads_images/icons/smile.gif[/img])
Of course you will have to replace some front end parts from time to time, but that's true no matter what front end you have.
MORAL = Don't worry, be happy! [img]/wwwthreads_images/icons/laugh.gif[/img][img]/wwwthreads_images/icons/smile.gif[/img][img]/wwwthreads_images/icons/shocked.gif[/img]

Scooby, the 6-lug 3/4 ton's have the same front end as a 1/2 ton. However, they all have Z71 torsion bars (stiff) and a SF 14 bolt rear. The heavy 3/4 ton has a bigger front end, just like your 1-ton.

Nich Kenny
'89 K1500 350/700r4

So the "heavy 3/4 ton" has 8 lugs? (so thats where these 14bolt, 8lug, SF rear ends are coming from, that makes sense now)

It sounds like the regular 3/4 ton is what they used to call a "heavy 1/2 ton", and the "heavy 3/4 ton" is what a 3/4 ton always was. (did that make sense[img]/wwwthreads_images/icons/crazy.gif[/img])

What you said makes sense, because my previous truck was a 6lug 3/4 ton, and when I lifted it the guy at Fly-N-Hi said that the 3/4 ton front end was basically the same as the 1/2 ton, and that the main difference between the two was the rear axle and suspension.
Is the 3/4 ton frame different from the 1/2 ton? (88 and up)

I am pretty sure that the 3/4 ton frame is a bit more beefy than the 1/2 ton frame. It has a higher payload, tow capacity, etc.

The light 3/4 ton is essentially a "Heavy Half." I think they began making heavy 1500's again around '94. They had a 1/2ton frame with SF, 6-lug 14-bolt rear.

From my experience, the light 3/4 ton is a very strong truck, noticeably tougher than a 1/2 ton.

Nich Kenny
'89 K1500 350/700r4

The best IFS upgrade I know of is a Dana 60. You can upgrade your IFS to the driveway[img]/wwwthreads_images/icons/wink.gif[/img]

90K5

One thing I would like to point out there about converting your truck to the 3/4 IFS. All that is really going to change is just the Diff. Its a little larger and will take more torque. As for doing the swap, I don't think it would be worth it at all because your still dealing with those Sh$tty CV-Joints and thats where the problem is always at if anywhere at all on a IFS truck.

I too am one day going to be doing the solid axle swap, when im not sure anymore. Things are happening right now with me and I have the chance to buy some land so I might just have to sell my Sport again[img]/wwwthreads_images/icons/frown.gif[/img] and see if I can get lucky and make some money on it again this time[img]/wwwthreads_images/icons/smile.gif[/img] but I do that weather the conversion will be in my present truck or one of my future trucks I am going to do it, and the right way when I do. Why pay for things more than once? I learned that after lifting my IFS truck!!!

Good luck...Ryan

Thanks for the input everyone! I think I'll just stay with what I have for now, and if I can afford it later on, I may do the straight axle conversion. By the way, has anyone ridden in or driven a truck that has been converted? I'm curious as to how rough of a ride it is, although I'm sure it would depend on different factors, such as how much lift it has and what tires are being used. In regards to the CV joints Ryan, I think that the 8 lug 3/4 tons do have stronger ones. At least that's what it said in the June 2000 issue of 4x4 Power magazine. As they put it: "the CV joint axles are also uprated". I suppose they could be wrong too. Does anyone know for sure?, I'm just curious.