The tool for measuring pinion depth is fairly simple, but you can often get away without it. I use a piñon bearing, honed out for a slip fit, to select shims and then double check with a new bearing, pressed on the pinion gear. The shims for Dana rears have shims that are made to go behind the pinion bearing race. You can choose the proper diameter of these, in place of the shims that go on the pinion gear. The concept for setting backlash and side bearing preload is also fairly simple. Have one adjuster all the way nearly out, no contact with the side bearing and tighten the other side adjuster to seat that side bearing. Then back out the tight one and tighten the other side adjuster to seat that side bearing. Then tighten the ring gear side adjuster for zero backlash, with the non-ring gear side adjuster backed out or just barely touching, no pre-load. At this point you don't want pre-load on the bearings, but ring gear side has to be tight enough to eliminate backlash, just tight enough for that. At this point, the ring gear side adjuster is done. Then tighten the non-ring gear side adjuster for proper backlash. This will pre-load the side bearings and spread the case slightly. Lacking a dial travel indicator, this adjustment is about two spanner wrench holes of tightening on the non-ring gear side adjuster, after contact with the seated bearing. To recap, the ring gear side adjuster is set to zero backlash with the gears and no pre-load and no tightening after zero backlash is a achieved. Then the non-ring gear side adjuster is tighten to set the gear backlash. This will also pre-load the side bearings. The non-ring gear side adjuster pushes the ring gear away from the pinion gear, while pressing against both side bearing, for their pre-load.

Most of this stuff is way over my head mechanically, but I still find it interesting to see how this is all done. Also the reason why I respect anyone that can do this kind of thing.

Never expected to learn this much about diffs. Plus, that's way more tools than the average guy like me will likely ever own (I'm jealous). Good video

My '71 came with a 741 carrier with 2.76 gears; I was going to use either a 489 or 742 with 3.23 gears (got both used but in great shape. ) But since I'm putting in an OD transmission I may find happier gears to use and would have to rebuild one of them so its great to have this video lined up.

Good video! I had 3 489 center sections 323 highway 456 st 1/4 513 1/8 mile for my 67 Cuda mild 70 340 11/1 4spd, solid lifter, ported J heads, Holley 780 4150, sub frame con, adj pinion snubber, SS prings. Some how I cracked the caps on the 456 gear center section after words I made cap straps. Really enjoy your videos as myself or family owned most of the cars you show including the Studebaker except the 300's.

My brother and I changed a cone posi on his 70 Dart Swinger 340 back around 1973. He was 19 and I was 21. It was quite easy. Ran great and no noises. Never took the pinion gear out as it wasn't leaking. No bearings either. Just the carrier. Probably about a two hour job including taking the tires on and off. Rebuilt a 273 in 24 hrs too. Rings and bearings. That included yanking the engine in and out and starting it. Had to get the cherry picker back in 24 hrs! Mopars are easy to rebuild and repair.

Thanks Jamie lm fascinated by work i could watch it all day

I used the service manual to set carrier bearing preload and it howled like crazy. I’m Leary about doing another one. Nice job.

I had so many questions about rebuilding my 489 to put taller gears in. You answered so many of them and confirmed a few of my suspicions! Thank you, you rock!

I learned how to rebuild several of the cone clutch type Sure-Grips. I'd have a machinist friend cut 0.100" off the outer side of each cone clutch, then make up several spacers (looked like a doughnut when finished being made) from random pieces of sheet metal in thicknesses like .020" or .030", then reassemble with a combination of spacers until I got it right, minimal gear lash, for full tooth engagement. They worked great after that. All the ones I did were in 489 cases.

This was great information! Keep doing what you’re doing brother, it’s very appreciated

Thank you for sharing your knowledge 🙏 Jamie

Once again, very well, executed and detailed video Jaime

Great video on the 8 3/4. Thank you!!

I was missing your videos. Showed up right on time 😃

Awesome video, so glad that it's not just me having issues with interpreting the paint patterns.

I was always told to find someone who knew about them and avoid a lot of troubles, did learn a bunch from this video, thanks for sharing your knowledge!

I love your videos, but I enjoy these tech videos the most. It's how I found your channel long ago. I'm trying to do more and more things by myself at home instead of paying someone else to do it. That being said, I am still scared of all that is required to set up an 8 3/4, including the tools I'd need to purchase to complete the task. I don't have a press. Right now I'd still rather keep multiple 3rd members on hand with different ratios to swap in and out when I want a gear change. BUT... I did learn what those " buttons" (9:51) are that fell out during my last swap.

