FJ40 rear axle shims

[Brian/99uzj100]

Thank you @Brian/99uzj100. Looks like I remove the axle side...pull the driveshaft apart, rotate 90 degrees then reinstall the sleeve. If I am a tooth or so off, will that affect it?

You won't be off, it'll go together right as rain.
I just swapped mine front to back, cleaned it up, and re-greased it. I'll paint it when I change out the U-joints, but for now they have no play.
I also had to pull it apart and rotate it 180 to get all of the grease fittings on one side per the FSM.
Before:

After with grease fittings corrected:

Hijack over...

 

[Groucho263]

That's exactly what I needed...pictures for people like me that eat crayons. I noticed you don't have shims in there...do you have a lift on it? Did you drive it...and notice a reduction of any vibration?

 

[Brian/99uzj100]

That's exactly what I needed...pictures for people like me that eat crayons. I noticed you don't have shims in there...do you have a lift on it? Did you drive it...and notice a reduction of any vibration?

Ha! I'm a visual learner myself.
I took it for a test drive and it's a little smoother.
I had shims on the back before, but got a bad vibration on deceleration, so I removed them. That was when I learned my driveshaft was out of phase, probably a year ago.
Correcting the driveshaft phase really smoothed things out.
I checked all of the angles from the diagram on my prior post (only with an angle app on my phone) and they're within spec.
My rig has a 2.5" OME lift with 4 degree steel shims in the front for caster correction.

 

[Groucho263]

Ok, finally had time to pull the DS off and correct it per the instructions above....and re-greased. It's way smoother until about 45mph then I notice a vibration, but can't tell where it's coming from...it's slight. If I put it in neutral and coast...the vib seems to go away. I'm assuming with these older trucks that there will just be some vibration?

 

[mrldcty]

It appears to me from the pic that your shim needs to be reversed (or removed) so that the pinion is as close to parallel with the TC angle as possible. Have another look at post #13 above.

 

[peesalot]

The vib you feel at 45 is from the slip splines. I bet it goes away above 45 ? Mine is same way, I have had a few d-lines and new joints, it always did it to some degree. I finally had the slip spline replaced and it still does it as you decellarate thru 40 - 45 a bit. My 40 is soa so my d-line is a bit longer but I have the pinion more or less pointed at t-case, stock flanges/yokes clearanced for max droop. Take the slip apart and put drum bake axle grease in there, helps the vibs.

 

[69FJ40HILIX]

OK, so I think I have a pretty good understanding of the need for caster shims on the front axle. I am doing a 4" Skyjacker lift with shackles on both front and back that are 1 1/2" longer than stock. What about the rear axle. Obviously, caster is not an issue, but pinion angle is. Some say that the pinion should be parallel to the transfer output flange (e brake in this case). In that case, the high part of the shim would point towards the rear. Others say that the shim should increase the pinion angle so that there is less likelihood of the universal joints binding or the shaft vibrating, so the thick part of the wedge will be on the front. Opinions?

The pinion shaft should point as best as possible directly at the transfer shaft output. A double cardan joint is also adviseable on steep angles, this aloows equalization of angles to keep the universals from binding. If you install one it should be at the transfer case end of shaft, not at the axel. Sitting on its suspension, not in action, the layout of parallell shafts works for stock suspension but in travel (rough terraine) the axel dropping to it's lowest point and heavy torque applied will put a major strain on the U-joint / pinion shaft output. Woody's shafts in Ogdon Utah can answer your questions and provide a shaft if you need a quality one. TomWoodsDriveShafts

 

[Groucho263]

@mrldcty, this is super confusing. I originally add the new springs with no shims...and got a pretty bad vibe in 2nd/3rd gear. Then I added the shims in the other way (fat part facing the shackle), but the vibe was really bad...couldn't get out of 1st gear. So, I changed them and now have just that slight vibe.

@peesalot, yeah, the vibe lessens above 45, but it's still there. I put a little grease in the slip when I r&r'd it. Probably not enough?

@69FJ40HILIX, had a buddy tell me about these the other day...I might try one.

 

[mrldcty]

I have been chasing vibs in my truck as well. I put on the OME 2.5" lift springs and measured the geometry, which was pretty out of spec, and I had a lot of vibrations (not really drivable). Then I went through a number of individual steps with the following results:

1. New U joints - very noticeable reduction in vibs. This really surprised me because there was no noticeable play in the joints before I replaced them.
2. Phased my drivelines, which had gotten out of phase when I replaced the U joints, user error - slight improvement.
3. Placed shims in the rear to bring the pinion down (i.e., fat end of shim pointing aft). - More improvement... now driveable.
4. Rebuilt and replaced the rear axle and diff (installed lockers) - this quieted it down quite a bit more (even though the stock diff wasn't out of spec).

Pointing your rear diff at the TC will only work if you have a cardan at the TC, which you don't.

I recently took my shafts in for balancing and I'm about to put them back on when I install my rebuilt front axle and diff (lockers again).

I also played around with the shackles (swapping front to rear and back) and removing/adding a leaf in the rear to get the stance right. I have added a LOT of weight to the rear of the truck (4plus carrier, tool boxes, gas cans, bike rack, spares, etc...), so the leaf is currently back in with the long shackle in the rear. I have a 4 deg shim in the rear and 6 deg in the front (for caster).

