Gears & Axles - The 12 bolt information thread

I've been doing a bit of reading and of course a lot of 'Searching' yet the info seems rather scattered and inconsistant.

So how about using this thread to correlate information about the 12 bolt rears.

And before people start saying why bother, I'll tell you. There are some people out there that may well break a stock 10 bolt but a 9" is just to heavy duty for their needs, hence the 12 bolt fits the bill.

What I think would be useful here is to post facts NOT heresay. On topics such as the differences between the different manufactures and what benefits each one has, in terms of build, fitment, sepcification, supply, price, ease of installation and so on.

THIS IS NOT A WHICH ONE IS BETTER, JUST HIGHLIGHT WHAT IS DIFFERENT AND WHAT WOULD BE NEEDED EXTRA WITH EITHER SETUP.

In addition if the only thing you have to contribute is either negative, non-constructive, or even just plain stupid please don't bother to post it at all.

If any are curious why I started this thread, it is that I have spent many hours trawling thru threads to find only slating matches and very little info. Also as I live in the UK there are very few (if any) Fbody specialist who I can ask.

Thanks for your help, and lets try and make this a good resource for everyone.

This would be great... as would a 9" thread. Also something along the lines of descriptions to different options... posi, spool, locker, soft locker, etc.

Ive already figured out what I want to purchase from doing the same as you.. handfull of searches and a couple hours worth of reading.

well...my father and i are in the process of installing a moser rear in my car, it looks like a "stout" piece so far, but here are my gripes thus far.
1) not only do the torque arm bolt holes not go all the way through, but they use A SMALLER BOLT...what gives w/ that, AT LEAST the same size...makes no sense, my father is goin to put in a helicoil i think...i believe the moser size is 1/2"-13 instead of stock which was 14mm...u would think they would put bigger bolts than 14 mm, a heavy duty rearend should have bigger bolts not smaller ones!
2) the brake line bracket from body to rearend deosnt bolt on...there is a tab on the stock bracket that wont allow a straight forward bolt on process...
3) the rearend doesnt have the stock dimensions!!!...my stock swaybar is now very close to hitting the adjustable knobs on my hal shocks!! everything is closer inside...
4) why not have a nice weld on sway bar brackets?...they say use muffler clamps...my car is show car and race car..so i bought a sway bar bracket set from bmr(i have a gripe about that but ill spare all of you haha)...plus wouldnt a muffler clamp twist a little bit?...my bmr weld on pieces wont budge a bit when my father welds them in..
5) why cant there be little tack welded pieces on top of the rear end so u can hold the brake lines...the last thing i want on my car is some stupid ugly looking ricerish tie wraps!...

i think thats it...haha.. :bang: ..but seriously, all those little things can really piss a man off after a while, i bought it used for a very good deal about a year ago and am just getting to installing it now, but for the money one pays for a rearend, you would think the stupid company could do all those little things...thank God my dad has very good machining skills and works at a shop that he has acess to a whole ton of machines...

After install a Strange Engineering 12 Bolt, here are some notes:

1. The Torque Arm Mount Holes go all way the through, just like stock.
2. The axle tubes are stock diameter and no need for bigger sway bar clamps.
3. It comes fully assembled and is shipped with oil.
4. Plan on 6-8 weeks for delivery.
5. Their tech line rocks and used it several times.
6. The oil need changed at 1000 miles and every 2 years therafter.
7. The grease fittings on the axle tubes need greased every 5 years.
8. The recommened oil weight is 85W-140 and hold 2 quarts.
9. Still need 1 bottle of GM Additive.
10. The brake line tabs are welded in the stock location and has the sway bar location tabs as well.
11. The 3 Channel ABS Sensor has ~28 gauge wire and I used some plumbing fittings to help secure it.
12. Did not need to shortene my driveshaft.

just make sure strange puts seals in ur rear ,they forgot mine and it blew after 80 miles and out i pulled her and sent her back for warrenty repair so far no trouble yet but i've only driven a couple of times to work.oil every where on backing plates rotors and pads

are you sure of the additive amount and oil weight i talked to jc from strange to make sure since he sent me a rear with no seals the first time,and he told me 2 additves and 75 w oil ???

After install a Strange Engineering 12 Bolt, here are some notes:

1. The Torque Arm Mount Holes go all way the through, just like stock.
2. The axle tubes are stock diameter and no need for bigger sway bar clamps.
3. It comes fully assembled and is shipped with oil.
4. Plan on 6-8 weeks for delivery.
5. Their tech line rocks and used it several times.
6. The oil need changed at 1000 miles and every 2 years therafter.
7. The grease fittings on the axle tubes need greased every 5 years.
8. The recommened oil weight is 85W-140 and hold 2 quarts.
9. Still need 1 bottle of GM Additive.
10. The brake line tabs are welded in the stock location and has the sway bar location tabs as well.
11. The 3 Channel ABS Sensor has ~28 gauge wire and I used some plumbing fittings to help secure it.
12. Did not need to shortene my driveshaft.


was there any negatives at all?

are you sure of the additive amount and oil weight i talked to jc from strange to make sure since he sent me a rear with no seals the first time,and he told me 2 additves and 75 w oil ???

You would have to use 80W-90 at the minimum, if you have the Eaton Differential. The 75W-90 is synthetic and not compatable with the Eaton Differential. The GM LSD Additive is still required and states this on the break-in procedure. I guess 2 bottles would never hurt. I emailed Strange about the scheduled maintenance and they recommended 85W-140.

was there any negatives at all?

They only two negatives I have was :

1. The wait time is lengthy, especially if you have a broken 10 bolt rearend.
2. The 3 Channel ABS Sensor could be designed better with thicker wires.

Overall, Strange was a better choice since it was fully assembled and tested. Also, I have used their customer service line a few times and they are extremely helpful and willing to help you. One of my pet peeves is the after the sale service.

They only two negatives I have was :

1. The wait time is lengthy, especially if you have a broken 10 bolt rearend.
2. The 3 Channel ABS Sensor could be designed better with thicker wires.

Overall, Strange was a better choice since it was fully assembled and tested. Also, I have used their customer service line a few times and they are extremely helpful and willing to help you. One of my pet peeves is the after the sale service.
does the abs sensor wires protrude from it so you would have to cut the connector off the factory harness and splice the wires or do you just plug in the stock connector?

You have to cut the cable from the factory ABS Sensor and splice it into the Strange ABS Sensor. The threads on top of the Strange ABS Sensor is 3/8" NPT. I went to The Home Depot and bought a 3/8" NPT 90* elbow and a 3/8" NPT coupler. This way, there will be no stress on the thin wires coming out of the top of the sensor. I ended up soldering the wires together and covering with electrical tape. Cover that with flex loom and secured the cable to the brake line. So far, so good.

Where is a good place to get the strange Rear end?

im getting mine directly from strange, but there on a 1 month back order so im waiting for this winter

I bought mine from Tom Byrne when they were having the double online discounts and saved $200.

Well after researching, I went with the Moser.
1. Received unit in 5 business days, Strange told me tubes we're backordered and would be 6 to 8 weeks.
2. Was told was stronger, and after looking at the posts here, seems the tubes are larger.
Install was easy, I kept as close to factory as possible so the unit came without the axles installed, needed to put on my brake backing plate then press on the bearing (or you can have this done at any machine shop). Drilled a small hole in the housing to mount the rubber brake line. Tie wraps on lines at the ends. And a conversion U-joint from 1310 to 1350.
Noise is tolerable, lot quieter than my broken 10 bolt. I can hear my stereo again :)