Torque wrenches and extensions?

[dlundblad]

My bands in my 42re transmission are about due for an adjustment. I have read from a few sources that say to to torque to 72 inch lbs, but if a 3" extension is needed, torque to about 47-50. Is this conversion correct?

The last step in the process is where a 40 Torx bolt needs to be held in place while the nut needs to get torqued to 30 foot lbs. IIRC, a crow foot wrench is needed. Would that make the torque settings fluctuate at all? Very confusing stuff.

Thanks fellas!

 

[paulo57509]

The only time you have to be concerned with re-calculating torque settings is when the "extension" changes the length of the wrench.

http://www.belknaptools.com/support-library/extensions-calculator/

 

[Rand]

if you have a normal right angle torque wrench it doesnt change the length of the wrench.

 

[Chris142]

a 3 inch extension wont change the tq any at only 72 inch lbs

 

[ecotourist]

As the link defines an extension the torque would need to be adjusted. The torque arm gets longer.

As most of us would think of an extension (ie a longer shaft at right angles to the applied torque) it wouldn't make any difference. The only fly in this ointment would be keeping the shaft at right angles to the applied torque - though I can't imagine even that making much difference.

Ecotourist

 

[AITG]

If the crow foot goes on the torque wrench, try to keep it 90 degrees from the handle. That keeps the overall length the same so no adjustment is needed. OTOH, if the crow foot is holding the other end of the fastener, don't worry about it.

 

[Rick in PA]

What do you mean by " 3" extension"?

One of these would require NO conversion:

One of these WOULD require a conversion:

 

[JHZR2]

Is it going to change the angle of the head/lever arm/fastener?

 

[Merkava_4]

Originally Posted By: dlundblad
I have read from a few sources that say to to torque to 72 inch lbs, but if a 3" extension is needed, torque to about 47-50. Is this conversion correct?


The author of the book should have said 3 inch Torque Adapter instead of "3 inch extension."

A Torque Adapter looks like a box end crows foot and will increase the leverage if used.

 

[andyd]

Heh Heh. 72 inch pounds is about 6 foot pounds or gudentite with a socket stuck on a 1/4 " nut driver. Don't they get backed off a 1/4 turn after the torque spec is reached?

 

[clinebarger]

The SPX/Miller adaptor part# is C-3705, If you have a small 1/4" drive flex head inch pound torque wrench....You don't need the adaptor. The Jamb nut torque is not so important.

 

[morris]

from what i understand torqueing the adjusting screw to 72 in lbs is just take the slack out of the linkage. i think in a pinch you might get by hand tighting it. DO NOTE: iam NOT a tranmission expert. iam just making an uneducated guess. as i have a about a dozen chrysler factory service manuals all show the 72 in lbs. but the number of turns for different bands vary some what.

 

[dlundblad]

Originally Posted By: morris
from what i understand torqueing the adjusting screw to 72 in lbs is just take the slack out of the linkage.


Ah this makes more sense now. So a good comparison would be winding up a clock? More or less.. Maybe backwards?

And yes that torx screw is then backed off so many turns depending on what transmission you have. Then the nut is torqued down to 30 ft lbs while the screw is held in place..

IIRC, the last torque setting also depends on what transmission you have.

A car lift and a good light source are a must here.

As for the extensions, I did mean a drive extension. Thanks for the clarification guys.

 

[another Todd]

Originally Posted By: Rick in PA
What do you mean by " 3" extension"?

One of these would require NO conversion:

One of these WOULD require a conversion:

What Rick said is correct.