In my opinion 323 is a good ratio for daily driving . Had this ratio in most of my 🇦🇺Chargers. Valiants owned 2 / 68 383 pillares Dodge phoenix With that diff that always looks bigger then a 9 inch 👍🏻had 2 / 66 Dodge phoenix with a similar diff both poly 318 but man did they pull strong 💪 . The ground would shake under those boys and would leave two black long lines no worries man those motors sounded like they came of a NASCAR track not sure what my old boss did with them but they were MOPAR heaven . Great clip 👍🏻🇦🇺.

Thank you and good content....

I hang the transmissions at my job at the truck plant. Part of said job is measuring the backlash on those transmissions that have a PTO to install. Pretty similar to what you did. All in all, that didn't look too bad, with some "special" tools. Nice work.

Great Video !

Very informative thanks

I have always used blue grease to check final gear lash. Never cared for the yellow paint they came up with in later years. Note though 489 cases are super strong so but so is the 742. The differnce is the pinion shaft thickness. The 489 has a fatter shaft thus why it takes more abuse. However i have yet to break a 742 pinion yet. Saying yet so i dont jinks myself. If you have a auto 742 works great. If you have a stick and love burnouts 489 is what i was told. I have beat both into the ground. However the only one i ruined was a 489 case go figure. Now if your pinion goes back into the ring gear the word carnage comes to mind. There will be loud noises you can clearly hear and feel from the drivers seat. You may poop your shorts too. But most times you will blow a u joint over a pinion. Only talented guys get to distory a chunk. 😂

Good info. Thanks!

I love sandblasting. It's so satisfying 😊

Awesome vid. Now I'll be able to rebuild the 8 3/4 in my 300. Now I will wait for you to do a full 440 rebuild :)

AWESOME....MOPAR 4 EVER.

Nothing I'd rather do on a rainy Saturday than look at rear ends.

Perfect timing

Next video from DDG: Rebuilding and upgrading your A727 or A904. Appreciate the knowledge that you have bestowed, hope to tear into the Diff on my forward look car.

Thx Jamie

I wish this had come out a week sooner! Just had to do my drop-in and was trying to figure out reusing the crush sleeve on the 489. Turns out "yeah its no big deal" when using the original R&P. To be fair, you can reuse whatever crush sleeve was with the diff and alter the preload with the shims in the pack.

Another fabulous how to video. The only thing that could have been better is the camera work. You really need a camera man or uhh.. person? I love to see all the intricate details of a procedure. I need to change my gears. I have a 489 housing. And allegedly I have a fairly new Yukon unit in it. I want to go from 3.73 to something more highway friendly. I might attempt it this summer. But I would much rather pay someone else to do it that has all the proper tools. Anyway keep up the good work!

Now I await the day you get into the dreaded Chrysler Dana 44 front axle 😅 Been needing to find a hub seal kit for it

Mmmm, 90w. Good vid!

It's nice seeing someone do it correctly, unlike me who would use the impact and just wing it till it feels good to me 😂

Jaime looking for an eight and three-quarter for my 75D 100 I heard that some 8 3/4 will fit like out of a bodies for a wider tire in the rear. Another great video. Thanks.

It's a shame all rear axles aren't a drop out style. So much easier than setting pinion preload under the car and set backlash under the car with shims. One trick I did setting pinion preload/torque on my 9" was to use the press to hold the pinion flange secure to the press plate and torqued it. It didn't move a bit and I used a couple pieces of 4x4 to protect the ring gear and used the press to press the ring gear onto the carrier and it also held it securely to tighten the ring gear bolts. Way easier than when I did the 8.8 in my grand marquis, that was a PITA under the car.

Great instruction! Have you any experience with Eaton limited slip, the gear style?

I watch some KZfaq mechanics, this channel separates pros from amateurs...good work, im not sure if it's my Mopar Bias showing but your making the Jr mechanics look bad chief 😂😂. Cheers

I need to swap out the center in my 72 Challenger because it still has a spool in it from it's past life as a drag car. I found complete new centers on ebay using Yukon cases with Eaton Tru Track helical limited slips for approx $1400. I was just going to swap the centers and then sell my spooled 323 center. Have you had or has anyone here had any experience with those helical LSD's? Are they ok for the street or should I just go with a clutch type? Also does anyone know, are those Yukon nodular iron centers as good as factory? Thanks in advance and as always, awesome video!

