Dakotas on Ranchos...HELP.. (PICS)

Ok, so I picked up a set of dakota leaf springs and I was planning on sticking them into my current sagged 3" Rancho pack with a 1.5 inch shackle.

Here is a shot of my jeep before the work:

notice the rear is considerably lower.
Here are the ends of the old rancho packs:

As you can see, the main leaf is supplemented with an equally long leaf that wraps the bushing eye halfway. Then there is a much shorter third leaf that leaves a considerable gap in size. I figured this caused an uneven distribution of weight, thus causing the leafs to sag under the increased stess of the shackle (they never gave 3" anyway)
Here are the rancho leafs (minus main leaf):


And here are the 2 dakota leafs, pus the pseudo-wrap second leaf of the Rancho packs.


Here is the old primary and second leafs of the rancho packs, and the leaf pack of a dakota (minus main leaf) being pulled together:

And here is the end of the new mixed pack. No more uneven gaps:

And here is everything installed ready to ride:

compared to before:



and just for kicks, compared to my Mom's:




As you can see, the arse end is back up a bit, which I'm happy about. I figured the ride would soften up a bit, because I was replacing short stiff leaves with longer ones. I WAS SO WRONG! The initial ride was sickening, as in I literally got sick driving the jeep around the neighborhood. I could count every pebble in the road through my ass. The ride was really, REALLY bouncy, but not in a soft forgiving manner.
The jeep turns corners like a damn ricer though! I railed around 90 degree turns like it was nothing. Almost no body roll at all.
Tomorrow im gonna take that second pseudo-wrapped racho leaf out and see if it doesnt soften things up a bit.

I also must get new shocks or relocate/shorten the shock mounts, as the current ones are pretty much at full extension at static height.

I barely had any vibs before, but now the situation is riduculous. I have a hardcore vib from 15-30mph, and it lets off as I go faster. No biggie, I anticipated working that out.
What I didn't anticipate was the HORRIBLE grinding sound that is coming from somewhere in the jeep's rear that occurs when decellerating, both braking and coasting to a stop, doesnt matter if Im in gear or in neutral. Not just a funny jeep sound, but a SERIOUS grinding that is very audiable outside the jeep (people turning heads from inside thier cars wondering whats the matter) and I can feel it too. It sounds like I left a wrench in the diff or something. It really feels like someting is being torn apart.

The shackels were vertical with the old saggy packs, but now with the increased arch , they have moved towards the rear a bit.I thought it could be the shackles smacking into the bumper bolts at high frequency, but there were no new shiny spots on the shackles indicating contact.

the DS yoke has around 3/4 an inch of shiny area exposed now, not much more than before...

please advise

If anyone has some help it would be greatly appreciated.

Er, I know the shhackle should move forward with more arch, but they just happened to move backwards. Also, the before pic shows the schackle angled backwards a bit, but on solid concrete, the shackle was pretty near vertical.

Additionally, ive ruled out braking components as a source of the grinding.

welded new shock mount studs to the side of the old shock mount tower except put them almost up to the axle to keep use of my 3" lift rancho shocks

going to cut off the old shock towers soon to help with clarence...

yes she is running the stock shaft, just a hair of vibs when accel. showing about an inch of shiney. want to lengthen it soon. The only sound she has is the exhaust hanger rubbing between the spring and skid plate. My xj, on the other hand, has a horrible noise when- not on the gas but not off it either, just at that point when your foot leaves the gas I get noisey grindy noise. Sounds like the drive shaft at the slip yoke. Is there a bushing that supports the tail shaft of the 231 that is worn and with the additional lift is vibrating or grinding? I've got wicked bad drive line angles.

I would check the clearence at the slip yoke at the rear of the t-case, is there any shiny from rubbing?

Clearance between what at the SY and TC? The amount of shiny area on the SY is pretty much the same as before, and the driveshaft looked fine when I flexed it out.

A few questions I am doing the dakota swap next week. Did the ride soften up any? I was going to do the wrap like you did but use all the leafs from the dakota pack and my main leaf. How many leafs did you use out of the Dakota pack?
Now on to your question.
Could you pull the rear drive shaft and drive in front wheel drive to determine if the drive shaft is the cause just a thought. Also I would pull the diff cover and check the gears for chips or breakage that can get expensive if not detected soon enough. Probably time for a diff fluid change anyway. Also check the T-case fluid and let us know what happens
Thanks
DIG IT!

sorry, can't help with your problem, but did you get my money via paypal? i sent it mon night at midnight. your pm mailbox is full. you need to empty it. when are you shipping the springs?
matthew

Changed the diff fluid over the weekend, everything OK. The ride still sucks, but cranking the rancho 9000s up to 3 has controlled the bouncing sensation somewhat. I used all the leaves and the inverted overload leaf (more as a block than anythign else) minus the main eye from the dakota pack.
Taking out the rancho half wrap leaf should be comperable to adding the dakota leaves to a stock pack.


Sarvermr, I need your shipping address, springs are boxed and ready to go.

The sound your describing are your driveline is telling you it's not happy. Check your driveline angles and amount of spline engagement at the splip yoke, make sure everything is hunky dory. It sounds like you might need to consider a SYE before things go south. As for the ride, are you sure your shocks are long enough? If they are bottoming out on extension it would certainly make for a harsh ride. Also, make certain the shackles aren't contacting the shackle box or bumper bolts. Good luck.

