Torque limits

[JayR]

Me and a friend are working on a Dodge automatic transmission. We need to torque the output shaft nut to 200 lb ft. If we use an electric impact wrench how do we know when we reach 200? I can't find a torque stick higher than 175.
A supplier will sell us the holding tool from Dodge, but we are on a tight budget! Maybe we could jury rig a holding tool and use a manual torque wrench.
What are some recommendations?

 

[mrholeshot]

Hold the yoke with a big pipe wrench and torque it down

 

[ozzy214]

Have to buy a torque wrench to do it right. But I can vouch watching trans builders, they do it by "feel" So hammer it with gun. 175 is a lot and most guns top out about that depending on aiir compressor, line size, etc. So I would say hammer it on and forgot about it. Like I have a super duty ir 241 over 20 years old. Supposed to be 400 ft lbs torque. I can vouch tighest run it will be is 180 hammering for a few seconds.

 

[4000xt]

Get a tourque wrench and torque it properly than you dont have to worry about it. You must be able to borrow a torque wrench or rent one for cheap.

 

[Moose-LandTran]

Hold the yoke with a big pipe wrench and torque it down

We have a winner!

 

[tyreguy25]

Run by AutoZone and rent a Tq wrench.

Most of these impact power ratings are breakaway torque rather than applied torque.

 

[JayR]

Thank you gentlemen. We have a torque wrench, but not a good way to hold the shaft. The thinking was that an impact wrench does away with needing to hold the shaft.
Thanks tyreguy25 ... I didn't think about breakaway vs applied torque before your comment.

 

[Toolhorder]

If it's the output shaft can't you just put it into gear to stop it from moving?

 

[JayR]

If it's the output shaft can't you just put it into gear to stop it from moving?

The transmission is out of the car. But I'll see if the torque converter turns when I turn the gear. I doubt it, but a test is worth a thousand opinions.

Thanks for the idea.

This whole project is to learn something about automatics. We are starting from ground zero

 

[mrholeshot]

The transmission is out of the car. But I'll see if the torque converter turns when I turn the gear. I doubt it, but a test is worth a thousand opinions.

Thanks for the idea.

This whole project is to learn something about automatics. We are starting from ground zero

The only way to stop the tail shaft from turning is to put it in park. You don't want to torque the tailshft in park or you risk sheering the parking pawl. While it doesn't seem like that is a lot of torque for something that holds the truck from rolling down a hill it really doesn't require that much. It's the reason that vehicles have parking brakes. I wouldn't put that much pressure on the pawl needlessly. Use the pipe wrench on the yoke. While most guys who rebuild them for a living do it with an impact they have developed a feel for it. You don't want to screw up your ****** or risk the yoke coming off so do it the right way and torque the nut down to spec. If you start trying to cut corners now you will be doing it the rest of your life or learning some real expensive lessons on how to do it the right way the next time around. A local reat a tool can rent you a pipe wrench big enough for just a few dollars

 

[Charles (in GA)]

If it's the output shaft can't you just put it into gear to stop it from moving?

Its an automatic. Without hydraulic pressure generated by the front pump, the ****** is in neutral.

Putting it in part would lock the output shaft to the case, then they would have to keep the case from rotating during the torquing. As noted, use a large pipe wrench or strap or chain wrench and apply the torque.

Charles

 

[glenmore]

Just an aside, I read that in the F1 pits, the torque applied to the wheel nut is about 700 ft-pounds!