NEW 2 Piece 3rd Member
 

Here's a few photos of the new rear end design I came up with at the Tulsa Pontiac Nationals.

The pinion still turns freely and the spool is still mounted solid in the bolted in part of the 3rd member and all of that turns freely as well. The only noticable damage is there are some teeth shaved off of the ring and the ends of a few teeth on the pinion are bunged up.

This all happened on the 1-2 shift at about the 60' mark.

i have a carrier if you need one. probably be a fortune to ship.

Ouch! OEM member? Might be a good time for an upgrade to something like a Strange Pro Iron member.

that should buff right out...

Man !!..looks like a 9" trick..:(
What generation(year) case it it ??
Does it have "the extra" rib/brace ?
Just curious...

You going back with same...??

This is just the old Olds/Pontiac rear end, Dil just did all the new bracing and locator to this last year...just making toooooo much power for stock parts!!!

Ouch!!! Too much HP. Looks like It's time for a Good Mark Williams third member. Nice Launch Photo!!!

Isn't it better/easier to take the bolts out if you want the 3rd member out?

:D

Man that stinks.. Dewco makes some good stuff, they have good people skills too.

60 mark, bet that made a mess! Won't have to worry about anything rusting back there for a while! At least it was after the exhaust! I don't see the 'N' stamping anywhere, guess it's time to upgrade!

.

little welding, it oughta clean up good

dang, big power, be careful what you wish for

It is a Nodular piece, or should I say 2 pieces. We are evaluating the carnage as Bill puts it to see if we can determine the actual cause, or point of failure. This rear set up had about 20 passes and like I said, both the spool and the pinion in the broken part spin freely.

I don't believe there was any flex in the housing and that's all braced up extra heavy duty.

I've been leaving on the foot brake so everything is preloaded. I have only used the trans brake 1 time and that was at last years Pontiac Nats. That's what took out the rear yoke. We're wondering if that may have fractured the gears.

We're looking into the possibility of a broken ring gear tooth getting wedged in the pinion and pushing the setup apart breaking the housing away. It's a clean break and cannot see any twisting action.

BVR, I'm with ya on that one. I think a lot of people get all worked up with big dyno numbers, big engines, and big horsepower. I know I did. The challenge is planting the power to the pavement and keeping everything together.

Dil,
how heavy is the car and what were your 60' times??
i have this type of rearend in my car and now you got me thinking twice.

The car is 2995 and I'm 215. 60' 1.22 leaving the line at 2,000 rpm on the foot brake.

The pinion support and webbing on the 57-64 case is really good. I would say at least equal to a regular Ford 9". You can buy billet caps, 35 spline spools, forged yokes, brace the housing, but you can only get street gears. And they can't take the punishment like the softer pro gears.

Poncho, what rpm are you launching and what have you done to your rear end ?

Bill and I were talking and wondering if I may have fractured something last year when the pinion snapped. I probably have only made a dozen or so passes since that happened.

This tune is making just over 1,000 lb ft of torque and the torque is lower at the 6500 rpm shift point than it is at launch.

We added more fuel and almost 3 more lbs of boost for the event ( still under 10lbs) and that could have pushed the capacity over the top too.

Does anyone want to buy a really nice, 35 3/4" heavy duty rear end less part of the center section. New Mark Williams 35 spline spool, New Moser 35 spline axles, 4 link brackets, shock mounts, Anti roll bar mounts, Wheelie bar mounts, Olds/Pontiac housing ends. Seems to have worked just fine at or under the 1,000 lbft mark in a 3,200lb beast.

I think you found your cause of the failure. You mentioned in a previous post about the possibility of it being a tooth that got knocked off the ring gear, wedging itself between the ring and pinion, causing the pinion and housing to "break away".

I had a similar failure in my 8.5" 10-bolt in the Discomobile. Had all the bells and whistles in it like you have in your rear to make it live...but like yours the weak point was the street gears. After a couple dozen passes on nitrous, it let go, similar to yours (on the 1-2 upshift), busting the heel off of every tooth on the ring gear, and busting off a couple of ring gear teeth completely...but the housing and everything else lived. I was able to limp it back to the pits and even drive it onto the trailer, until it hit the one spot with no ring gear teeth (LOL).

Time to upgrade to a rear that you can find Pro gears for...you're making too much power for those brittle street gears.

Bill and I have been going over and over discussing all of the possibilities and have agreed that the initial cause had to be gear failure.

I'm contacting Richmond tomorrow to see if they will cut a set of gears out of the pro material.

Brian, something that Bill and I were thinking,,,, they ran these rear ends back in the day in blown nitro cars. How the heck did they live ? May be a question for Steve Barcak.

I don't think those blown nitro engines in the rails were making that much power back in the early days...those 392's I'm guessing were making around 1000-HP. Clutch and tire technology wasn't what it is today either...initially they slipped the tires instead of the clutch. Big difference between that and your car hookin' and bookin'. From what I have seen in the funny cars by the late 60's, when clutch and tire technology was better, most cars were running a Dana-60 rear. I'm sure they still had their share of failures prior to that though.

This may sound sacrilegious, how about putting a 9" center section in your current housing? If there is an offset differance or spline differance of course your current axles wouldn't work

Just a little FYI
 

Just a little FYI.................I've been running STREET gears in my 74 GTO 2,900-3,000 lbs. W/driver) since I've owned the car (Dana 60 W/3.73 gears). Last year was the first time that they broke. With this engine the last 2 years I've made over 50 pass's with a trans brake leaving at 3,400 RPM's - 4,400 RPM's, the gears were 15 years old (Dana/Spicer gears). 1.15 quickest 60" times at over 1,000 HP. Maybe it's the BIG Dana! :)


GTO George

Hey Bill, what shop is this article refering to? I already have a 40 spline 9" that I was thinking about installing in the funnycar...need to narrow and change the brackets, this would be easier to do with the rear in the funny now. This would work great for Dil since he has already set up the case for his GTO. Thanks, Bill also