Long story short I have been working on my first LS swap for a few months now, and finally finished it. 6.0 with H/C/I, long tube headers, 4l80, Quick Performance disc 9" all stuffed in a 91 S10. Truck sounds amazing, but on the first pull the front U-joint came apart and carnage insued. Driveshaft did damage to various things, but worst of all when it unloaded the trans it completely broke the bell housing from the block. My question is did this cause damage to the engine? As in force the crank forward??? Is there a way to check for this? I have lifted the body from the chassis, just as I did for the install, so access would be easy.

 

Any idea what rpm it was turning when the u-joint failed?

 

5K ish. Was on a nice pull, curve looked great and was pushing 400 already.

 

Doubt it hurt the engine, I would be more worried about the front pump in the transmission

 

Kinda doubt it hurt the engine. Only way to know without a tear down is simply start the engine and observe/listen. Can you support the engine under the oil pan, and do a startup with tranny off?

 

holy sheeit man i didnt even know that was possible. Is there anything we can do to our transmissions to keep that from happening?

Are the dowels in the bellhousing?

 

Ive seen this a few times. Think the threads are on this site, but might have been t56 cars instead of autos. A steel bellhousing will prevent this. Always carnage when a driveshaft goes AWOL.

edit....One was an aluminum block and it took the block out as well...

 

I had hoped to pull the trans and run the engine to listen and watch oil pressure, but couldn't get to all the bell housing bolts, this is tight in an S10! So the body came off once again.
Already installing a TH400 I had sitting around. It is a Reverse pattern manual valve body with a brake unfortunately, but the good news is it was built for a big block I had with 644hp at the crank and a 250 shot to boot, never completed the car it was intended for. Should hold up just fine....
4L80 is junk now as far as I'm concerned, will keep the brand new converter obviously (or try to sell it), but it's not even usable as a core.

 

How much did you BFH mod the tunnel? I beat the living **** out of mine

 

Actually did not have to do any tunnel work to it, fit like a glove amazingly enough! I will be slicing and then laying back the seam from the firewall to the tunnel this time just to make it a little roomier. Hopefully if I decide to go back to a 4L80 I wont have to lift off the cab, at some point here a cage is going to be necessary making cab removal a thing of the past. With any luck I will be getting kicked off the track sooner than later and need a cage!

 

Is the motor and trans solid mounted? Or is one solid mounted and the other isn't?

What a bummer. Hopefully you get up and running soon.

 

Both on standard rubber mounts actually. Should be on the road this weekend!

 

LMAO. I did this EXACT same thing to a customers truck I was dyno tuning. I had made multiple pulls to 5500. Decided to make a pull to 6k. I still don't know if it happened at the end of the pull or when I let of the gas.

**** got real loud REAL quick.

Twisted the driveshaft in half, spit it out the back. Trans tail shaft vaporized, broke the trans in the same way.

And this people is why you sign a waiver form. HAHA.

 

I think that's a moot point all things considered....

 

Yeah make sure the u joints are good and the driveshaft is balanced....

 

I didn't see it mentioned but to be on the safe side you might want to check the rear end to make sure it wasn't damage and make sure it wasn't the cause.
The few times I've seen transmission damaged like that it wasn't due to U-joint failure. The U-joint usually failed because something locked up causing the joint to fail in the process. My guess is that the trans failed but that's just a guess lol.

 

Do you think before you post? Iinternet never quits, I swear. "Hahahahaha customers u joint failed while I was dyno tuning it and caused $2000 in damage hahahaha" is how that sounds. Signing a waiver doesn't help a customer, I don't understand your post. "Here's your fucked up car back hahaha, that'll be $400, thanks for signing the waiver hahahaha".

Op, sucks it happened. I feel for you.

 

Occasionally I have had to dyno trucks in 2nd gear instead of 3rd because rev limit pulls in 3rd put the long driveshafts way over critical speed. Last thing I want to do is eat flying driveshaft parts while sitting at the dyno control computer.

 

It's alive! Buttoned everything up and took it for a drive last night. Traction is non existent in first gear anywhere, second is marginal.....I have never driven anything that is a bigger handful when spinning, the short wheelbase is sketchy!!
Hoosier DR2's going on it Thursday, and hitting the track Friday God willing!!!! If I could get video to post I'd post a quick one of it idling....

 

just video it with your phone