I have a 3.27 posi 9 bolt in good condition. it does not need overhall or repair. im going to pull the axles so I can switch the caliper mounting plates. im converting iron calipers for pbr. I see ill need a slide hammer, but I will not need to press the axles back in because im only changing the caliper plates correct?
when I reinstall the axles, will they slide right back in or do I need any special tools? thanks

 

A slide hammer is your best method, however, I have always been able to get the axles out by simply tapping the back of the axle flanges with a med hammer. Tap and work your way around and they should come out. To reinstall, I usually just tap them back in with the hammer, sometimes with a block of wood if they are stiff. Be carefull when you have axles out not to work or cause the differential spider gears to move. Inside the posi the clutch flange and spider gear both have to be almost perfectly alligned to allow the axle splines to fully engage. 99% of the time this won't be a problem just make sure you don't turn the axle with the drive shaft locked down. Since the axles are in place now the splines are alligned. It should all go back together smoothly. However, if upon reinstallation the axle goes in to the splines about 1/2" and stops, that may be the reason.

 

the axle flange slides over the axle and the bearing and locking ring press onto the axle, so the only time pressing is required is when changing axle bearings or seals

 

I agree.

Few things I learned by taking mine apart:

You probably want to put some PB Blaster or similar on your retaining bolts prior to the work. They like to corrode and stick because they collect moisture.

A very light dab of anti-seize on the inside and outside mounting surface of the brake rotors help too. That way they don't bond to the rim or the axle flange the next time you take it apart.

Don't be surprised by few quarter sizes spots of differential oil loss. It likes to collect on the bottom tubes and you will get a very little bit as you pull out the axles.

If you do get the splines out of alignment it's more work but you just need to get the rearend positioned where you can turn it over slowly by hand (transmission in neutral or with the driveshaft out) to get the carrier and posi cone splines to realign again. As you do it with any luck the axle will pop right back in. It's sounds easier than it is. Took me 5-10 minutes messing with it last time.

Also if you have any nasty looking wheel studs or wanted to use some ARP longer ones now would be the time to have new ones installed.

 

I have a question about my 9 bolt. I have a 89 Iroc the axel is the borg warner and has the aluminum calipers. i have been trying to figure out if i have a posi or not. I was able to clean off the tag on the diff cover and it says i have the 2.77 ratio but i cant see the code stamped into the axel tube. did that axel for that year come come only with the posi or was it an option. everything i have been able to look up so far says that it does have a posi. thanks

 

I think all 9 bolt GM rearends are posi units.

 

From what i have been reading it can go either way

 

Dave,

How about Lucas oil?

https://www.lucasoil.com/products/di...0%20Gear%20Oil

Says no additive needed.

Also I'm looking it into a Tur-Trac from Harrop

http://www.harrop.com.au/drive_detai...99-TTRC9837-00

Any re-seller in the US?

 

Don't know about the Lucas oils but I used a Pennzoil product that was supposedly for limited slip differentials and the diff creaked and popped until I put the GM additive in. There was such a pronounced difference after adding the GM stuff it was amazing. I had actually thought I had put something together wrong it made so much noise. I had shimmed to "0" play so it was tiiight. The GM additive is all I use now. I don't have the part number but it should be listed earlier in this thread. Prior to shimming it would turn both tires in a straight line but when turning right only the inside would spin. After about a year or two of pleasure driving and a couple of trips to the drag strip it will still turn the car sideways during a right hand turn (off road- closed course driving lol) and paint 2 equal length stripes on the road so it is holding up well.

 

I ran additive in mine originally and have recently been running synthetic 85 140 without additive with no chatter. Granted my rear has some miles on the clutches, but still has enough meat to burn posi for as long as I want it to

 

I use synthetic as well, but still add the GM additive.....

 

Jack up the rear and spin the tires, if they spin the same way you have a limited slip differential.
If they spin opposite each other, it is an open differential (non posi)

 

Just a quick check, an M80 LSD won't fit in a M78, but a M75 will fit in a M78?

