advice on a sure grip

[70Tom]

So, I'm starting to do some research on adding a sure grip to my 70 Sport Fury. I wanted to get some suggestions on what I should do.

Car currently has 8 3/4 open with 2.76 gears in it.

1) Should I buy one already built/put together in a case? I believe I need a 489 case, no?; OR

2) Should I just purchase a sure grip carrier and have someone rebuild what I have?

Adding to this, I think I'd like to switch out to some 3.23 gears to get a better combo of power at the start and still semi-decent highway mileage.

One issue of buying on currently assembled is the quality of work (i.e. did they do a good job). On the other hand, I'm not entirely certain what I'd need to have someone build one out. I'd probably be looking at more money (I've seen a built out sure grip, 489 case, 3.23 gears for $800 locally).

In any event, I'd be interested in suggestions, what I need to do to my current drive train to switch, etc.

Thanks in advance.

 

[thrashingcows]

I would highly recommend the 3.23's....much better over all gear then the 2.76. I have run both in my wagon and love the 3.23's.

Couple things you have to remember is that the 3.23 ring and pinion is no longer available new....so used is your only source. I had a spare set a few years ago but sold them while I was having a brain fart. The complete pumkin assembly for $800 does not seem to be an unreasonable price to me, if it's a fresh rebuild. I rebuilt my own cone sure grip unit, and then had my diff guy install it in my 3.23 housing, with all new bearing etc. I was close to $500 out the door for that.

 

[70bigblockdodge]

If your changing gears and sure grip I would just get another center. If you just wanted a sure grip with same gears I would just swap that into yours.

 

[moper]

Find a local 4wd truck place and have them swap the gears and/or install the limited slip. Axle work has some specialization in terms of tools and techniques so if you don;t have some talent and cash for the right tools it's cheaper to pay a professional. 4WD shops do a TON of grea changes. I'm not a fan of used stuff unless you know the guy and have seen the car. Too much worn out crap on the market now. I do not advise buying the "rebuilt" cone type differential, and have seen brand new cone types fail in very short order in heavy cars. If you are looking to upgrade, the Tru Trac is a great street option that you'll never break or need to rebuild, however it will also require the Green axle bearings.

 

[thrashingcows]

Why would the Tru Trac require the use of the inferior green axle bearings?

 

[moper]

The diff uses a fixed center pin and adjustable tapered bearings don't work with them. "Inferior".. that's some funny stuff there...lol. They do just fine on a 4K lbs E body going around a road course at 160mph. They've been in service in that car for 10 years now with hundreds of laps at Watkins Glen and thousands of mile on the Long Idland Expressway and local roads. Nevermind millions of GM products on the road and being raced. Tapered can hold more pressure, for sure, but they are overkill for most applications & need to be cleaned and greased regularly. In this case, the better diff can't use them and the Greens will perform just fine.

 

[polara71]

Guys swear by them ....Guys hate them... I've heard enough to stay away from green.

 

[polara71]

3: 23 3:23 3:23 ..... The best all around gear in our 3 speed automatic equipped cars....

 

[BIGBARNEYCARS]

Anything you're driving over 3500-3800lbs, why bother with a sure grip? You're never going to have ah Competitive Street Brawler no matter what you build. As mentioned above, the 323 iz the best all around road gear. Unless you're running ah 489 or some such nonsense and you're object iz to pull stumps and get paid for it, I'd stick with what you've got. Just my humble opinion, Jer

 

[polara71]

Because there's something weak in the mind with a peg legger

 

[65sporty]

Yukon gear makes 3.23 gear sets
YG C8.89-323: High performance Yukon Ring & Pinion gear set for Chrysler 8.75" with 89 housing in a 3.23 ratio

 

[70bigblockdodge]

When did GM use ball bearings?
Even modern R&R bolt in hubs use ball, straight roller, ball. Everyone knows those never fail.
I thought true trac was offering it without the pin so you can spacer the center like a spool or butt the axles they do not need the pin (no spider gears) it is there for all the hundreds of c clip rears that it fits.

 

[twostick]

Dr. Diff has 3.23 gears for the 742 and 489 case. The 489 gear has 29 splines. If your 489 case has a 10 spline yoke you will have to replace the yoke.

Get the crush sleeve eliminator kit while you're at it.

Cass is the go to guy for all of your brake and drivetrain needs.

Mopar 8 3/4" (8.75) Ring and Pinion for 741, 742, or 489 case

Kevin

 

[67-Fury]

Grow a pair & Run a Spool. Don't worry, You will regret it.

 

[Mr C]

Anything you're driving over 3500-3800lbs, why bother with a sure grip? You're never going to have ah Competitive Street Brawler no matter what you build. As mentioned above, the 323 iz the best all around road gear. Unless you're running ah 489 or some such nonsense and you're object iz to pull stumps and get paid for it, I'd stick with what you've got. Just my humble opinion, Jer

Totally agree. Back in the day in Canada where I'm from, many cars were radio delete and roll up windows, but owners made damn sure it had a heater with Sure Grip for winter driveability in snow. For a restored classic getting use at cruise nights on sunny days, it's a BIG waste of $$$$ and only an ego feeder to be able to say "I have a Posi" (yes, I know it's sure-grip...I did that on purpose.).

 

[MEV]

Just go with a detroit, its barely noticable on the street and bullet proof. It would have been way cheaper if I would have started with a detroit. I broke an eaton torsen style diff with my 3:23's in my Newyorker. The Detroit made a huge difference in traction. That and cal-tracs and drag radials finally got my car to hook.

My newyorker has the green bearings and runs 12.80's on drag radials.

 

[moper]

"Guys swear by them ....Guys hate them... I've heard enough to stay away from green."

Many enthusiasts have no idea about cause and effect and why something failed. Fixing the "effect" does nothing to stop the "cause. I agree with the Dr. Diff referral. I buy all my gears and differentials from him. He is great people. Read this link: http://www.doctordiff.com/blog/tech-info/why-green-bearings/

My Newport was a competitive street brawler...lol. It wasn't a 12.0 car but it would more than hold it's own against most stuff we ran accross. 4dr, 383, single plate nitrous, 3.55 Sure grip. Good enough to break the entire housing for the sprag off the transmission case...lol. My 69 300 is going to be a lot quicker and faster. The fact they don't look fast helps in the wagering.