Oh, I know my DS angles suck really bad, and I was getting ready to shim out (hardly had a vib before) and vibs that occured with the dakota leaves, just never heard of a major grind (MAJOR, like DW compared to wheel shimmy) with someone going up about 3/4 an inch.
SY engagement is the same as it was before. The solution im going to try out now is to take out the second wrap rancho leaf, move down to a 3/4 instead of 1 1/2 inch shackle, put in shorter springs in front with a small spacer.
Ill see where this takes me and try to shim it out, then try a dropped crossmember, and if all else fails, an SYE.

Maybe your grinding noise is a tweaked backing plate?

hmmmm, I just did the brakes last week, the plates looked OK. I Did have to do a whole lot of grinding/hammering around them to get the rancho spring clips off (they were bolted on) Ill take a look, thanks.

If your thinking about the SYE, just do it. Then you can do what ever you want to the rear. I'm running 6" and no SYE yet, but I have a MT which means longer rear drive shaft. Kinda like a Long Arm effect. Drop the TC and use the longer shackles and an extended SY, that's the best you can do to fix vibes. If it doesn't work just do the SYE, I want to but my pocket book keeps getting tempted by other modifications.

I think half my problems at this point are that my shackles are so long. The pinion before the dakota springs was aimed almost directly at the TCase output (I know I know, perfect for sye). Now the angles are super wacky. I think losing that one racho leaf wont affect height noticeably, and switching to a shorter shackle will drop my pinion down to the point that my pinion and tcase output wil be parallell, or at least close enough for me to shim them that way.
Also, my buddy is doing a 2-4wd conversion, so ill have his DS shortened to a length about 3/4 and inch longer than my current setup and run that.

your mailbox is full again. you're welcome to send the rest back via paypal if you'd like. its not really that big of a deal. if i get them friday i'll swap them this weekend and ship out tues. its a holiday so the usps is closed mon. what is your address?
matthew

Lucas said:

I think half my problems at this point are that my shackles are so long. The pinion before the dakota springs was aimed almost directly at the TCase output (I know I know, perfect for sye). Now the angles are super wacky. I think losing that one racho leaf wont affect height noticeably, and switching to a shorter shackle will drop my pinion down to the point that my pinion and tcase output wil be parallell, or at least close enough for me to shim them that way.
Also, my buddy is doing a 2-4wd conversion, so ill have his DS shortened to a length about 3/4 and inch longer than my current setup and run that.

Click to expand...

I have my pinion pointed at my TC, with the TC drop. It may not be parallel like they say it should be, but that's only with a +/- 3* angle. The big difference is the extended yoke. It's longer at the yoke not on the splined shaft. This allows less bind on the U-joint at the TC.

UPDATE

ok, today I took out the semi-wrap second leaf of the rancho packs and WOW has the ride improved. No more buckboarding, the little stuff is dissapated away and the bigger bumps in the road are not avoided anymore. Its like a whole new jeep. If anyone is thinking about a dakota swap (all leaves except main) I highly suggest it. Ive got a little more lift and the ride quality is much improved over my old rancho leaf packs by themselves (I only kept the main leaf of the ranchos, a stock main leaf isn't that much different).

In addition to this, I stuck in a three degree shim with the fat end forward, pushing the pinion down a bit. This stuck my pinion angle a little over paralell with the Tcase output , but its a noticeable improvement over the original angles I had at the beginning of the post. The first ride out like this I had a noticeable decrease in vibs, but still not as good as it was before I meddled with the leaf packs. Im going to stick in a 3/4 inch shackle in place of the 1 1/2 incher I have now to push the pinion down to what I hope to be almost paralell with the Tcase output.

As for the grinding noise, it was still there!!! I tried braking with my left foot (AW4 auto) while on the gas and the grinding only occured while I was braking hard and the rear end jacked up a bit. Sooo, not the brakes I figured.

I dropped the DS and checked everything out. Ujoints seemed fine. The slip yoke splines were very dry. I drove around the block once in 4HI without the rear DS...man...that was great!. Zero vib, no grind...if a SYE garuntees a ride like that then im saving my pennies over the summer.

Anyway, I cleaned the Tcase output seal , lubed up the splines of the SY with a gob of silver hi temp lube and bolted the DS back in, and replaced the 1/2 quart of ATF that dribbled out of my Tcase when I drove without a rear DS. Driving like this helped the grind a little bit. The noise was still there, but the associated vibration inside the cabin had diminished at all.

So I guess the tiny lift gained by the Dakota leaves pulled the SY out just enough so that when I decellerate, the rear jacks up and pulls the SY out more and it flops around with the vib of the upper Ujoint.

sooo, the solution at this point is to drop the lift a little with a shorter shackle, drop the TC with a dropped Xmember, shim till the pinion and TC outputs are paralell, and get a longer driveshaft to engage more TC splines.

Thanks for everyones help though. It really helped me narrow down the problem and confirmed my suspicions.

WOOHOO,
I just took my a carload of people down to the grocery store and NO GRINDING!!! and only the slightest of vibs if I really looked for them. So the answer at this point is to stick on a full size MT spare on a swing out tire carrier to emulate the weight of passengers and try out the xmember drop. Thanks agiain.

You should get Chevy 1/2 ton shackles. They way they are made produces a boomerang effect so they will swing back farther than straight shackles before hitting the end of the box. Also, if your shackles do hit the bumper bolts, get some washers and space the bolt out as far as you can and still have enough threads in the nut. I will post a picture to illustrate better.


Also, that grinding when letting off the gas petal is your transfer case output or something around there. Mine did that too at when I put on my first lift (Only 3") and a t-case drop solved it. Do you have any shims under the leaves? If you don't put in a 4 degree shim and it should go away, especially if you drop the t-cae an inch. Other than that, you would have to get a SYE.