 

M78 for camaro firebird and ( valiant and ford and nissan owners) (M75 M76 to you morgan sports car owners)

BTR Borgwarner axle news


New trutrac style centre for Series 3 9 bolts

https://www.facebook.com/SupaFSeriesSpares

https://www.facebook.com/SupaFSeries...type=1&theater


http://supafseriesspares.com.au/prod...sd-torquelock/

email and ask for one for a 28 spline M78 axle

will take 3.73 3.89(91) and 4.11:1 gears no probs direct fit

you have to machine the slightly-domed face of the pinion head for other ratios (common across many brands) diff head is big, hits carrier before you get good pattern, the lower the number of your ratio.

works with any australian gear set 2.92:1 up but machine pinion head

works with any greaset bigger than 3.08:1 if you stay with US GM supplied Camaro/firebird gears

check the centre that comes out these only replace series 3

sereis 2 the centre is held toghther with bolts that sit 1-2mm above the ring gear flange
series 3 centres and those bolt heads sit on a pedestal 6-8 mm tall

the series 3 centre has the ring gear flange in the normal place
the series 2 has it offset to the left by 8 mm when you look from the back of the car

these trutrac style centres are series 3 style centers

even at $600 thats 1/2 the price of the harrop tru trac and less tha n half the price of the KAAZ 2 way clucth plate centre 3820

I call that a bargain, hence have one on order.

PS Moser engineering will also make you some new half shafts if you want....
strange engineering didn't like the small half shaft bearing and suggested i get mopar housing ends welded on... didn't wanna do that so went with moser.

as usual too long but nothing a cut-off blade can't fix

bye

Dave

 

M80 gears fit M80 posi and neither will fit an M78 housing


M75 gears fit M75 and M78 posi as the posi is identical
M76 gears fit m75 and m78 posi becasue the posi is identical

M78 gears fit m78 housing with standard bearing set from RATECH

M75 gears will probably need different head and tail bearings to fit into an m78 housing but they work. people have done it its not a problem

M75 is a 7.5 inch ring gear beam axle, with a slightly smaller housing but the same posi as an M78. you can get an M78 gearset in but you have to grind the housing entrance.

M78 is a 7.8 or 7 3/4 inch ring gear and a slightly bigger housing

M76 is the rule breaker its an M75 ring gear in either an M76 IRS housing or an M75 ring gear in an M78 beam axle housing. still got a 7.5 inch ring gear mind.

the M80 is a big IRS housing with a bigger M80 centre and it fits in a familiy of hydratrac centres that includes an M86 and an M90 (think dodge viper sized)

the only seperated cone based slip resistant beam axle called M86 they made was a limited run for the last of the VJ Valiant chargers (was designed to go behind a mopar 340) rare as Hens tooth paste hard to rebuild and sort after by about 40 australians with specifcally optioned VJ valiant chargers. it looked like an AMC 20 from the rear big heavy thing gets called a dana but isn't and never was. you won't see one in the states ever.

so if you see the term M86 its usually inrleation to a modern IRS

they also made M55s and M60s for teeny tiny cars in the 60s but nobody knows anything about them and a doubt they were LSD.

confusing isn't it


so for your Camaro or firebird rear end

series 2 carrieir you want M78 gears Marked 0578 on the ring gear and in 2.77:1 or 3.08:1 (sourced only from US 9 bolt)

series 3 you want m78 gears marked 0578

and australian sourced 2.92:1 3.08:1 3.23:1 3.45:1 3.73:1 3.89:3.91:1 4.11:1 etc

you don't want 2.77:1 from Oz unless you have a series 2

gears with 0575 marked are m75 they will work fine just you have narrower tooth space on ring gear and pinion set up might be akward


keep in mind old australian gearsets in 2.77:1 2.92:1 and 3.5:1 used smaller bolts to hold on the ring gear. so the holes in ya flang might be a bit big

get it drilled again exactly between the orginal bolt holes and life is good
or jusrt risk it. the gear is held on by friction between it and the flanged caused by the bolts being tight like a wheel is. they are not in shear stress.

the thread is in the ring gear not the flange


Dave

 

So this will fit in my 9bolt which has a 3-series carrier and the original 3.27 gears with no modifications? Or do I have to machine anything if I have the stock 3.27 gears?

