Drive shafts with 4" Ironman lift

[ceby]

Ok guys, I need some suggestions. Heres what I'm dealing with after mods. (Prior to mods it drove fine with zero issues)
I recently installed an Ironman 4" lift with caster correction plates and 35" AT tires. Took it out and immediately noticed and strong vibration once i got around 30mph and it would lessen the faster i got. It is primarily during accel and decel with some rattle while its floating between the two. First thing I did was take to a shop and had an alignment done, then checked the driveshafts for play. the rear DS had a very small amount of wiggle in the spiders so I swapped them with new OEM. Took it back out and still the same thing. So i pulled the front DS, locked the center diff, took it out and presto! the vibration was gone....mostly. I get just the slightest amount of vibe when i get above 60mph. I noticed that some PO had swapped the front DS joints with aftermarket so I replaced them with OEM, put it back in and im right back to bad vibrations. Next, measured angles, here is what I got:

Front pinion 5.5° up
Front DS 10° up
TC output flange 2.5° down (front DS)
TC output flange 5° down (rear DS)
Rear DS 14° down
Rear pinion 5.5° down

It would appear that the front DS operating angles are way off and the rear DS looks just about right, although with some research I found some that suggest the rear pinion shoud be about 1°-2° lower than the TC output flange to account for rear pinion lift upon acceleration. maybe that will fix that slight high speed vibration im getting in the rear. But to do that I will need to break out the wallet and get new upper control arms.

I have read countless threads on this common problem and have decided on a few possible options without going broke. keeping in mind that this isn't my DD, I swith back and forth with my Tundra. I want to drive it (because it's bad a$$!) just a couple days a week and take it wheeling at least once a month. This is where I need y'all to chime in.

1. Slee part time 4wd, since it drives so well without a front DS in it, less wear and tear on front axle, and I should get better fuel mileage. And not even worry about the stock front DS as I would only lock it in while off-road. I Live in SC and rarely see snow. Side note: I don't mind getting out and locking my hubs if need be.
2. DC front shaft. Do I go this route and take the chance that the vibes do not go away? I have read so many threads of people spending some much $$ chasing this problem. And If I do, how would I go about adjusting the front pinion angle to work with the DC shaft?
3. DC shaft and part time 4wd. (ouch $$$) Is it a bad idea to run option #1 with the stock shaft?

Any advice on other options would be appreciated also. And out of curiosity, will it harm the TC to run it without the front DS and center diff locked? Im not even considering that, I was just thinking about it as I was running 70mph down the interstate checking for vibrations.

 

[LandCruisinMy93]

DC can be made for cheap. Mine was $120 the DC joint came from a 07 tundra rear driveshaft and the slip yoke came from my original front. Some shops say using the tundra DC can't be done, my driveline guy disproved that one quick. And it was cheap.

 

[ceby]

Nice work! I was hoping to avoid cutting my knuckels....why I didnt go above 4" among other reasons.

 

[landtank]

your numbers don't make much sense to me. For instance, how can both the front and rear flanges of the transfer case be pointing down?

 

[baldilocks]

If you have indeed installed the correct plates and your castor is properly restored then you should be set up for a DC front shaft right now.
Look closely and you should see that your front pinion is pointed directly at the Tcase out put.
I have the Slee 4" heavies+Slee castor plates and a custom DC front shaft with no vibes.
I question your rear angles though. My Tcase rear flange is 2 deg down. You report 5 deg down, that seems like a lot. Also, I think you meant that your rear pinion is 5.5 degrees up. In this way both rear flanges would be very close to parallel which is ideal.

 

[DylanICON]

Both TC outputs should be the same as they are physically parallel.

the 1-2 deg lower pinion in the rear is probably referring to leaf springs that flex up under acceleration. with the 4 link I would run those close to the same. the rear seems fine as is.

 

[ceby]

your numbers don't make much sense to me. For instance, how can both the front and rear flanges of the transfer case be pointing down?

While reading up on measuring angles, I was under the impression that angles are referred to up if they progress upward from the front of the vehicle towards the back and vice versa if they are angled down from front to back.

 

[ceby]

If you have indeed installed the correct plates and your castor is properly restored then you should be set up for a DC front shaft right now.
Look closely and you should see that your front pinion is pointed directly at the Tcase out put.
I have the Slee 4" heavies+Slee castor plates and a custom DC front shaft with no vibes.
I question your rear angles though. My Tcase rear flange is 2 deg down. You report 5 deg down, that seems like a lot. Also, I think you meant that your rear pinion is 5.5 degrees up. In this way both rear flanges would be very close to parallel which is ideal.

Yes, you're right about the severity of the angles. But that is due to the truck being parked on my front driveway which slope away from the garage. But I figured all the angles in relation to each other are all that really mattered, so yes the angles noted are all greater than what they would be sitting perfectly flat ground.

 

[baldilocks]

Yes, you're right about the severity of the angles. But that is due to the truck being parked on my front driveway which slope away from the garage. But I figured all the angles in relation to each other are all that really mattered, so yes the angles noted are all greater than what they would be sitting perfectly flat ground.

So how have you decided to deal with the front driveline vibrations?

 

[ceby]

While reading up on measuring angles, I was under the impression that angles are referred to up if they progress upward from the front of the vehicle towards the back and vice versa if they are angled down from front to back.

