Need instruction changing out differential/rear end 69 RR

[frank]

I have a 69 RR 4 speed; I’m in the process of changing out the differential/rear from a 3.91 to a 3.23. Never took on a project like this so any help would be appreciated. I’m in no rush so time is not an issue my concern is to do it right the first time.
One step at a time would be helpful

Thanks, Frank from Delaware

 

[Red63440]

Are you changing out the center section as a unit or are you having the gears changed in your existing unit? Either way you will need a drain pan, a new gasket and the correct gear lube on hand. You wil also need jack stands and a roll around floor jack.

 

[frank]

Changing out rear

Red63440

I'll be changing out the pumpkin as a hole no gear change.
OK
--Drain out the lube, into a drain pan
--New gasket
--Correct gear lube
--Jack stands.

Got it.

I'm sure there's a lot more................?
TH's

 

[MoparMitch]

Frank, You will have to remove rear tires and brake drums, then unbolt the axel flange bolts. Slide the axels out about 8 in to allow 3rd member diff. to be removed.

 

[godfatherofchry]

OK frank,let do a step by step..first put the jack under rear at the pumpkin jack it up as high as possible.put jack stands under each side in front of the springs.pull the wheels and tires off.then the brake drums they should slide off.then look at the Axel flange and you will see A hole big enough to put a 9/16th socket threw take those nuts off and Axel should slid out.you mite have to tap with a hammer.then get your drain pan with your 9/16th socket take all the nuts off except the top one just loosen it for now.pick up on front of rear until the oil stops sometimes the rear will stay there by its self.and after the oils dun draining move pan of oil out of the way.put your jack under the pumpkin take the top nut off and wiggle it on to the jack. then revers to put back in.....so you need a two ton floor jack two good jack stands.a 9/16th socket (deep)a 3inch.extension 3/8 ratchet drain pan and I would get sum oil dri or kitty letter......hope this helps..........O and I would get new oil 80/90 or better.......Artie

 

[ply64post]

Diff swap

Frank

Here is some info that can be helpful.My Mopar has a tire chart and speed gear info.Lots of info.Your speedo gear will need changed also.
Side bar My Mopar tools and references.

Jeff



http://www.mymopar.com/index.php?pid=22

http://www.moparts.org/Tech/Archive/axle/12.html

 

[oldbee]

Frank
Also, you might need to adjust axle end-play when going back together, if you have o.e. axle bearings. I can dig out the procedure if you need it. Jeff

 

[FridayGt]

Frank, I'll be gone this weekend and have no idea what I'm doing, but let me know if you need mindless manual labor after work or something. As long as I'm not down at Tony's parts trying to score an engine, I'll gladly help!

 

[blackblazer717]

Yes, end play may nd to be adjustes, unless a previous owner had green bearings pressed onto the shafts. Also, you must verify the spline count on the shafts so that you order the correct replacment chuck.
One note, are you sure you want to drop the radio that much? Whats your tire size? Reasons? Etc.

My 69RR has 3:91's with the close ratio 4spd. I have 235x70x14's, and she spibs at 2900 at 65mph. Personally i think the 391's are an awesome around town and occational highway gear

 

[frank]

717 responce from Frank




717, I’ll first address the question about way I’m changing out the 3.91 to a 3.23. I have no reason to run this car hard regardless of where I’m driving it (for the most part to and from shows). The car has seen most of the local shows; having said that there are some shows in southern NJ I would like to take the RR to but there too far for the 3.91 but easy for the 3.23 and will eliminate excess gas use. Having had this RR for almost 2 years my quest is to restore the car back to the fender tag, which is a 3.32 differential. I’ve changed out several parts that did not match the fender tag and still working on the list, with this being one of them. I also bought a bench w/head rest that will be installed, I’ll be pulling out 2 very nice 69 RR buckets w/head rest this winter.

I’ve never changed out a differential before that’s way I’ve been requesting input. I would like to get as much information as I can before I start the job.

Thanks, Frank from Delaware

Yes, end play may nd to be adjustes, unless a previous owner had green bearings pressed onto the shafts. Also, you must verify the spline count on the shafts so that you order the correct replacment chuck.
One note, are you sure you want to drop the radio that much? Whats your tire size? Reasons? Etc.

My 69RR has 3:91's with the close ratio 4spd. I have 235x70x14's, and she spibs at 2900 at 65mph. Personally i think the 391's are an awesome around town and occational highway gear

 

[5.7 hemi]

Dont forget to add the friction modifier. You can pick it up at the dealer or napa etc.

 

[frank]

friction modifier ?

friction modifier what is that?

 

[frank]

friction modifier .....nevr mind I found-out what it is.

 

[frank]

Parts for Review

Artie

The attached photo is parts I think you’re talking about, if so let me know. I do remember how to reinstall them, the lock and nut came off the passenger’s side not the drivers, is it suppose to be on the driver’s side?

I also included a photo of the gasket.........

Your thoughts.

 

[godfatherofchry]

yes frank that's it I couldn't remember which side because I use the green barrings to eliminate the adjuster.that looks like the factory foam gasket and you should be able to get at the places I told you. or maybe someone on here will have them....let me know how you make out and by the way that is a fine looking bird you have...........Artie

 

[Cranky]

Nice Beeper! It'll run fine with a 3.23. I even threw in a 2.94 into a 70 383 Challenger I had because I was on the road a lot with it. Mileage jumped from 12 to 16! What type of SureGrip does the 3.23 have? If it's a clutch type, make sure the thrust pin is still in it because if it's not, you'll never be able to set your wheel bearings. Cone type SG's never come out....

 

[frank]

Artie

Can't thank you enough for all the help; I'll try the 3 places you mentioned and see if they have the gasket.
Also, I'm about ready open and drain the differential (leaving the top bolt in) when should I unbolt the drive shaft? Is there a name for the gasket that I’m looking for?
Thanks

 

[frank]

Cranky

Thanks you for chiming in……..
As I’ve mentioned, I don’t run the RR hard and there is no reason to have a 3.91. The differential is a posi. And the RR has a 4 speed.

In reference to the thrust pin, I have no idea what to look for. Can you give me some idea where to look?

Thanks

 

[godfatherofchry]

Ok frank, my dumbness I for got to tell you about the drive shaft that should have been One of the first things to unbolt and get out of the way.any ways the pin cranky is talking about is in the rear the pumpkin.look in the holes were the axle goes and you should see a shiny pin the same size as the axle.if you can see threw the rear its not there.the chances of that is slim but it does happen good catch cranky. and you know if you have an old cereal box you could make your Owen gasket.or go to the auto parts place and get some gasket material.that's what I used to do before the green bearings and silicone..hang in there your getting it.......Artie

 

[frank]

Artie
I found the thrust pin and it’s in the differential so no issues there. I dropped the drive shaft (no problems) and took on the differential; for the most part is came out with some persuasion. Now it’s just taking off the old gasket and cleaning the things up. NAPA had the friction modifier so that will go in first I bought the best differential fluid they had and made sure it was 80/90, I’ll put that in next.
The only issue I may encounter is lifting the new differential into place, looks like the wife will be helping out.
Mancini had the axel flange gasket so I ordered 2 should have them by Tues. Other than that it’s getting things ready to be put back together.
Can thank you and everyone else for the great support during differential change out.
Thanks