Spitting Driveshafts

-
1

12many

Well-Known Member
Joined
Dec 14, 2016
Messages
3,571
Reaction score
4,690
Location
SC
I finally broke something!! :eek: after 4 years of slowly working down the 60’, ET and up on the MPH.
Best to date is 11.44@114 with a 10” TA 3500 tight. Best 60’ was a wheels just getting up 1.60. Not content, I finally got around to swapping in a 9-1/2” FTI 4000 hard hit for just a little bit more oomph and first run today with a lame burnout still netted a dead hooking 60’ of 1.54.
Back out for a second run, excellent burnout and it was a “hard hit” alright! Wheels up bigger than ever and “Bang”!! Pooped out the driveshaft. Seems I’ve exceeded the durability of certain factory parts. :eek: Couldn’t help but think of his great tune:



Time to upgrade and re-enforce.

B0C5B2A4-0584-432A-A2CC-38B54785F0CF.jpeg


ACDCBE14-020B-4C64-B672-02185DC48C22.jpeg


6B26F77D-8DEA-4178-9DC1-F125B8D169A1.jpeg


5A4C6E55-0291-4ED5-AABA-0EA7F1D41B65.jpeg


474D303E-015B-4A33-8909-3033B53C9C1E.jpeg
 
Last edited:
You need a yoke that has the u bolts that run all the way through and have nuts on the back. Those are the really heavy duty ones. Like a.......dare I say it.....Ford 9". lol
 
....and congrats on the 1.54 and big wheels up!
 
Chances are very good that the trans (sprag) is hurt since it broke under load.

Several years ago I was at a double-header points race. Stripped the ring & pinion on a T&T run the day before. Because of points, I took a chance & swapped in a new center section and won the next day. Unfortunately, the trans went out at the next points race at a different track. Luckily, it was another T&T run so I was able to withdraw again for that event and not be penalized in the points series.
 
12many said:
I have to remove the drive shaft to tow on a dolly and every time I’ve messed with those straps I’ve said I gotta swap to u-bolts and yokes. Well I get what I deserved for procrastination but I think I dodged a bullet with the trans (over-running clutch)
Click to expand...
Have you thought of towing backwards from the front?
 
12many said:
I have to remove the drive shaft to tow on a dolly and every time I’ve messed with those straps I’ve said I gotta swap to u-bolts and yokes. Well I get what I deserved for procrastination but I think I dodged a bullet with the trans (over-running clutch)
Click to expand...
Man, I hope you didn't hurt the transmission. That would suck. It's such a great combo. A brick that hauls ***. I love that thing.
 
Once you get that threshold raised, you'll then have a lower one. I know this is somethin you may not wanna hear, but have you thought of a Ford 9"?
 
IMO, a steel billet yoke using Spicer solid u-joints are the way to go, whether it be an 8 3/4", Dana 60 or anything else. The ring & pinion then the carrier caps are the next weak links on an 8 3/4". OEM driveshaft is in the mix, but you likely need another one anyway so an aftermarket version will help there. I got a Dana 60 for my car which had around 1.50 60' times and a 1.47 best @ 3,540+ lbs. But I never got around to installing it before IHRA dropped my class.

Weight is a big factor and I'm guessing you're in a truck? (Ok, I see it's a van!)
 
12many said:
Honestly, I’m already running times that most tracks will require a roll bar. My problem is it’s just not the vehicle for that, I mean, it’s a death trap roll bar or not. I’d need a cocoon type cage, like a shark cage. There is a member here who just posted about his freeze plug blowing on his Dart, and into the wall he went. If I did that ^^^^ in my van I know I’d be in a world of hurt no matter if a had a roll bar or not. Would not be pretty. A poster mentioned “threshold” .....I may need another vehicle to cross that. I might be slow walking a reality check here.
Click to expand...
That might be smart thinkin. Just accept the van for what it is and keep havin fun. I know it puts a big grin on your face.
 
I use u-bolt style with GM style joint. Its tose 1/4 28 bolts and straps that are the weak link. You can use the same drive shaft if its straight just get or make a cross over joint.
 
C46F9811-59EE-4584-8FFC-3D355894A1A9.png
The 1350 and the 7290 (large mopar) joints are almost identical in size. 1350 has the clips on the outside and 7290 on the inside of the cup. You should really pull the trans and check the sprag. Oh, stole the picture off Dr.Diffs website
 
I think I might have bought 2 or 3 and still have one new in pkg . I will check ....
 
Rear sway bar will help with the twist. How long is the front spring section on it?
 
I will no longer complain about my shock angles or any of my rear suspension issues ever again! 1.5’s with that craziness! Thats working.
 
I thought about using the shortest adjustable shock you can find and fab up a bracket to take the place of the snubber. You would probably have to offset it to one side of the center section to get enough length. You could then tailor/smooth out the hit.
 
Raised the front spring eye up? Huh, its seems to be working and there is no arguing with success. It must separate a ton! With the spring on top of the axle. A rear sway bar would really help.
 
furrystump said:
I thought about using the shortest adjustable shock you can find and fab up a bracket to take the place of the snubber. You would probably have to offset it to one side of the center section to get enough length. You could then tailor/smooth out the hit.
Click to expand...
check out the lift arm on a dirt late model!!
 
Don't sweat those straps, they are junk.
I hear you on wanting to avoid the wall, the design of the van, with your feet close to the front bumper is scary, I had a 69 van years ago.

The one drive shaft I blew out, never figured out what happened, it went bang, and ran over the drive-shaft.
All the straps intact, u-joints still good, output shaft / with gears still bolted to chucked drive shaft, end of pinion still bolted to rear yoke.
77 jeep CJ-7 340 NP 435/203 Dana 44 rear, changed the transfer case, fixed the rear, un-bolted the broke parts off the chucked rear, drive shaft and it was running the next day.
No more power shifting on the street with 36" tires.
 
You must log in or register to reply here.
-

Back
Top