I am looking to swap the factory axle out in favor of a 14 bolt with 6 lugs and 4.11 gears in my 4WD Tahoe. Instead of regearing what I have which with 32" tires and 3.42 is a little taxing at times I was thinking that going to a 14 bolt would cost a similar amount as a regearbut would greatly improve strength. So what chassis do I need to look for to find a bolt in axle that's the correct width? Even if it's a little wider, that will be fine because I'm running 1" spacers on the back. When I regear the front to match what DIFF would be a good choice for the front? A posi unit or something else? Thanks.

 

I don't know how common the 4.11 ratio was in the 14 bolt obs trucks, but I'd probally try to find one out of a 88-94(?) light duty 2500, the ones with 6 lug axles AND 2500 emblems. Just avoid the cab and chassis truck axles, I believe those stick out WAY too far from your body

 

Does it bolt in minus a U joint conversion?

 

I haven't done it myself so I can only speculate, but I don't see why it wouldn't. My Scottsdale has a 14 bolt from the factory but its never going to see an engine strong enough to break it

 

It has to be from a 4 wheel drive truck otherwise the housing is 3" narrower overall. 4.10 will not be common in the 6 lug configuration. It exists in the light duty 2500's which hung around on into the Vortec era. Certain half tons had light duty 14 bolts as well provided they were heavier duty optioned trucks. Just go junkyarding and you will find what you need.

Forget about a limited slip in your front differential. They do not exist, period for the 8.25" IFS.

And yes it bolts right in with a conversion u joint.

Personally I would go 4.56 with what you have anyhow.... 4.10 will be better than 3.42, but 4.56 will make it more enjoyable to drive.

 

So with a 32" tall tire you are suggesting I go with a 4.56? I was thinking that would be too steep. Is there diff option for the front? I was thinking a posi unit was made

 

As was previously stated, there are no options available for the carriers in the 8.25” IFS differentials. The aftermarket has deemed them just too weak to handle the extra stress. There are options available for different carriers should you decide to install a 9.25” from a ¾ or 1 Ton, but then again it is not a direct bolt-in affair and would require some fabrication to install one. About the only straight forward part of the conversion is the CV axles have the same spline count as the smaller differential and in turn you can use them with your existing ½ Ton hubs. Even the center section has to have some of its stiffening ribs removed from the top of the unit due to being so much larger for clearance in the chassis.

On a side note, I run 4.56’s with basically 32” tall tires and it’s not terribly bad. I turn about 2300rpm at 70mph running down the highway. A 4.30 gear would knock about a hundred rpm off that and help a little, but if I did a somewhat decent amount of highway driving I would probably stick with a 4.10 gear to keep things around 2100rpm at 70mph. Of course 3.73’s would have it at a more fuel friendly 1900rpm at 70mph if you spent a lot time following the white lines. Just about all my driving is around town and my commute to work is no more than 8 miles, so there is no reason for me to run anything less.

 

No 4.30's for 14 bolts either, just 4.10 and 4.56. Too steep...... LoL.... Your highway speed rpm will be slightly less than the stock 2004 in my signature....... No it's not even remotely to steep. The Vortec 350 in your truck might feel like it has some power again offsetting tire weight and diameter correctly.

 

Chevy had a light duty 2500 with 6 lug or a heavy 1/2ton 1500 that also had a 6 lug 14 bolt 9.5.


Don't rule out the 2500 Suburban or truck 8 lugs. In fact the 2500 trucks and suburbans are more likely to have the 4.10's. Just make sure it's a 4x4 even if it's an 8 lug. A 4x4 14 bolt 9.5 should be 67.5 WMS to WMS. If it's 64.5 it came from a 2WD truck. In some cases guys will let the 8 lug 9.5 rear ends go for less because they know the most people want the 6 lug version. If there staying 8 lug they want to upgrade to the 10.5 full floater version.

You can buy new 6 lug axles for $100 each.

Hell I have some used 14 bolt 9.5 4x4 6 lug axles I would sale for $50 for the pair plus what ever the shipping is.

Keep in mind that a 14 bolt 9.5 usually has a drive shaft that is 5/8 of an inch shorter from the same vehicle with a 10 bolt.

HTH