Sinking Creek 4WD Association

The new yukons are far better than what they used to be. Yukon had alot of their stuff made by Emmbros which is based out of India and they had some serious quality control issues. They stopped using them and if I'm not mistaken began making SOME of their stuff here stateside so they now have an import line as well as domestic (like superior).

I would run them, yukons rear also have a better rep than their fronts.

Hi-9 with at least 35 spline! or you could put a 171 cid motor in and not ever brake anything! And with your truck being so light, you could still do 50mph down the interstate.

I wish I had the coin for a Hi-9, Dave you can start a donation fund for me. Go ahead and make it a Mega Hi9, 40 spline

I might just get a set of Alloy USA 31 spline shafts and a full spool and see how that works. That would only be about $350, and I think it would be stronger than what I have.

Part of my trouble is that every used 9" shaft that I've gotten is already bent, I guess a lot of people think it's ok to haul 2 tons of fire wood on a 1/2 ton truck.

What kind of shafts are you breaking? Stock? Spline count?

Arya Ebrahimi wrote:What kind of shafts are you breaking? Stock? Spline count?

Stock 31 spline shafts, 1.31" dia IIRC. I haven't broken one yet, but I did twist the splines on one pretty good. The Alloy USA shafts I'm considering are made from 1541H steel, not sure what composition the stock ones are. No one seems to make a 4140 or 4340 chromoly shaft for a 9", maybe has something to to with the fact that it is a semi-floating axle and chromo wouldn't be good for load bearing?

VerticalTRX wrote:maybe has something to to with the fact that it is a semi-floating axle and chromo wouldn't be good for load bearing?

Bingo, you need the elasticity since the semi-float shaft and load bearing and not just moment transmitting like full float shafts are.

Alloy makes semi-float dana 60 shafts out of 4140. Chromoloy can generally handle the load of a semi float shaft as well as the torque from what I'm to understand.

Seems to me the increased diameter of a 35-spline shaft would help with bending just as much as changing material, if not more.

I'm not that up to speed on stock 9" hardware. Is it possible to swap in 35-spline SF shafts to a stock housing w/o redoing the ends?

Arya Ebrahimi wrote:Seems to me the increased diameter of a 35-spline shaft would help with bending just as much as changing material, if not more.

I'm not that up to speed on stock 9" hardware. Is it possible to swap in 35-spline SF shafts to a stock housing w/o redoing the ends?

The 35sp shafts will fit in my housing, however there is a chance that they won't fit my third member. I can't recall if mine is a 3.25" bearing third or a 3.062" third. If its the latter it won't fit.

I also found out that the 31 spline shafts are the same diameter as the 35 spline shafts at the bearing/seal area which is where the bending is occurring, so going up to 35sp might not gain me much.

I think I'm just going to put a set of good 31sp shafts in it along with a full spool and call it good, I'd rather be out wheeling than building anyways.

VerticalTRX wrote:The 35sp shafts will fit in my housing, however there is a chance that they won't fit my third member. I can't recall if mine is a 3.25" bearing third or a 3.062" third. If its the latter it won't fit.

I think 3.25" is the aftermarket only third. I've seen them on ebay for sale from circle track cars and such. If you end up going that way, I have brand new 3.25" carrier bearings that you can have from when I did my 3.062" and got an open box deal on a rebuild kit.

I think I'm just going to put a set of good 31sp shafts in it along with a full spool and call it good, I'd rather be out wheeling than building anyways.

Thats what I would do, carry 2 extra shafts, a ton of gear oil and keep running the thing until it gives up. You made it home fine from Harlan with the Exxon Valdez leak up 81. Mine leaks out both seals and from a crack or wear spot in the bottom of the housing too

If anyone around here has tested the strength of a rear 60, it is me.

After blowing several stock shafts, I upgraded to the 35 spline yukons. Haven't broken a shaft since.

I also did as much shaving of the housing as you can without actually cutting the housing. I gained at least an inch of clearance with just a grinder and a grinding wheel.

Defintely go with a 60. I ran my rear 60 stock with 36's and ground clearance wasn't an issue.