Discussion in 'Early CJ5 and CJ6 Tech' started by tripilio, Jan 4, 2019.
Wallet is not the issue...(said no Jeep owner ever!)
As it is I have barely any knuckles left!
Don't forget that you have to torque it to 100-120 ft.#. My whole Jeep tweaked a little with that one. Removed and reinstalled about 3 times, gets easier each time. The first time was the worst due to the "special snap ring". Herms instructions are a huge help.
Yesterday I opened the rear cover and, they match! Now I can start rebuilding the front without worrying about wasting my time and money.
If you do choose to put in an OD. Be sure to measure the OD to case very carefully and shim as necessary, according to instructions. DAMHIK
To all the wise people out there: I already started to rebuild my front axle (Dana 25) and in every video I have seen the preload of the pinion is tackled first, shimming it until the rotational torque is in spec. Then the carrier is mounted to adjust backlash and pattern. My understanding is that the backlash is adjusted with the shims under the rear bearing, which moves the pinion in and out. My question is: once my pinion preload is adjusted and I need to adjust backlash by adding or removing shims under said bearing, wouldn't that change my preload? I'm trying to work in the smartest way possible and slowly so I don't do things backwards. Thanks a lot!
Before you set your preload on the pinion, you must first set the depth to obtain the correct mesh with the ring gear. Unless you have the set-up tools (which I don't have!), it is trial and error best done with some set-up bearings that have been ground to drop on rather than press on.
After eveything has been fit, then its time for final assembly where you then set the preload, at least thats how I do it.
If you are just installing new bearings on gears that were already running together, most of the trial and error is complete as the original shims in the original order usually get you very close on the first try.
Thanks, Donny! Do you know the nominal depth of the pinion on a D25? I'll start there and shim up or down as needed. Mine has a +2 etched on it,but I would like to know where to start.
Get or make some setup bearings. They really help to get you close.
I can't help with the pinion depth or "+2". That +2 is used when you have the set-up tools that lay across the bearing saddles. Are you reusing your old gears? If so, pull the old bearing off the pinion shaft (gear end), and the shim stack under the bearing will get you close. If you have new gears, its a bunch of trial and error. I'm guessing you at least have a dial indicator?
Yes, I do have a dial indicator, Donny. And also yes, reusing the existing gears.
Reusing the existing gears do as suggested, put everything back the way it came out as far as the pinion bearing and shims under it. You may have to re-shim the front bearing to get the correct preload for the new setup. Once you have pinion back in and the preload set, then you can put the ring gear in and set backlash. Dana axles are a pain in the sense they don't use a crush sleeve making it a little more fit and test to get preload correct, and side shims are behind the carrier bearings so have to pull bearings to change shim setup. I'm brave enough that I would just replace bearings and put everything else shim wise back like it came apart. The universal pinion depth checker is a useful tool as well as a "how to rebuild" differential book. The best money you can spend is on a pinion and side gear bearing puller. But it will set you back $200. If you are only doing one gear set the tools are expensive, but by the time you've done 4 money well spent! In addition, a hydraulic press is handy as well, but bearings can be driven on with a hammer the way mechanics did 50 years ago.
OTC tools make a nice carrier bearing puller, part number 4520.
Its the one on the left in this picture.
Here it is in action.
One of my carrier side bearings was on very tight and the puller "bit" the shims quite hard when I pulled it off...you will want to have some extra shims for this and other adjustment reasons.. Once the 44 year old bearing was off the new bearings went on and off several times and the puller never hurt the replacement shims.
This is what it did to the shims on the side with the tight bearing.
A press makes the bearing installation very controlled and easy.
I used the depth gauge procedure to get the pinion to the checking distance as a starting point.
These measuring tools are what I used.
Be aware that used gears will not give you the "ideal textbook pattern" when you check with the gear marking compound.
Thanks a lot, Oz! I have a bearing extractor that works fine, yours look better though! I also have all those tools. My original question is: What should I be looking for when it comes to initial pinion depth? Do I need to attain a certain number? And also, MikeC suggested to do the preload first and then work on the ring. Again, my original question is: Once I have the preload and backlash, if I need to correct the pattern by shimming under the inner bearing, doesn't that modifies the preload value? Still confused about what to do first. I don't mind the hard work, I just hate to fumble around without a certain path just to realize later that I need to go back and do it reverse. Thanks for helping!
I personally do not know the checking distance for the D 25 but the reference in this link suggest that it is 2.250" with the 5.38:1 gear set Willys Jeep Axles on CJ3B.info
There are 4 adjustments that we are concerned with, they are pinion depth, backlash, pinion bearing preload and carrier bearing preload.
The following is not detailed instructions but rather just a quick summary of how I do a Dana axle.
I set the pinion depth with calculated quantity of shims under the inner bearing cup and then install the pinion with the inner and outer bearings, oil control washer & yoke and tighten the pinion nut down very snug but still able to rotate without great effort, I am not concerned withe the pinion preload shims at this point but I also want to avoid tightening it down too far that it damages the bearings.
I then continue with the carrier side bearing adjustments and when I am satisfied with the backlash and carrier bearing preload I then paint the ring gear and check the pattern. If it looks good I adjust the pinion preload with the shims under the outer bearing to achieve the correct inch- pound rotational torque with the pinion tightened down to spec.
I then recheck the backlash and if is still within spec I will clean and repaint the ring gear and check the pattern again. After interpreting the pattern I either finish up or disassemble and repeat the process until I am satisfied.
I have done the setup before with only a couple of attempts to get it right and I have done one that had taken me 11 attempts to get it right.
The more times the carrier goes in and out without using a case spreader the greater the risk of damaging the axle surfaces where the carrier bearing cups drag on when installing and removing the assembly.
I recently made a yoke holding wrench and it makes tightening down the pinion torque easier so now I am more inclined to set the pinion preload right away after setting the depth. If I have to change the pinion depth after paint checking the pattern it's not so hard to do so with the yoke tool.
(Edited to add picture)
Awesome, Oz! Thanks. That is an awesome summary that answers all the questions I have so far. I will take a jab at it this long weekend. I'm trying to use the front axle as a rehearsal for the most important one: the rear.
A few suggestions...
Paint the ring gear and get a pattern on the current setup, take a picture for later reference.
As the others have mentioned...keep track of the shim pack that comes out of the current setup and write down each and every time you make shim adjustments. Its easy to get confused and lose track of what you have tried.
Without using setup bearings and/or a case spreader your shim stack on the side bearings will likely include the preload shims too, add a little grease to the sides of the machined area in the housing to aid the bearing cups to slide in easier.
Consider drilling and tapping a drain in the axle housing if one is not already there.
A dial type torque wrench is ideal for determining the pinion bearing preload but it can be done with a length of lath board and a fish scale.
12 inch pounds = 1 foot pound, install the lath with measured reference points & holes for the scale and swing it at a controlled right angle in a circle to record the rotational torque.
Use only gear oil to lubricate the bearings, do not grease them.
Thanks! Those are awesome ideas, and that tool is great! I borrowed a dial torque wrench, but that invention is a keeper! Thanks again for your guidance and time. This is, as I have said before, the best jeep foum ever!
Does anyone know the nominal pinion depth checking distance for a Front axle D27A 3.73 (1966 CJ5 V6)?
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