I am seriously tempted since i replaced my cones woth new ones from 9bolt.com this spring and shimmed to 0 play, worked flawlessly for about 2 weeks now acts as an open again... I have new cones at home and was thinking about doing it all over again next spring...

It would be awesome if i could just put in a torsen and never have to touch or think about the rear end again

 

It will fit your 9 bolt

the ring gear will bolt right on in the correct place in releation to the pinion head when the carrier is dropped into the housing (obvioulsy needs appropriate preload and pattern set up)
however becasue your gear set is 3.27:1 the pinion head is of a size that will drag on the fat middle of the centre Note how the centre doesn't neck down like the orginal

so you would put your pinion in a lathe and remove a few thou from the top of its head after you have recorded any setting depth info stamped on it.

i'd re write or restamp that info so it can't be lost

these work best with 3:7:1 upwards where the pinion head is smaller , then you don't have to machine the pinion head face.

you have to do this work with many of the aftermarket centres a competant diff shop will be used to haveing to do this.

best bet is to stay up late or get up early and call suprF spares and have a chat

you have a Borgwaner/BTR M78 axle with 28 spline half shafts (much like every v8 car produced by anyone of the big 3 in australia from 1970 does)

with that info John can assist. they are in work at 8 am

i live in the UK i.e far enough away to cause time difference to be a pain so i just called em up one night when i stayed up past 23:00 (08:00 in melbourne australia)

if you put "what time is it now in Melbourne australia" into google it will tell you

then 0061 (03) 9305 2522 drop the zero before the 3 i.e used one of the cheap calling numbers in the UK "ratebuster" and got 1Pence per minute international dial

he'll probably be slightly bemused at this sudden interest from abroad, in a product he has been selling for years... but thats just a case of him not having told anyone about his product i guess. they specialise in US Ford F series truck parts...so he can definitely speak American

Dave

 

follow-on question:

if I'm not changing the gear ratio, I'm reinstalling the same factory original gears, keeping the same pinion depth shims, could I just touch the head of the pinion with a grinder to get the needed clearance between the pinion gear and the fatter diff? I know, not as elegant as taking it to a machine shop.

 

Depends totally on your pinion even for the same ratio they are all different. Hence the different checking distances stamped on them. Touch with the grinder or a more involved job you won't know till you try. I was told my 3.45:1 set would be on the boarder line for having to do this, but my 3.89:1 ratio would be fine

its all beacsue the torsen style centre needs to be or at least appears to be easier to build if its barrel shaped

if you want one that doesn't need any of this done you can pay double and get this UK made version for BTR beam axle

http://shop.quaife.co.uk/differentia...55&sub_type=16

in the middle

Morgan sports cars use a M76 axle from Borgwarner BTR its an M75 ring gear on an M78 Posi in an M78 beam axle housing
so its just the camaro 9 bolt with a ring gear that has a 0.3 inch smaller outside dimeter

your 0578 ring gear will fit

check the blue print here

http://shop.quaife.co.uk/media/blfa_files/QDH3M.PDF



Dave

 

Well, that is going to be the most stupid question ever, but I'd like to be sure: is this topic 9-Bolt Rearends (295hp rated) the one that comes with the 1989 GTA?

This is mine:


It has 150k miles, and seems to be ok, expect for a slightest oil leak at the end of the right axle end. Mechanic says it's ok.

Should then I be worried about doing donuts/burnouts?

thanks

 

Yes, your 89 GTA got the 9 Bolt Borg-Warner Australian built rear axle.

 

Only way to know if it's good would be to pop the cover and check the cone clearances and planetary assembly.

 

Thank you guys

Well, if I open it, I would have to change oil too, and what if I discover something wrong? Here in Italy could be a problem. I prefer to wait till something bad happens.

Thanks!!

