Pirate 4x4 banner

Axle and Suspension redo. 3 link/4link Tru Hi 9

75442 Views 166 Replies 57 Participants Last post by  Frank TJ
10
First time posting any pics of my work. Be gentle just a novice fab/welding guy.

I grenaded my stock 30+ year old Ford 9 inch center section on Black Sheep Blvd back in early November. I got good service out of the stock case but after 30 years the metal was fatigued enough and finally failed. After careful consideration I decided to repair the damaged 3rd member and sell this axle complete. I am now the proud owner of a Crossed Up Offroad Hex housing:



I orginally wanted a Spider 9 housing, but I wanted to purchase one with the bearing cups already attached and basically ready to weld brackets on. Spidertrax only sells the housings bare. After trying to give 2 of Spidertrax's vendors my business and never receiving a return call I went with the Crossed Up housing. Basically the same exact thing as a Spider 9. The only upgrade I made was 3/8 wall axle tubes.

For quite a while I have been wanting to get rid of the RE long arm skidplate. I bought one of the orginal ones that did not have the removable center section. Getting to my tranny and t-case was quite a chore with having to remove the entire suspension to gain access. This seemed like a perfect time to make a new tranny crossmember and removeable skid plate. Here is a shot of where I am on that. The crossmember still needs paint and the skidplate needs finally trimming and paint also.







With removing the RE skid I no longer had mounting points for my control arms. I decided on the front 3 link brackets from Poly Performance and the rear 4 link brackets also from Poly with Johnny Joints:









Here are a few shots of the completed front 3 link.:









For my rear axle I will be using a Tru Hi 9 with 5.38 gears, 35 spline spool, and Strange Engineering 35 spline shafts. This is the only part I am still waiting for delivery on. With all this work stemming from a failure of a 30+ year old stock Ford case I decided I better do something about the front 3rd also. Picked up a Strange nodular gear case, Moser aluminum pinion support, and some new 5.43 gears from Summit for my front axle.


Will update with more pics once the rear end is complete
See less See more
1 - 20 of 167 Posts
Comparable to a Spider 9 or Diamond housing.
Your fab skills look fine, but that pinion angle looks a bit crappy.
Looks fine to me, as you can tell by the pics and the springs it looks like the axle is dropped and the jeep is propped up.
The rig is on jackstands with the springs supporting it. Look at the upper link, it is already heading up. If it was at droop, that link would be in the engine at compression.
Why isn´t the Hi9 up front and the LP 9 out back. Much stronger that way!!!!!!!!!!!!
Curious as to why you put the upper on the drivers side? Typically I have seen vehicles done by Poly with them on the passenger side.
Why isn´t the Hi9 up front and the LP 9 out back. Much stronger that way!!!!!!!!!!!!
More clearance for the pinion at the rear to keep it from bangin on rocks.
Looks good Frank. Any idea how the new brackets changed your geometry compared to the RE Long Arm stuff?
Do the Poly brackets tuck up better than the old brackets?
What's the thickness on the skidplate?
I talked with Poly about this and they said there is no magic side, just whatever side it fits better. I went with the drivers side because:
1. My exhaust is in the way on the passenger at full compression.

2. With having a 9 inch front axle I could simply weld the link bracket to the top of the housing. I used a shorter bracket to get the seperation then a 8"+ tall bracket on the passenger side to get the same seperation.
Your fab skills look fine, but that pinion angle looks a bit crappy.
Not done dialing it in. It may change, but that is pretty close to what I was running with the RE longarms. Never had a problem in 3+ years.
Looks good Frank. Any idea how the new brackets changed your geometry compared to the RE Long Arm stuff?
Do the Poly brackets tuck up better than the old brackets?
What's the thickness on the skidplate?
Shell,
All of the bind that was inherent in a RE front radius arm setup should be gone. Other than that the links are about the same length and mount in approx. the same locations.

The poly brackets are about the same distance below the frame rails has the RE long arm mounts were, apporx 1 inch to Centerline of JJ.

Skidplate is .25 plate. Kinda heavy, but lighter than the RE plate.
why dont you put the lp in the back and get a Great Lakes offroad pinion guard
Why isn´t the Hi9 up front and the LP 9 out back. Much stronger that way!!!!!!!!!!!!
Not sure why you say that. All the comp buggies have Hi 9 front and rear. Hi 9 in back mainly for clearence. My front is also only 31 spline so I didn't want to buy a Hi 9 for that when my ultimate plan is a front 35 spline 609.
Get it, Frank. Sounds good.:smokin:
Ultimately, He will have a HI-9 up front as well, but he already ordered this one as 35 spline. He's not ready to go 35 spline up front yet. True Hi-9's are more than strong enough to survive back there.
No way I would run a Hi-9 in the rear, I have seen and heard about too many blowing up. If he has a 4.0 then he will probably be OK since the rig is light, but if it has a bigger motor then it is not gonna last. I have seen two of them go and have heard of another 4 or so go. All in the rear.
I followed that thread too. His stuff's not weak by any means. I'd run it back there no worries. Some people can break anything.
Of course now I'm getting emails from people asking why this fella has broken 4 sets of gears and what the problem might be.

In response to that I am making this post.

We have sold Hi9s to over 300 different people. Three people (1%) have broken gearsets as of today. That leaves 99% running them without breaking gears.

Of the three one went to a low pinion and has since either stripped or broken multiple ARBs and twisted 35 spline axle shafts and is currently switching to 37 spline D60s. The other 2 have broken multiple gears sets. It was suggested to ALL 3 to run a GM 14 bolt as that should hold up to their needs.

A reasonable conclusion is that the Hi9 is strong enough for 99% of the people but NOT everybody.

As to why they broke, I was advised by wngrog in the past not to give my thoughts in the matter.
1 - 20 of 167 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top