Both TC outputs should be the same as they are physically parallel.

the 1-2 deg lower pinion in the rear is probably referring to leaf springs that flex up under acceleration. with the 4 link I would run those close to the same. the rear seems fine as is.

i thought that to be odd also when I put the angle finder on the output flanges. I figured they should be in parallel. And that makes sense with the leaf springs. Here is a drawing I made as I went along measuring angles.

 

[ceby]

So how have you decided to deal with the front driveline vibrations?

After talking to slee today, the only real guarantee is part time 4wd. Another idea they gave me was to swap trunion bearings to change the front pinion angle by 3 degree.

 

[baldilocks]

After talking to slee today, the only real guarantee is part time 4wd. Another idea they gave me was to swap trunion bearings to change the front pinion angle by 3 degree.

Have you inspected your front pinion to driveline relationship? I strongly suggest installing the front driveline so you can better see if you have any angle at all at the front pinion U joint, I doubt there is. If I am correct, a DC shaft will eliminate your front vibes. Slee sells a DC front shaft with their 4" and 6" kits not part time kit.
From the factory our front pinion to T-case output is basically a straight shot meaning that the pinion points at the T-case. This is due to the high pinion differential. As we keep castor in the correct range with whatever correction method we choose, the pinion remains pretty much pointed at the T-case output but not visa-versa. This has been my experience and the reason why Slee sells a DC shaft in their taller kits. Unfortunately Slee will not sell a DC shaft separate.
Yesterday another member informed you of how cheaply you could put together a DC shaft as apposed to a part time kit.

 

[landtank]

While reading up on measuring angles, I was under the impression that angles are referred to up if they progress upward from the front of the vehicle towards the back and vice versa if they are angled down from front to back.

it is a lot easier to just read the operating angles. For a DC shaft you want the operating angle at the diff to be 0* +/- 1* and for a stock shaft you want them equal.

I have a thread on here explaining how to read the angle for a DC shaft. You might take a look at it and do the do same on your truck to see how they compare.

 

[ceby]

Have you inspected your front pinion to driveline relationship? I strongly suggest installing the front driveline so you can better see if you have any angle at all at the front pinion U joint, I doubt there is. If I am correct, a DC shaft will eliminate your front vibes. Slee sells a DC front shaft with their 4" and 6" kits not part time kit.
From the factory our front pinion to T-case output is basically a straight shot meaning that the pinion points at the T-case. This is due to the high pinion differential. As we keep castor in the correct range with whatever correction method we choose, the pinion remains pretty much pointed at the T-case output but not visa-versa. This has been my experience and the reason why Slee sells a DC shaft in their taller kits. Unfortunately Slee will not sell a DC shaft separate.
Yesterday another member informed you of how cheaply you could put together a DC shaft as apposed to a part time kit.

With the DS installed you can see there is a little angle at the front pinion. The operating angle is 4.5*, with it being that far off could I assume that Ironman sent me the wrong CCP's? Wishing I would have gone Slee at this point. I do like the Tundra DC shaft idea. I will likely start looking around for a salvage yard. Here is a pic of the front DC at the pinion.

 

[ceby]

it is a lot easier to just read the operating angles. For a DC shaft you want the operating angle at the diff to be 0* +/- 1* and for a stock shaft you want them equal.

I have a thread on here explaining how to read the angle for a DC shaft. You might take a look at it and do the do same on your truck to see how they compare.

Awesome, thanks!

 

[ceby]

Awesome, thanks!

Can you post the link to that thread

 

[ceby]

Have you inspected your front pinion to driveline relationship? I strongly suggest installing the front driveline so you can better see if you have any angle at all at the front pinion U joint, I doubt there is. If I am correct, a DC shaft will eliminate your front vibes. Slee sells a DC front shaft with their 4" and 6" kits not part time kit.
From the factory our front pinion to T-case output is basically a straight shot meaning that the pinion points at the T-case. This is due to the high pinion differential. As we keep castor in the correct range with whatever correction method we choose, the pinion remains pretty much pointed at the T-case output but not visa-versa. This has been my experience and the reason why Slee sells a DC shaft in their taller kits. Unfortunately Slee will not sell a DC shaft separate.
Yesterday another member informed you of how cheaply you could put together a DC shaft as apposed to a part time kit.

Im confused on the straight line between the front pinion and the TC on the stock setup, shouldnt the operating angles be the same on both ends of a single cardan DS to cancel each other out?

 

[baldilocks]

Im confused on the straight line between the front pinion and the TC on the stock setup, shouldnt the operating angles be the same on both ends of a single cardan DS to cancel each other out?

Yes and being a high pinion differential in the front the pinion looks directly at the T case in stock form but stock you are not so that's moot. What matters now is achieving zero angle/bend in your pinion U joint so you can run a DC shaft.
A lot of knowledge can be gained by reading the tutorials on the Tom Woods drive shafts website. Enjoy!

 

[finseeker]

Get slee's adjustable rear upper control arms and use them and a digital angle finder to get both flanges on your rear driveshaft perfectly parallel. Order landtanks front DC driveshaft from ajik and call it a day.

 

[Pin_Head]

While reading up on measuring angles, I was under the impression that angles are referred to up if they progress upward from the front of the vehicle towards the back and vice versa if they are angled down from front to back.

Since the front and rear TC shafts are in line and concentric, the angles have to be the same. One cannot be 2.5 degrees and the other 5 degrees. This just means that there is a considerable amount of error in your measurements. You are going to have to do a better job of getting the angles right if you want to fix this.