Once it get her back on her feet, with the new diffs front and rear and the freshly balanced shafts, it will be interesting to see how she drives. Hoping for smooth through to top speed.

HTH... it has been a longer journey than I expected, but it will be worth it in the end knowing the geometry isn't waring sh!t out to quickly!

 

[69FJ40HILIX]

@mrldcty, this is super confusing. I originally add the new springs with no shims...and got a pretty bad vibe in 2nd/3rd gear. Then I added the shims in the other way (fat part facing the shackle), but the vibe was really bad...couldn't get out of 1st gear. So, I changed them and now have just that slight vibe.

@peesalot, yeah, the vibe lessens above 45, but it's still there. I put a little grease in the slip when I r&r'd it. Probably not enough?

@69FJ40HILIX, had a buddy tell me about these the other day...I might try one.

I had a vibration as others stated also, the Cardan eliminated it 100%. My rear shaft is 18" long and at a radical angle. I am running a auto trans 4WD Toyota Hilux turbo diesel.

 

[Groucho263]

Holy smokes. You have done a lot of work!
I would assume if I add the carden I would take the shims out..,or leave them in?

 

[69FJ40HILIX]

Holy smokes. You have done a lot of work!
I would assume if I add the carden I would take the shims out..,or leave them in?

My opinion I dont like things that are not fixed in place. I cut off the axel leafspring base plates, turned the axel pointing at the transfer and then rewelded and installed new shaft. Talking with many people who hill climb and rock crawl their advice is what I did. I'll post a few pictures after I put it back up in the air. This is the front underhood, older but shows the amount added under the hood.

 

[mrldcty]

With my small, 2.5" lift, my DS angle is just about at the limit, so I considered a cardan. I would think any more lift than that and a cardan would definitely be needed. But I need to run it to really see what's what... should have her on her feet by the weekend so I can get the diffs broken in properly and jounce her a bit to check the bump stops and springs and tire clearance.

 

[69FJ40HILIX]

10/4 , the figuring it out is frustrating but in the end you have a buletproof dependable machine. What gear are you running, stock 4.11? Do some research on the double cardan joint and you will see the reasoning behind having it. I worried about the angle also, have hte same lift plus body 2" and Woods explained a lot to me when I did it.

 

[mrldcty]

Not sure if you were asking me or the OP... but what the heck: Stock gears for my truck are 3.70, so stayed with that for now. Am seriously considering an Orion TC though, which will gear me down to 4.11 in low range, and keep the 3.70 in high range so a get a good crawl speed plus the higher highway gears. My rig is still pretty touchy above 55 MPH though. I need to drive it (only put a few hundred miles on it since I got it last July) and get used to it. I think my steering box may need to be tightened up some. I plan to corner weigh it soon too, to see if it is seriously off (although not sure what I would do about that if it is).

 

[69FJ40HILIX]

Good plan, the front suspension parts (tie rod ends etc) are really strong but I found mine was losey-gosey at the pitman arm ball so I replaced the spring and ajusted the tension on the ball which helped tremendously. The arm has a cotter pin in it, a slot to hold the ball socket in place and holes all around so you get 1/4 increments of tightening adjustments +/- .

 

[peesalot]

@mrldcty, this is super confusing. I originally add the new springs with no shims...and got a pretty bad vibe in 2nd/3rd gear. Then I added the shims in the other way (fat part facing the shackle), but the vibe was really bad...couldn't get out of 1st gear. So, I changed them and now have just that slight vibe.

@peesalot, yeah, the vibe lessens above 45, but it's still there. I put a little grease in the slip when I r&r'd it. Probably not enough?

@69FJ40HILIX, had a buddy tell me about these the other day...I might try one.

Grease is vary vaque - I mentioned drum brake axle grease because its a LOT thicker

 

[ukboneman]

Ok, finally had time to pull the DS off and correct it per the instructions above....and re-greased. It's way smoother until about 45mph then I notice a vibration, but can't tell where it's coming from...it's slight. If I put it in neutral and coast...the vib seems to go away. I'm assuming with these older trucks that there will just be some vibration?
View attachment 2998133View attachment 2998134

I am no expert for sure, but to me it looks like that slip yoke is so extended that it's about to come apart. There is almost no overlap. I would think that as it becomes extended, there is more "wobble" or vibration. Should that shaft be lengthened?

 

[69FJ40HILIX]

Grease is vary vaque - I mentioned drum brake axle grease because its a LOT thicker

I am no expert for sure, but to me it looks like that slip yoke is so extended that it's about to come apart. There is almost no overlap. I would think that as it becomes extended, there is more "wobble" or vibration. Should that shaft be lengthened?

Good point, but he is not sitting on the suspension and I wonder what it is when the weight of the vehicle is on the leafs? Is that a stock yoke or replacement? Where the picture was taken the suspension is at it's zero point, when collapsed (weight on it) what is the length? I understand it should be appx. 1" inserted when the load is applied, no telling unless it was hands on IMO.

 

[Groucho263]

I am no expert for sure, but to me it looks like that slip yoke is so extended that it's about to come apart. There is almost no overlap. I would think that as it becomes extended, there is more "wobble" or vibration. Should that shaft be lengthened?

I was wondering the same thing actually. That's with the weight on the suspension...it's not on a lift. Wondering if I just need to go to Tom Woods Cardan...but holy crap...almost $500 for that rear DS.