Delta VS Radius Arms (1 Viewer)

[Surfdc]

A slight growl between accel and decel is driveshaft angle. Throw the bumper and winch and batteries on to bring the front down and see if that relaxes the front shaft angle.
And check the rear angles too!
This video is excellent at explaining it all. Good luck.

 

[BillyGoatMTB]

A slight growl between accel and decel is driveshaft angle. Throw the bumper and winch and batteries on to bring the front down and see if that relaxes the front shaft angle.
And check the rear angles too!
This video is excellent at explaining it all. Good luck.

The bumper winch line battery all that's already on the front, I brought my 80 to West Coast driveline in West Sacramento and the gentleman there doing drive shafts for 40 years took the angles himself.

My concern was maybe something got damaged with a growling so bad, like maybe I strained the front output shaft bearing on the transfer case but it does not seem loose.

I'll probably pull the front drive shaft and bring it back to West Coast driveline for a rebalance I'm going to ask him to check it not at a steady state spin.

 

[baldilocks]

Thanks for this. My front diff flange is facing in the correct direction, up towards the Tcase 2ish degrees, however the Tcase flange is also facing up not parallel 2ish degrees down towards the diff. I'm still researching this but it looks to be the reason some 80's need a DC and some don't.

My front driveshaft wasn't happy, so I played it safe with a DC added to the new factory one.

I still get a slight growl right between acceleration and deceleration I'm still trying to hunt down. Any ideas?

I don’t know your lift height or your castor reading but 2* up pinion flange seems like it may be a bit low causing more than 1* of angle induced into the forward U-joint. Ideally, to run a DC shaft perfectly smooth, there should be zero angle/bend on the front joint. This means that the pinion flange and drive shaft tube should be at a right angle to each other. The pro’s say that up to 1* off is usually acceptable.

This assumes that your driveline is balanced and U-joints are good.

 

[BillyGoatMTB]

I don’t know your lift height or your castor reading but 2* up pinion flange seems like it may be a bit low causing more than 1* of angle induced into the forward U-joint. Ideally, to run a DC shaft perfectly smooth, there should be zero angle/bend on the front joint. This means that the pinion flange and drive shaft tube should be at a right angle to each other. The pro’s say that up to 1* off is usually acceptable.

This assumes that your driveline is balanced and U-joints are good.

When i had the DC Made the delta between the front diff flange and drive shaft was 0.5 degrees, it is my understanding as well the DC works well under 1 degree between those two.

 

[Surfdc]

When i had the DC Made the delta between the front diff flange and drive shaft was 0.5 degrees, it is my understanding as well the DC works well under 1 degree between those two.

@baldilocks beat me to it!
Pull the front shaft and drive it. If vibs are gone, your angles are still too extreme, regardless if they are within a tolerance.

 

[alia176]

Also, the famous growl can come from the rear DS under decel or the transition period when the rear axle housing is rotating just a tad under load, no load conditions. Sometimes this points to worn out rear UCA & LCA bushings as they're allowing too much rotation.

Try this, fill the cargo area with 300# of weight and see if the GRRRR still occurs during the same exact gas pedal input.

 

[BlackMud]

I'm also facing the growl between acel. decel. after installing the Delta radius arms, 3" dobinsons lift and custom extended driveshaft. My next try will be to replace the lower and upper arms (extendable) to fix the rear geometry. One question though, by hearing the growl, does that mean that the diff can be damaged if driven a certain amount of miles with the growl going on?

 

[Surfdc]

I'm also facing the growl between acel. decel. after installing the Delta radius arms, 3" dobinsons lift and custom extended driveshaft. My next try will be to replace the lower and upper arms (extendable) to fix the rear geometry. One question though, by hearing the growl, does that mean that the diff can be damaged if driven a certain amount of miles with the growl going on?

Keep it simple at first: try pulling the front shaft and driving. If growl is gone, then go further after the front geometry.
If the growl is still there leave the front shaft out and start with rear shaft geometry.

 

[BillyGoatMTB]

^This

I also have a Dobson 3-in lift and have been chasing driveline vibes.

My front transfer case output flange was pointing up not down toward the differential, I had a custom driveline shop in Sacramento build me a double card in shaft which helped dramatically. I still have a tiny bit of growl right between acceleration and deceleration. It has not worsened though after a few thousand miles.

After talking to the driveline place they said bring it back in the gentleman there has been doing drivelines for 40 years he took the original angles off my 80 series himself. He says now we're going to check Castor.

I realized my shaft could also be misaligned left to right so I'm going to look at that and see about adjusting my panhard bar.

This has been a long road for me I burn up a brand new factory drive shaft in just a few thousand miles, they warranted it for me and I brought that brand new shaft to the driveline shop. They kept the front and the slip yolk and made up a DC in the back.

If you crawl under there I use a kline digital magnetic angle finder, pay close attention to what the angle is positive or negative meaning up or down.

Tom woods has some fantastic videos on YouTube about driveline angles.

