Duffs four link and pinion angle

[Casey835]

I'm installing my 351 with 4r70w/AA adapter and I've noticed the rear pinion angle is way out(needs to point up more). I just noticed this so there are a lot of unknowns at this point. It's looking like I may have to cut the two rear brackets off and the truss to get it all set back right (that's a lot of cutting). If I do, I will take advantage of the opportunity and move axle back at the same time. I'm throwing this out there in case I'm missing something and basically want to make sure I'm on the right track. The four link has been installed for several years and had no issues with anything. I plan to call Duffs and consult with them as well.


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[garberz]

Now you have a good reason to buy a Tru-Hi9.

Mark

 

[Yeller]

do you have it sitting at the correct ride height? If everything is positioned correctly there should be enough adjustment to fix the pinion angle, but if the ride height is not correct its all a mute point. With the length of the drive train, you may not be able to get enough down angle out of the driveshaft, making a hi9 mandatory, shouldn't be but might.

 

[Casey835]

Currently the roll cage and body minus the doors are sitting on the frame with wheels on it sitting in the shop. I was planning to throw a few hundred lbs in it and see what that does. Oh and the motor all the way back to the transfer case are sitting on the frame also. Does anybody know how much you can turn those rod ends out safely?


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[Yeller]

Yeah your light for sure. the easy way to determine how far you can go you need to pull them out and mark the shank measuring from the end the diameter of the shaft. I usually figure 3/4-1" shank is safe at 3/4" threader in and 1-1/4" good at 1" threader in.

Also install your driveshaft with the suspension fully mocks up and let it fully droop to make sure the driveshaft does not bind

 

[5001craig]

My top links were not correct. Monster Mike told me to that I could cut the welds off and extend them to get the correct pinion angle. That or they would send me a new set of upper links. It was easy to extend them. There was a lot of adjustment built-in to them after I cut the welds.

If you look closely (zoom-in) at this pic you can see how much I extended my upper links for the correct pinion angle. Has a lot to do with how you fit your truss to the rear-end. But you find this out after it's fitted. Was an easy mod for me.

And don't look at the TMR rear support. It's coming out on advice of Advance...

 

[Casey835]

I seem to remember just barely being able to get everything set up correctly with the lengths of the links when I originally installed it. Hey Craig when you cut the weld did you just pull that out some or did you have to add that piece in? Thanks guys, I'm feeling a lot better about all this, wasn't looking forward to cutting all those welds.


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[5001craig]

I seem to remember just barely being able to get everything set up correctly with the lengths of the links when I originally installed it. Hey Craig when you cut the weld did you just pull that out some or did you have to add that piece in? Thanks guys, I'm feeling a lot better about all this, wasn't looking forward to cutting all those welds.


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I did not add anything. There was a bunch sticking in the tube and had plenty. There were only two that I cut--top links on the back. Mike asid they'd send me new (longer) links but it was really easy to cut the two welds, get them where I wanted them and re-weld them.

 

[Casey835]

I had a chance to take a quick look at it today, looks like it should be easy to fix now that I know I can do that.


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[Mmflpa]

Have you tried calling anyone over at Duffs? They are amazing when it comes to helping out with stuff like this

 

[68rustbucket]

My top links were not correct. Monster Mike told me to that I could cut the welds off and extend them to get the correct pinion angle. That or they would send me a new set of upper links. It was easy to extend them. There was a lot of adjustment built-in to them after I cut the welds.

If you look closely (zoom-in) at this pic you can see how much I extended my upper links for the correct pinion angle. Has a lot to do with how you fit your truss to the rear-end. But you find this out after it's fitted. Was an easy mod for me.

And don't look at the TMR rear support. It's coming out on advice of Advance...

What's wrong with TMR support?

 

[Monster Mike]

well I was gonna get involved but Steve and Craig got everything handled! lol ;D

After I installed our 4 link on sniper for our 2015 Christmas charity I noticed we needed to give an extra inch of length to the upper links to allow for proper pinion angle.

The latest version of our 4 links are dialed in for the ultimate install and ride experience. Especially now that we are offering a bolt in sway bar kit exclusive to the Duff 9" 4 link setup as an add on.

 

[5001craig]

What's wrong with TMR support?

It holds the transfer case in one place case too rigidly. The engine mounts and adapter mounts are a triangle. When you support the back end of the transfer case (as I did), the engine and transfer case still want to move but the TMR support holds the transfer case in one spot. I actually had a leak between the adapter and the Atlas that seemed to be getting worse. It was AFT that was leaking--not Atlas lube. I called Atlas to discuss this leak and they said to remove the support. They said it's not needed. Unless you're running something crazy which they said I'm not even close to.

And not to totally hijack this thread, I have truly been impressed with the Duff 4-link kit (extended radius arms too). It's very beefy--like I'd make it if I knew how to do it. And Duff's/MajicMike's support is impressive. He truly wants your experience with Duff products to be a great experience. I'd give them 5 of 5 stars. ;D

 

[Casey835]

well I was gonna get involved but Steve and Craig got everything handled! lol ;D

After I installed our 4 link on sniper for our 2015 Christmas charity I noticed we needed to give an extra inch of length to the upper links to allow for proper pinion angle.

The latest version of our 4 links are dialed in for the ultimate install and ride experience. Especially now that we are offering a bolt in sway bar kit exclusive to the Duff 9" 4 link setup as an add on.

Hey do you think I could use the same method used to correct pinion to also push wheel base back an inch or so or would that be pushing it? Of course I would have to do all 4 links and maybe extend both ends.
By the way I love the ride of my Duffs 4 link suspension, it took some work to dial things in but it rides and handles just as good as my f350. May have to check out that anti sway setup. I used to call and ask about it from time to time until Brian said it had been put on the back burner then I gave up.

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[Monster Mike]

Hey do you think I could use the same method used to correct pinion to also push wheel base back an inch or so or would that be pushing it? Of course I would have to do all 4 links and maybe extend both ends.
By the way I love the ride of my Duffs 4 link suspension, it took some work to dial things in but it rides and handles just as good as my f350. May have to check out that anti sway setup. I used to call and ask about it from time to time until Brian said it had been put on the back burner then I gave up.

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In theory you could extend the wheel base that way. I wouldn't recommend it though because the lower link ends cannot be cut and slipped out an inch. They only slip in a total of 1.5".

Our anti sway bar setup is really sweet. for the 4 link kits made before January of 2013 and all the 1 ton 4 link kits we do not have a bolt on truss bracket for the sway bar that works yet. The bracket that is in the kit could easily be modified to work though.

Thanks for the awesome feed back, glad you are happy with the ride!

 

[Casey835]

Ok thanks! I'll just leave the wheelbase where it is. My four link is older than 2013. I'll have to check into the bracket that needs to be modified.


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