# Rear end



## kenbaustin (Dec 24, 2010)

I have 10 bolt rear end on my 1970 Pontiac Lemans and think its time to replace it. I was looking to upgrade it with a rebuilt one or something reasonable priced. Siphon Performance has a strange Dana 60 that runs about $2300 that's with new drive shaft that is required bc length dif etc. Also not sure if my right stuff conversion brake kit will work with this either? Any advice on other less expensive options? Thanks.


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## BearGFR (Aug 25, 2008)

Hey Ken,
The Dana 60 is strong enough to stand up to King Kong, and it's also heavy. The first question I have is how much power are you carrying and how do you enjoy the car? If you don't race it much (or any), haven't done things to it to make it "hook" (suspension, sticky tires, etc), and haven't upped your engine power significatly over stock, then you'd probably be way ahead in the long run to just have your existing 10-bolt freshened up. You could even replace the internals with something like an Eaton posi unit and take a jump up in strength, still for a lot less money than replacing the whole unit. That's also for sure keep you from having to mess with your brakes.

Bear


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## geeteeohguy (Feb 2, 2008)

What Bear said. You can buy a complete rear end in good condition, drum to drum, for anywhere between $100 and $1500, depending on gear ratio and if it's a positraction unit or not. A good 3.23 Safe-T-Trac (posi) should be less than $900 ready to go. A less desirable but more practical 2.56-2.78-2.93 open rear end will cost under $300. I've been running 10 bolt rear ends in my GTO's for decades and they've held up very well behind tripower 4 speed abuse. Save your $$$ for other things.


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## kenbaustin (Dec 24, 2010)

Thanks for the responses. Just using the car as a driver not racing. 400 engine about 300 HP. Any idea why I would keep going through rear wheel bearings? I replaced mine a year ago and they have gone bad again on me with less than 1000 miles. Seal leaking on my right rear and have about 1/2 inch play side to side in the axle at the wheel also replaced the spider gears last year bc thought they might be causing the play in the gears also had the axles checked out and they were within spec. Just tired of messing with it do you think if I do rebuild get new axles etc it would resolve my problems?


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## PontiacJim (Dec 29, 2012)

For your HP application, the factory 10-bolt should be perfect and give you good service. Here is a great article on the 10-bolt, 12-bolt rears from GM used in their cars. Great tips in identifying your rear & axles, plus upgrades. Auto Classifieds - Hemmings Classifieds feature cars for sale nation wide | Hemmings Motor News In the search engine, type in B-O-P Rear Axles and this should get you right to the article.

If you are having problems with just the one bearing, then I suspect it is not the entire rear end, but just that axle side. Confirm you have the correct axle and not a donor axle from another brand. Does it match the other side? Next, is it straight? Have it checked for straightness. From what I have read, 1970 used the smaller bearing. I prefer Timken brand bearings over others and if you get an aftermarket (inexpensive Chinese) bearing, the dimensions could be off just enough to create a problem. I am thinking that the bearings should be sealed and they get pressed on the axle. Been a while since I did this. If so, then the bearing should not be the problem. Make sure you are getting the correct seal for your axle tube. You might be getting the smaller bearing seal? Test it in the end of the axle tube before you have it installed with the bearing on your axle shaft. Test fit the bearing as well.

Next thing to check if all looks good so far. There should be a small vent somewhere on the axle or housing. If this small hole gets stopped up, it does not allow your housing to "breath" as it gets hot and cool. As it heats up, it builds pressure. Too much pressure just like a tea kettle, and its got to go somewhere. Can blow out the seal. And of course, don't over fill your fluid or this too will create seal problems. 

This is just how I would try to isolate the problem by checking parts and pieces to make sure each item is not the problem. Eventually you should narrow it down. Worst case scenario, you spring for another axle, put all new bearings & seals on it again, and go from there. If still a problem, then it may be the axle housing itself either damaged or bent on that tube giving you the problem. So give the axle housing a good look over as well, make sure your control arms are good and not allowing the axle to *&%[email protected]^!*&%[email protected]^!*&%[email protected]^!*&%[email protected]^! at an angle causing more strain/flex on one side/bearing/seal than the other when you apply torque to that right wheel.

Keep us posted.


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## jetstang (Nov 5, 2008)

Sounds like the axle is bent, causing pressure on the bearing, had a buddy going through the same thing right now, found welds in the axle tubes, outside repair looked fine.


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## geeteeohguy (Feb 2, 2008)

My experience, on a bunch of GTO's over the years with the stock 8.2 10 bolt: top of the line sealed Timken bearings (hard to find) are mandatory for good service, and the bearing must be a strong press fit on the axle. A LOT of these axles spun the inner race at one time or another, and they are undersized where the bearing gets pressed on. This will result in bearing and axle failure. Good bearings, and a good axle. These bearings go for 100-200,000+ miles typically before failure.


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## kenbaustin (Dec 24, 2010)

I'm thinking about putting a 9 inch ford rear end in my 1970 lemans. My 10 8.2 rear end needs alot of work and I dont know if I want to keep putting more money into it. I plan on keeping this car so and dont want to have to mess with the rear end again. Is the 9 inch ford rear end which I can get for about $1500 and will work with my existing brakes sounds like a good way to go? The GM 10/12 bolt units that I'm looking at are more expensive. Thoughts?


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## ALKYGTO (Mar 29, 2010)

What are your long term plans for the car? Stock, pro touring, drag? 

Honestly the stock rear will hold up to some abuse from a 300-400 rwhp automatic car for a long time if it is in good shape. I would listen to these guys who suggest a good used 10 bolt Pontiac rear with a mild gear for a "stockish" car. 

If you plan on big power later you might be on the right track with an upgrade to a 9 inch, 12 bolt, or "the Ultimate".....The Dana 60.


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## kenbaustin (Dec 24, 2010)

Its a driver and I'm looking mainly at price and reliability. I have replaced the bearings and seals on my 10 bolt twice in the last year and they keep on leaking, tried National and Timken bearing and seals. Its in the shop now and the differential/carrier needs to be replaced, may need new axles as well. Waiting on the final quote but guessing its will be $1000+.


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## BearGFR (Aug 25, 2008)

We're all talking in general terms of course, Ken, but your specific situation might be different. Everything said has been accurate, but if you have an opportunity to get a 9inch at a good price, it's already set up with the right mounts to fit your car, it's in good shape, and you want an axle you can forget about no matter how much abuse you heap on it - then it's hard to argue against that choice. I'm running a Moser 9inch in my car (I like to think I "need" it) and I love it.
You probably could have your current one made "right" for the same or less money, but you'd have to find someone capable of doing the work right without ripping you off. Any deal you're happy with is a good one.

Bear


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## allpawl66 (May 9, 2008)

kenbaustin said:


> I have 10 bolt rear end on my 1970 Pontiac Lemans and think its time to replace it. I was looking to upgrade it with a rebuilt one or something reasonable priced. Siphon Performance has a strange Dana 60 that runs about $2300 that's with new drive shaft that is required bc length dif etc. Also not sure if my right stuff conversion brake kit will work with this either? Any advice on other less expensive options? Thanks.


Have the same S-60 in my 64 with 424 hp. 484 torque @ the rear wheels , put it in and you will them have the ability to upgrade more HP in the future . S-60 is bullet proof .


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