I keep reporting back to a different thread about vibrations hoping to help the next person that runs into it.

 

[BlackMud]

OK, thanks for the info. Very useful.

I must say that along with the Delta radius arms I also installed both front and rear adjustable panhard bars with extended links on the rear and slee blocks on the front to level everything. The growl still persists. Other than 35 tires, I don't have anything extra installed like bumpers, top tents etc. that could add weight to the rig. All stock... My last try was to install a custom extended tom woods ds but still, the growl is there.

So after reading the last posts, I have a question. What does it mean when one says to pull the front shaft or how to do it? This is my first time dealing with this and any help would be appreciated. Will also check some videos from tom woods, their sales service was great and I definitely recommend it.

 

[Dusten]

OK, thanks for the info. Very useful.

I must say that along with the Delta radius arms I also installed both front and rear adjustable panhard bars with extended links on the rear and slee blocks on the front to level everything. The growl still persists. Other than 35 tires, I don't have anything extra installed like bumpers, top tents etc. that could add weight to the rig. All stock... My last try was to install a custom extended tom woods ds but still, the growl is there.

So after reading the last posts, I have a question. What does it mean when one says to pull the front shaft or how to do it? This is my first time dealing with this and any help would be appreciated. Will also check some videos from tom woods, their sales service was great and I definitely recommend it.

He means remove the front driveline and drive without it.

Growl is gone, the front is the issue.
Growl stays, the rear is the issue and the front might be.
Fix the rear. Then reinstall front. Growl is back? Now fix the front.

 

[BillyGoatMTB]

^This

@BlackMud if you have a CDL you can drive around and definitely with one drive shaft either front or rear.

Example when I pull my front drive shaft she's silent.......

What everyone is saying is pull the drive shaft lock your CDL and drive it it the vibrations gone you've isolated the issue.

I will say I have suspected possible wear on my transfer case output bearings but there's no play no matter how hard I wiggle. With that said there's no way we could replicate the forces being generated from the vehicle with our bare hands.

As mentioned, my front DC made a huge difference, but to me if there's still a tiny bit of vibration it's just going to keep getting worse.

 

[clydeepants]

Yea I cut that front part too on mine , which is how Slee has you cut them, I just pulled the plates and put new arms back in original holes and have had no issues or cracking or loosening, it has worked for me and I know other people

@ajax1 Just wondering how the radius arm set up is holding up with the "notch" cut out of the arm mounts on the axle? I just received my arms and I'm on the fence about whether or not to re-weld the material back on to the mounting bracket.

 

[clydeepants]

And the obligatory delivery photo. These radius arms are stout, I ordered the 3L flavor.

 

[residualboulders]

And the obligatory delivery photo. These radius arms are stout, I ordered the 3L flavor.

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So how do you determine if you need the long or not? I've just installed dobinsons 2.5 lift (ended up closer to 4" from old worn out springs). I need to correct the caster. Was going to use the bushings with various caster settings but leaning towards just replacing the arms.

 

[clydeepants]

So how do you determine if you need the long or not? I've just installed dobinsons 2.5 lift (ended up closer to 4" from old worn out springs). I need to correct the caster. Was going to use the bushings with various caster settings but leaning towards just replacing the arms.

From what I read, the "L" version will move the axle approximately 1" forward. This option is typically for those who run larger tires (37"+) and want to move the axle forward to provide more room between the front fender pinch weld area and your tires. I believe caster correction is the same between the regular and "L" versions, someone can chime in if I have that incorrect.

In your situation, sounds like you gained 3" lift (+1" over the sagging old springs). If you don't plan to run larger than 35" tires, the "regular" version of the arms would do the trick.

 

[alia176]

@ajax1 Just wondering how the radius arm set up is holding up with the "notch" cut out of the arm mounts on the axle? I just received my arms and I'm on the fence about whether or not to re-weld the material back on to the mounting bracket.

Be sure to get a caster reading before and after the arm install, if possible

 

[ajax1]

@ajax1 Just wondering how the radius arm set up is holding up with the "notch" cut out of the arm mounts on the axle? I just received my arms and I'm on the fence about whether or not to re-weld the material back on to the mounting bracket.

Been that way for couple years no issues might depend on how much was notched out though as well

 

[Sandy Cruiser]

@ajax1 Just wondering how the radius arm set up is holding up with the "notch" cut out of the arm mounts on the axle? I just received my arms and I'm on the fence about whether or not to re-weld the material back on to the mounting bracket.

I couldn't stomach having the notches there. I was worried that where the two cuts meet would eventually form a crack, especially without a stress relief the Slee plates provided. Used some cold rolled flat stock I had laying around. Welded both sides and then grinded them down. Hardest part was crawling under the truck and vertical MIG welding laying on my back without the ideal hand positions, something I'm not very good at.

 

[Kabanstva]

I see you have a 93/94 version for the 2/4/6” arms but not for the 3/5” arms. Why is that?