Hey guys,

I've got a difficult situation here. So I have been chasing this for some time throwing parts at it and have gotten nowhere but worse. Here's the symptoms:

1. Intermittent wheel hopping sensation while rolling on throttle 35-40 mph. Corners, and while straight. Felt through seat only.
2. Bad high frequency vibration that starts about 50 mph, crescendos at 63, and tapers off a bit over 70. This issue is quite a bit newer than 1 but may be related. Felt through seat only as well.

Troubleshooting 1 (and other things that have happened since it started 2 years ago)

All new front end and shocks. Aligned. New tires. All new rear suspension (springs shackles shocks). New front wheel bearings. New right rear axle shaft bearing and seal. Brakes have been done a couple times in the front once in the back. New u-joints in the driveline. None of this changed issue #1.

Issue #2 started about a month ago and has been steadily getting worse. Over the weekend I pulled the driveline so see how those u joints were doing. The rear one spun a cap in the yoke and the front felt tight. No play in slip joint. Seemed pretty screwed up so I had a new driveline made today. If anything #2 got worse and #1 is still there. I placed the rear axle on stands. Ran it up to 60 mph vib is there so #2 is definitely in the back half of the truck. Took wheels off and held drums on with lug nuts. Still there. Took drums off. Still there. Disconnected driveline from transfer case, finally gone. So its somewhere between the new driveline and axle shafts.

Not sure what to do next.

It's a 99 Ranger super cab, 4x4 offroad package. Has the beefier axle casing with the 8.8, 4.10 gears, and LSD. I believe the tires are 31 or 31.5s. All stock except the new driveline. 5 speed.

Darn thing feels like it's going to come apart on me.

 

Are the U-joints properly phased/clocked ? Notice on the bottom drive line how the yoke is 90 degrees out of phase, the slip/spline joint was put together wrong

 

I have to admit I didn't pay attention on the new DL but I had checked it on the old one and they were properly phased on that one. I will check the new DL tomorrow. I did see balance weights on the new DL.

 

New DL definitely phased correctly

 

Talked to the driveline guy. I trust his work and wanted to get some input. He is suggesting that maybe the pinion flange is worn and not centering the DL or something else in the diff is going. He referred me to a rear end specialist who I set up an appointment on Tuesday to have them look at it. This evening I will loosen the bolts at that flange and see if there's play in the DL side around its center..

 

Dropped it off with the rear end guy today. See what he says. I bet everything in there is toast. 230k miles and it's been contaminated with metal in the past when one wheel bearing started munching through an axle.

 

Ok guys, everything is junk at this point.

Pretty much every bearing is pitted, including the newer one I installed some time ago. The shims are spun and the clutches are bare metal. So pretty much the only things left I want to reuse are the pinion and ring gears, and the housing.

I have it back and driving for now as the guy wanted me to get my own diff and axles. So let's trick it out!

Ok, I dont mind spending a little more to do this right as a) I dont ever want to have to worry about it again and b) this truck will become "toy" status in another year or so and I'm going to build it up a bit then.

So I already know I'm going to put a truetrac in it. The rear end guy seems to think I can get moser 31 spline axles that will fit in this thing to replace the 28 spline. However all the info I find on the net seems to conflict with this because I would need a bigger axle tube. Anybody here know what's true here? I will probably call moser tomorrow and ask anyway.

Would a c-clip eliminator kit be worth the extra money?

Also, he is not confident replacing all this will solve high speed vibration but the throttle roll on shimmy might go away as it could be LSD chatter or the carrier moving around. He pointed out that it was weird how he couldn't hear any of the bearings while it was going down the road but as soon as he had it in the air it was loud

 

Well I hope someone around here is reading this, been rather quiet. Moser doesn't offer Ranger axles after 97, so it will be a custom job and he needs a bunch of dimensions. Not looking forward to pulling a shaft to get the dimensions, maybe I will buy and return a cheap axle from the auto parts store. He can make 31 spline to fit without changing bearing size

 

I would think it would be easiest to get a Ford Explorer Rear Axle and put it in.
A little extra work needed to install but some come with Disc Brakes, Posi, all have 31 spline axles.
There is a kit to save on reversing the spring perches and makes this ALMOST a bolt in.

