Everyone always talks about how big power, hard launching cars put stress on the trans tailshafts when the torque arm loads up. That makes sense, but are these things really breaking all the time? Or is this talk just from people wanting to sell $600 torque arm packages? I've actually never heard of anyone breaking or cracking a tailshaft, so I suspect this is partially just hype. But what about you all? Ever seen anyone with this problem? How fast were they going? How fast have you seen people go with trans-mounted set ups? I'm sure an 8 second car would have problems, but what about 9s, 10s, 11s...?

 

I ran low 10s on the stock setup, built 700R-4, ES poly bushing for the torque arm, ES poly trans mount. Best run was a 10.21, at full street weight, full interior, 3.73:1 axle, custom torque converter, 26" drag radials, self-ported Vortec heads, custom roller cam, Super Victor Vortec, 355 cubes.

 

It depends a lot on the car and traction. Figure the TA does pull up a lot on the tailshaft, and the trans mount. Its enough to break the trans mount in a stock vehicle. The tail can fail, its the honest truth. You don't have to spend huge money on a complete torque arm setup either, you can get just a relocation crossmember to use the stock or stock fitting TA, that wil simply move the stock mount off the trans, pretty sure all 3 UMI, BMR, and Spohn offer these parts.

 

Tru dat on the trans mount. I broke 2 stock ones before getting a poly one from Energy Suspension. It's been holding strong since the early 90s.

But it sounds like a trans mounted arm worked fine for Atilla in the low tens. That's all I ever hope to run with my current setup, so I hope that will work for me too. I just can't fit an aftermarket crossmember with my stupid dual exhaust.

 

Bear in mind that I wasn't shock-loading, my best 60 foot was around 1.9 seconds, which isn't all that good. Use a hard-hitting converter, you can do damage with an 11-second combo.

 

Does anyone have any actual real world examples of these things breaking? That's what I'm looking for. So far, this is all hearsay.

 

I could see a benefit of having a relocation mount crossmember to use a non-Fbody tranny like just grabbing a tranny out of a Caprice/Truck/whatever to use.

And no.....I've never heard of a tail shaft breaking but I also don't run in drag racing circles either to hear of any.

 

I asked about this little while ago and got some good answers. It does help in coming out of the corners when road racing because there's more of an immediate feel when accelerating. The car is less squishy when accelerating. And the tail shaft is apparently weak but that I cannot confirm, although it makes sense.

 

I know a guy who grenaded his T5 at Texas World Speedway going into T10 (CMC roadrace car).

There's a slight rise at the braking zone. He axle hopped pretty bad and it resulted in a destroyed transmission.

 

I don't think Gman is talking about what we're talking about, but I got a chance to ask a big reputable transmission shop about this recently. They said that they have never seen a 700r4 tailshaft break -except in 4x4 trucks. And that points out that if the trans can take the weight and stress of a transfer case (although it is reinforced and braced), then our torque arms are probably not going to rip them off.

 

When my 83 was still bone stock, almost still new, the trans mount broke... I put a new one in it, backed down the drive way, launched the car hard, and broke the new one THE VERY FIRST TIME I let out the clutch.

So, yeah....

Never seen an extension housing break. Seen a few with stripped bolt threads, but that's probably mostly from ineptitude on the part of whoever last assembled it. Of course I've only seen a few dozen of them, probably not much more than 50, so not necessarily a very representative sample...

 

Cracked extension housings aren't always from hard launches. Constant vibration or repetitive motions that push and pull on the housing through the mount bolts can be destructive over a long period of time. Or incorrectly reassembled stuff can lead to breakage. Yeah, I've seen a couple broken ones but no, they're not an epidemic.

As for $600 aftermarket parts, your signature is pretty ironic.

 

I don't care how much it costs. In fact, I would much rather have one of those since the trans mounted ones are so hard to install/remove. But those aftermarket crossmembers won't fit with my stupid dual exhaust.

 

I want to believe this is mostly irrelevant as the transfer case bolts to a short adapter and then to the trans where the tailshaft housing would bolt on. In the trucks this is supported by a crossmember under the transfer case not the transmission. This greatly changes the weights and stresses seen at the trans by the transfer case.