 

How to check your posi unit in car:

Secure car safely with wheel chocks etc, remove handbrake and place gearbox into NEUTRAL with the vehicle off. Raise one rear wheel from the ground . Measure the torque required to rotate the wheel that is off the ground. This is called the breakaway torque, and if less than around 35lb/ft the centre requires attention -- either shimming or cone replacement.
NOTE: A very quick test can be done without the use of a torque measuring apparatus by hand by attempting to rotate the raised tyre by hand. As a rough guide an average person should have a reasonable amount of difficulty rotating the raised wheel, if able to do it at all.

 

I can now confirm that the Helical Gear LSD that dave999 mentioned, indeed fits the 9-bolt. I just finished the install in my car tonight! See my full install post in "Transmissions and Drivetrain"!

A very special thanks to you "dave999" for telling us about this!

 

what are the differential cover bolt size? i broke two not knowing the previous owner put red loctite in and i need some replacement bolts

 

No problem


glad its all worked out


dave

 

So is the differential/posi you are installing a 28 spline? Do you know if there is a 31 spline available? I am considering a conversion to 9", 12 bolt or possibly the ford 8.8. But my 9 bolt if working fine and the main concern is the axels (from what I read on 9 bolt site) and I know I have a twist in one of mine. I noticed there are 31 spline cones for the stock posi and if I am getting axels made it may as well be 31 spline units. If in the future I needed a posi I could possibly go this route if the 31 was available. I know that everyone says the small ring gear is still a problem but others have said the stock 9 bolt with good axels is better than their reputation.

I put over 400 HP to the rear tires on motor and over 500 HP with nitrous. With a stick shift transmission I would really like to be able to leave harder but have yet to really try with the stock 9 bolt. I don't mind pushing the limit but want to be safe doing so.

 

The diff i bought was a 28-spline, I reused my stock axles and just installed new seals and bearings on them. My axles looked great, no twists and the splines looked like new, no wear at all. My engine is completely stock though, and I don't know how everything would hold up to more power.

 

If you want 31 spline axles, rebuild the posi with 31 spline side gears and cones and you are good to go. Pull it out, keep shims in same place, don't disturb the ring gear. open carrier up swap side gears and cones, check shimming and put it all back as it was. if you want 31 spline axles Moser engineering did me a set of 28 splines axles for my Australian valiant so they know the bearing sizes and housing end sizes. My measurements are here http://www.moparmarketforum.com/foru...72&hilit=Moser but keep in mind my car has a wider 9 bolt than yours and mine is a Mopar. but I do expect the press on bearings and seal surface dimensions to be the same. 31 spline side gears cones and heavy duty spring packs can be had from G andJ differentials http://www.gjdiffs.com.au/multilingual-ready/ here is their Ebay shop http://stores.ebay.com.au/Street-and...=p4634.c0.m322 you will get no products listed unless you use ebay.com.au or you could try 9 bolt.com its probably the same equipment from the same manufacturer but Mr 9Bolt is at least local US based. I used Australian suppliers for my diff internals and US supplier for my axle half shafts because I live in the UK. if I could have got the stuff from my local dana dealer I would have, but dana corp doesn't seem to know Australia and south African factories made these diffs under the spicer axle brand. The left hand doesn't know what the right hand is doing in that multi-national company. Dave

 

so I bought the carrier bearings and axle bearings and seals did they change the design of set 9? axle bearings they look like they will fit but they are not the normal cone bearing that I pulled out .
the new ones are 1 piece with a lock ring retainer but they do come with the separate retainer ring im just wondering how to install it as it looks like the bearing would need pressed on to axle shaft and then would then need also need pressed into the housing but im thinking if pressed into the housing it would damage the seal ?

the old style bearing can separate to allow the axles to be pulled out the new bearing would break or be damaged doing the same ?

 

my recollection is that the different brands had differing configurations for the bearings and bearing races. i had bought several different brands, scraping the bottom of the RockAuto barrel, but in the end, only used the Timken bearings.

as i recall, the bearing race should slide out of the axle housing, it's not a press-fit. if it's attached to the bearings themselves, then it should come out with them. if it's the original style like the Timkens, then you can pull it out with your fingers.

i think the slide hammer is used to pull the seal out, and also to break any form-fit that may have occurred between the axle splines and the spider gears.

just my recollection from having done this task a few years back.