IMHO... there no way to make a OEM 28 spline rear axle assy, run 31 spline axle without increasing the bearing size; there are a couple of ways to do that quickly, one is the Explorer rear end and the other is find a 2002 or a 2003 Off-Road or LvL-II, their rear housing are already setup for 31 spline axles.
I am guessing someone in the aftermarket could supply a housing to do it too but $$$$$... if your pockets are deep !

Good Luck,

p.s. Check your transmission mount, if it is worn or even partially torn you will get vibes too.

 

I'm aware of the exploder axle swap, there just aren't any in my area. I live in a fairly well off region so there's lots of guys modding vehicles here grabbing up all the good parts. I couldn't even find another 5 speed when I needed one.

I dont do anything that crazy, though a mild 5.0 swap may come down the pipes some day. If the guy at moser can make a 31 spline axle to fit my small tubes then I'm all for it. I have to have chrome molly axles made custom for this thing anyway since moser doesn't offer them off the shelf (only the narrow track 97 and older rangers apparently) so there's no cost difference in going 31 spline if possible. Otherwise itll be 28 spline. They dont charge that much to make each axle. It's less than the craptacular replacement kit from shmoriellys.

 

If you think you may be doing a 5.0 swap in a year or so, start looking for a 95 - 01 5.0 Explorer now, doesn't need to be pretty, just complete, you're going to need a lot of the parts anyway.

EDIT: just checked autotrader, there's one for $1500 runs and drives 108K miles on it close to me.

 

Thanks but its farther out than that. I need to take care of some debt and get a commuter first. The Wife and I only have a car each right now hence the ranger is a daily atm. But we will get there someday. Mines rust free, clean underneath, and decent paint/interior so it's not going anywhere. Plus I have a bit of history with it that makes it sentimental.

 

AND the Explorer will give you your axle !

One thing to think on, and I am not sure about, will a 31 spline differential work in the smaller housing ?
It might be the same as the large housing but I don't remember.
Also, the smaller wheel bearing, you loose some of the strength of the axle if the parts are smaller !

Luck on the project.

 

As a mechanical engineer I'm well aware that the smaller bearings will be a bit weaker however the axle is usually the weaker link when it comes to catastrophic failures. I'm doing what I can with what I have for now. I figure if I get an exploder donor later I can sell this axle for likely a profit.

As far as I can tell the diff doesn't change in any way between 28 and 31 spline besides the openings for the axles. It's still an 8.8 which a lot of the dimensions are limited by the ring gear size. It could prove me wrong however. We shall see. Going to call in my order for the shafts at moser on Monday.

 

Provided Moser with the dimensions today. He swears up and down he can do 31 spline without changing the bearing size. I guess they do it all day long for mustang's. About $400 shipped with screw in style wheel studs. Not a bad deal if u ask me. Have em next week

 

The question that pops into my mind is 'IF the axle diameter for the 31 Splines is a larger OD than the 28 Spline OD, I can't understand how they will get the same 31 Splines in the smaller axle as the larger. If they can get the 31 Spline count, what will the spline size be, the same as the 31 spline shafts or smaller, finer, AND what size will the bearings be ? If the ball of the bearing are smaller than the standard 28 spline axles, then how will they stand up to the wear and tear ?

I know it is me, trying to double guess what is happening here, and Moser is a good Company, so I for one would really like to know what the finished product turn out like, what the ball bearing size will be, and in turn what the long term turns out to be.

Not trying to dampen the project, just really curious about this ?

