A fellow I know, broke/shattered his 8 3/4 differential yoke launching a 3400 lb. Dart on a transbrake, that has a 520+ something cubic inch wedge engine and a 727 Specialist's 727. He absolutely refuses to inspect the transmission internals for sprag damage. He has no shield or blanket. Should I just leave him to it and wait for the " I told you so moment "?

 

Just your his friend and he should do some research himself... And tell him a big loud... "I'm Warning You!! Hear me now and thank me later"
That's all you can do... Oh and Don't drive it yourself.... But I think you got that one...

Or just Tell him Bob said your an idiot... Or Bob said you have too have it inspected. !!!!!!!!!!!!!!

I sure if he calls Keith he will get told to send it in, unless it already has a Bullet proof Sprag built in it.

 

Bob

I don't think there is an unbreakable Sprag. I have gone through several 16 roller "Super Sprags" while getting my car to launch with some consistency. I am lucky as my 727/904 Protrans is all 7075 aluminum internals which are good to about two - three times the failure rpm of the steel stuff. And I run a CSR Carbon Fiber shield!

Below is a quote from ATI on " Class Racer.com " - which rearend would I be better off with, which makes note of their 1000lb. sprag failures.

http://classracer.com/classforum/sho...t=57286&page=2

post #11


We are changing the Challenger over to a Dana right now. I need to run a 5.13 at our weight and the 8 3/4 would ratio would break in less than 10 passes. But a 4.88 would last 100 passes usually. We are 3470 lbs. And yes it sucks to break a gear with a 904 and then worry about the sprag - even with the big sprag we made for them it was 50/50 weather or not it was junked. - Also of note is that I will have 4, nice 8 3/4 pumpkins to sell! 2 Alum and 2 steel.


I have tried my best to get this friend to do the RIGHT thing! Or at least to telephone 727 Specialist for advice!

 

That would be the point to drive home... "The sprag is the weak link" Ultimate 6 bolt is about as good as it gets.... But you are rite if you wing them! you better check them !! Bottom line.. You can sure roll them over doing the burn out in first and it bits the track to hard. Your in trouble..
Protrans is nothing to worry about.Good Guys and good stuff... For me there about a 1-1/2 drive one way.. I have had a few Front pump problems with there stuff and a few broken servo pistons and those rolled over sprags. But thats just Mopars..

I think Most shields are Hard to fit!! unless you open the tunnels up...lol
CSR is good stuff... But I have not tried to kill one..lol

The Dana 60 is a good deal... Or the 9"... Good parts for both available..
Wow...You really need the 5.13 gear set????????
The Motor is going to be singing a good tune up in the RPM band !!
I know My Roadster Did, and it had a 32" tire on it. And we left @ 5000RPM

Not sure why it was breaking gear's.. Sounds like to much Housing/member Flex?. Sounds like the car likes to leave a bit softer RPM wise? We had some bad luck with ProGear for awhile. But we found out they had a bad run on production...
With the Dana you can use the Strange gear set... Pricey but well worth it.

Ok... I feel like I'm rambling....lol

 

You've told him about it, remind him again in a few days and leave it at that. Some people need to learn the hard way.