Ever since I have been running a blower combo in this car, I have had no issues with the rear suspension. Until now. I was running hard this past weekend, and felt a bit of wobble in the rear in the shift from 2nd to 3rd. I let off and felt nothing. Not wanting to take a chance, I took the car back home with even slight acceleration making a horrendous noise in the back.

I checked everything, and found nothing. Just as I was putting it back together, I found that the right halfshaft would turn ~30°. Removed the halfshaft and found that the previously installed HD inboard U-joint was snapped. Both caps that install in the carrier were cracked (chunks missing) and the cross was broken. Thankfully, there was no damage to the underbody.

I have new Precision HD U joints ready to install, but was wondering what you guys are doing to make the rear live. I run hardened spindleshafts, fully built center chunk, and a cradle around the lower camber rods tying both sides together (this used to be my weak link). I have twisted/torn halfshafts in the past, but have been very lucky for many years.

Are you guys (Jeb, Art, etc.) hitting soft on the bottom end to save the rear, or are you running tires that don't hook hard enough to break stuff. In my other car, I always ran the 9" Ford, so it was not an issue. But this car with slicks (or my R1s, which is what I had on this weekend) now has me concerned.

I do not recall seeing issues posted such as these. Thoughts?

Thanks,
Aaron

 

I'm concerned too brother... What do you all think about Cryo? Jeb says he's never had a problem with his cryo'd unit even with dumping the clutch at an elevated RPM....Jeb, please chime in here....

 

I have billet spindles, polished posi, and its shimmed super azz tight. And to boot the whole thing from side to side is cryoed! All Im waiting on is the drive shafts to come back from Jeb. Im also running the spicer halfshaft ujoints, and the Neapco drive joints. I cant wait to side step at 5k with 440+rwhp N/A running 16X13.5 M+H slicks! I will let you guys know about my outcome!

 

MrCrowley,
Are you running the solid U-joints, or the channnel u-joints for lubrication purposes? My previous were solid, and they did not last for too many miles.

As for abuse, 4000RPM, slicks and lots of HP is the norm. But on this occasion, I really was not beating on it too hard and was running my R1s. They must have suffered damage prior.

Thanks,
Aaron

 

Im running the solid ujoints! Sounds like something was definately going wrong with them from the start.

Mike

 

Never fear, I am here...

Seriously... We've had one failure in one of our cryo-treated rears and that's Jim Barth's (TPI421Vette) and I believe there were other circumstances that caused it (namely the c-beam possibly causing the rear case to crack when he launched it- I'll get into that later). Anyway, I firmly believe that there are very few people as abusive as I am on the rears and I've yet to break mine (or my ZF). Now, with the new SB2 and the bottle I'm pretty sure it will be living on borrowed time with 1200+ hp and 1000 lb/ft of torque, but I'll cross that bridge when I come to it.

Do NOT use u-joints that have zerk fittings in them; the best is the Lakewood 1350's... I use them both on my '90 and on the '66 NHRA Super Stocker with no breakages, ever, period! If ya'll have any further questions let me know.
-Jeb

 

Jeb,
What about the U-joints with the zerk fittings in the caps? These have a channel that runs clear through the middle of the cross and allows grease to all four caps from one point of entry. Previously, I ran solid (no grease zerk) U-joints.

If not these, where can I get the Lakewood 1350s that you speak of? Approximate cost? I would like to get this back together, as I now have the (ver nice) Weldon fuel pump and filter waiting for abuse.

As a side note, are you sidestepping the clutch at 6K with these U-joints and the IRS? What sort of 60' times are you seeing?

I would compare your SB2 to the kind of combo in the '88 with the 18° heads and the D2R with a solid axle rearend. This will handle all of the abuse you can throw at it.

Aaron

 

I launch 5500-6000 by sidestepping... And yeah, that's on the IRS (not to mention that was BEFORE the spool). Never broke after the cryo; broke A LOT before then... The new auto I was originally thinking wouldn't be as violent, but with a transbrake and 6000 stall on the button it probably will be. I'll be ladder-barring the car next year and using one of Mark Williams new modular aluminum 12-bolt.

NO ZERK FITTINGS...ONLY SOLIDS... Any speed shop should be able to get you the Lakewoods.
-Jeb

 

OK as Jeb suggested, I have replaced the halfshaft U-joints with the new solids that were recommended. BTW, the old ones were Spicer solids. The new ones look considerably beefier, and very solid.

Now, I completed the install and was rotating everything to verify that all was in order. I satrt hearing a "clink, clink" noise, as I rock the wheels back and forth. It turns out that the driveshaft has play side to side between the yoke tabs. The straps are considerably stretched, and the U-joint caps have been rotating in the rearend yoke. Nice shiny line around the perimeter of both caps where the yoke tabs have rubbed during rotation.

Have any of you seen the straps "stretched" like this before? I compared them to a spare set I had laying around, and the bolt locations are where the give occurred. Does someone make a "girdle" for the mainshaft to rearend yoke? It also appears to take smaller U-joints as compared to the halfshafts. I am not positive at this point, as I buttoned it all back up. The car drives smoothly (~ 20 miles tonight), with no vibrations, but I will not run it really hard till this has been addressed?

Your thoughts on the cause as well as the fix would be appreciated. Has the long term abuse finally caught up to the driveline? Do I just swap the straps and be done with it? Are any of you running a different yoke, U-joint, and girdles on your D44?

Thanks in advance for your thoughts.

Aaron

 

Well just as a safety precaution I have always changed the straps when doing any type of U-joint replacement, be it half shaft or drive shaft. I have seen them stretch out like that before, I had a drive shaft universal fail on me on one of my 90's and it stretched out the strap or the strap stretched and caused the U-joint to fail not sure of the order. At any rate I replaced both and had no problems later. This was on my 383 car so it had some power behind it, not exactly what you or Jeb are throiwing at them, but not stock either. It saw alot of 5,000 RPM launches as well.

 

Van Steel sells a kit with solid steel caps instead of the straps. They sort of look like the main cap in an engine. The include new internal wrenching (allen) bolts for higher strength. They're not cheap, I think the kit was $275, but for piece of mind with the power you're making, it sure would'nt hurt.