 

You're ok I'm questioning it a bit too. I noticed that the splines and majority of the axle inside the axle tube is noticeably smaller in diameter than the bearing surface on the 28 spline. My assumption is that the 31 spline, while larger than 28 spline to fit all 31 splines, will still be smaller than this bearing surface.

 

Oooooooo Moser. Note that the axle shaft comes much closer to the diameter of the bearing race area than what is usually seen on 28 spline axles. I tried to take a photo with all splines in there to prove its 31 spline but that's kinda hard to do. I noticed the bearing area has a much smoother surface finish than the shmoerielly replacements I put in there before.

Also included photos of the eaton truetrac cuz car guy pr0n

 

So the axle in the picture was custom made?

The carrier is a stock assembly, yes? New LSD, new springs, new disks....and all this fits your axle housing?

How much if you don't mind me asking? Thanks

 

Hi, yes I dont mind answering questions.

Yes they are custom axle shafts. It should be noted that Moser does not have off the shelf shafts for 98+ Rangers. Therefore they needed to be custom made anyway, and there was little to no additional cost going to 31 spline in either the carrier or the shafts. So why not? Also the screw in studs were $10 more. I dont know if I'm supposed to provide cost on here so I'm only going to say I paid ABOUT $400 for these.

Not stock style carrier. It is an eaton truetrac that does not contain clutch packs made for Ford 8.8 rear ends. It is a limited slip differential utilizing a couple sets of planetary helical gears to bias torque. It works better and smoother, and does not require friction modifier. Cost was ABOUT $560 prior to tax.

In theory this should all fit my housing that originally came with the Ford 8.8 and 28 spline axles. A point should be made that it required the custom shafts to make it work. I have an appointment with a rear end shop to install everything on tuesday.

 

Good to hear it is working out.
The rear posi will help in the mud.

Enjoy !

 

Word is that my truck has been assembled and test driven. Will pick it up for the long drive home and report back later.

He mentioned that now that the rear end is quiet he can hear marbles in my transfer case when running it in the air. Ruh roh

 

IMHO... I wouldn't jump to any conclusions or have additional work done until you have a chance to drive the truck.

If the Transfer Case is worn out, it might be easier and cheaper to just replace the Transfer Case with a used unit.

Ltr

 

Yeah I know it. He doesnt do transfer cases anyway, he only builds rear ends.

I've attached some pics of the bearing surfaces. One of those axle shafts was only 9 months old (shmoeriellys replacement kit). The other is to my knowledge the original ford shaft

So, it's a LOT better. In the last week it had started rumbling at 45 mph which turned my seat into a massage chair by 65. Now between 60 and 65 there's a vibration somewhere that I can only hear, not feel. May even be coming from the front. I had a shock absorber issue up front (kyb shocks were beating the crap out of my tires, too heavy duty) that may have cupped my front tires a bit. It's due for a rotation so I will start there.

I'm ASSUMING if something was up with the xfer case I would easily feel it in the shifter?

Also the wheel hop is completely gone now

 

Morn'n,

The races show some wear and pitting, definitely needed replacement and of course the bears, not bad but needed to do it all, which you did with the new axles. The axle's bearing mounting surface is rough, pitted too... but even and the bearing show even wear, not too bad, but to me don't show signs of a spun bearing.

Are these vibes at 45+, new ones or what was ?

The Wheel Hop... ??? Wheel hop has nothing to do with the rear axle rebuild, more of a shock thing, did you replace your rear shocks, or maybe loose bolts that got tightened with the Housing re-install ?

Did you go through the frontend to determine if there are worn parts ?

I think you said the driveshafts are new so those should be good.

My '88 STX/5.0L, had a slight clunking at take off and sometimes stopping and a slight vibration that I could not find, talked to mechanic friend of my, we put the truck on the lift and he pushed on the transfer case to find the trans mount was torn over half the way through. Replaced it with another I had laying around and gone was the clunking but the vibrations turned out to be U-Joints, funny how things turn out.

Ltr