 

I literally did this today, pressed the bearings on my axles. What I found was that when the set came out of the bag, it looks like one whole unit. I think there is really sticky grease in there. I also thought something was wrong since the old bearing was separated, the cone was not locked on the retainer (there is a name for this piece, not the bearing retainer, but that thin piece above the cup/cone) so I put it in the parts washer to get the grease out. After cleaning and spinning the bearing for a long time the whole thing finally came apart. I read the Timken instruction and it is normal for the whole thing to look as a unit and you are not supposed to clean the grease out

 

Did this on the left side (again...) about two weeks ago since the (not even one year old National Seal brand) axle seal started leaking suddenly. Turns out the seal I put in when I restored my rear had a manufacturing defect.

Since I had to replace the bearing again as well because you have to destroy it in the press when you take it off, I can tell you that the inner and outer race seems to be _glued_ together on new bearings (At least National Bearings brand) for easier installation.

 

Keykey, how do you like the Torsen?

I checked with Supa F Series about one and they are $545 aud for the unit plus $240 to $300 shipping to Kentucky. Kinda pricey.

 

Oh crap, I emailed them too, but I nevere got to finding out about the shipping. I ran out of cash on my other cars

 

I love it, I'm so glad that I don't have to deal with the stock cone diff anymore, and the oil still looks like new since I put it in as there are no more metal flakes from the cones floating around .

It's still working great and I consider it the best upgrade to the car so far!

I just ordered two Bilstein shocks and new springs for the rear, so we will see if the Torsen is still my number one upgrade after the Bilsteins are installed

 

Anyone happen to know the outside diameter of the 9 bolt axle tubes? Are the the same size as a 10 bolt?

 

9bolt.com has this available and the shipping is less but the cost is more so it probably works out about the same. Glenn is probably the expert on this rear end. Currently working with him on a 31 spline carrier and gears. It's hard to justify spending the $$ on this rear but should be a good deal in the end if it holds up.

 

Did you find this info? The 9 bolt is bigger than a 10 bolt. Look for the axle bearings for each rear and it should give the outer diameter for each bearing

 

I'd love to give this a try. Be a great Christmas gift to myself. :-)

 

Thanks man. I'm doing a 8.8 swap and needed the axel tubes but they have to be he same size as 10 bolt tubes. So I need to get a 10 bolt now.

 

I have not measured the outside diameter of a 9 vs 10 bolt but the sway bar brackets appear to be the same for both so I suspect the outside diameter of the tubes is the same. Don't just go by the bearings. The 9 bolt uses a totally different type of bearing and axle retention than the 10 bolt. If I were welding stock tubes to a 8.8 ford rear chunk I would probably use the 9 bolt tubes since they have the bolt in axles which don't require c clips. Once the housing is together I would have custom axles made with outer bearing/flanges of a 9 bolt and length/splines to match the 8.8.

If you have a 9 bolt housing available I may be interested. I am looking to build up a 9 bolt and just need a good housing.

 

That's a good point about the bearings. I have a car with a 10 bolt and 1 with a 9 bolt. If I get time this evening I'll put a caliper on each so we'll know for sure

 

Let me know if u get those measurements. Any as for selling you the 9 bolt I'm not against it but the shipping might be crazy from Ohio to get it to you.

 

Checked the axle tubes.
10 bolt - 2.64
9 bolt - 2.63

 

I had emailed Moser about axles for an 8.8 center with 9 bolt axle tubes about 3 months ago. Their reply was $370. FYI

 

The guy that I'm going to have do my 8.8 is TNT fabrication he said that the custom axels from his supplier won't work on the 9 bolt so I need to look into it a little deeper to see if I can have him put the 9 bolt tubes on the 8.8 but maybe use those moser axels or I'm going to use a 10 bolt and use c clip eliminators

 

Any chance of getting a list of years and models (were any offered in the Camaros of any model? If so what years?) put into the first post in the thread?

 

9 Bolts came on 86-89 FBodies. You can get all parts and more info from 9bolt.com.