Swapping a LSD from another 8.75 (one of those old late 50s you mentioned) should go the same right? My open 3.23 is a 489 from a D100, other than the crush sleeve making the install different, the LSDs are swappable between housings are they not? I’ve done the 9.25 and 44 in my Ramcharger but not a 8.75 yet.

Woot!!

I got two 80s model Fifth Avenues with a 318 they look nice but kinda slow of course 😂. should i get one of these and if I did would it fit or should I just rebuild and upgrade the diff that's in one of them already?

Worked at a Jeep dealership some years back. They were having a lot of bearing failures. Never enjoyed rebuilding the rears.

Do you know if the prebuilt third members that mancini racing sells are any good ? I can't see me doing all of that and not screwing it up.

Pretty okay timing

Do you have a break in procedure for new gears and sure-grip?

That Petty blue Charger speaks to me.

I was pumping gear oil out of my differential in my 72 Barracuda, and the plastic stem fell in, l just looked at ur video to see what I'm dealing with and it looks like it's going to have to stay. My question is do u think this is going to effect the differential being left in there. Thank You

Question. I have a rear end that I switched from an open rear end to a sure grip. Both are 741 cases. I removed the button from the sure grip carrier as I replaced the axle bearings from Timken to Green bearings. The axles, both sides, will not seat into the axle housing. I used the correct bearings. What might be my problem? I don't want to beat the axles in & I have tried turning & pushing at the same time. Any suggestions?

What bearings are on the new power lock number

Had race from my demon diff explode while removing, dug 2 pieces out of thumb,1 remains.😮

I’m sorry for stating in the video wen your axcel took a crap that it was cause of the case you had which went I thought about it it would have nothing to do with the centre section or you would of had a hole in it is it the crush sleeve that makes the 489 betteri got a 742 with 488 I might use it for the small block in the car till I put the 440 6 but that won’t be built till winter in a 72 dart swinger but we will see

Well that's way more complicated than I ever knew.

Jamie I got a question for you now I thought the 489 was better than the 742 I watched a video yesterday day stating that the 742 was the best. Over the 489 and the smallest the 741 all I can say is you must have some torque in that little motor in the demon I only say little meaning a small block to twist that axcel the way you did

You weren’t specific about the side bearing preload. This is determined by total turning torque of the assembled unit. Great video tho. I built countless diffs in Jeeps. They were setting them up too tight from the factory and bearings were failing like crazy. Good times…..

the #2 diff. is stronger, the pinion bearings are wider with greater load capacity.

Lmho great job

As I get older.... I desire taller gears. True.

So my 73 8 3/4 has cone?

👍🏻🇦🇺

It’s just missing the front pinion support like in the 9 inch ford for ultimate strength

You reuse old bearings that you grind inside the race.. get them correct with shims reassemble with new bearings.

Use a punch to remove the ring gear, through the ring gear bolt holes. Easy peasy.

Indifferent 😮😊tyall 😂.

I've learned that I never want my rear end to fail 🤣 And if it does, this video will get a lot of views as I try to fix it. I'm a slow learner....

I have a 69 Dodge charger, with a 408 stroker. It has a rear Gear ratio In the twos, What would be a good year combination that would be fun on the street and drink a shit ton of gas

If this is the big MOPAR, what happened to the Dana?

Get some one to hold the camera!

I watched this once again Anyone watching this dont ever just skip the last step because this guy is either to lazy or to ignorant to get right.. Notice how he explained all steps in detail minus the one he doesnt know how to get correct and is the most important guage of your overall gear setup.. So his wear pattern is way way off.. your pinion and ring gear should leave a pattern right on the center of your ring gear like a half circle. Shouldnt be to low or to high dead center of each tooth on both sides.. He doesnt even explain what your measuring or how to correct it. You can either spin the gears with your drill while with gloves on holding some pressure against ring gear hence creating a load! If this isnt correct, the difference is astronomical to longevity of the diffs life.. There are a million diagrams online that explain how to correct it wherever your wear pattern is. No one ever gets it perfect first try.. I do this professionally. So the reason his is off is because his pinion depth is off. Was most likely off from factory with same shim the 1 right behind the pinion teeth. Behind the bearing. As long as preload and backlash are to spec then its the shim for his depth. And you can adjust those carrier adjusters in and put all day long but wont get it correct until his pinion is at correct depth.

booo put a dana 80 under it

Diffs... ugh!

3rd member rebuild vid. Channel "pillar" or "filler"? You're channeling someone's 9th grade shop teacher here, sir. Not funny. Too informative!