How to do a proper auto trans dyno?

[PatrickCampbell]

I would think the proper way would be to get it in 1:1 gear (3rd) and lock up the torque converter and punch it at about 800 RPM.



Is this correct, if so, how can it be done? I went on a dyno and they gave me a run from 2000-3600 RPM and I don't even know if the TC locked up... 2000-3600 is not useful to me when my truck rarely goes over 2200 RPM!



Anyone messed with the ECM/TCM on the 48RE?

 

[XJSuperman]

The 48RE is suposed to lock up at 49 MPH... which in 3rd gear (DRIVE) would be near the 2,000 RPM range with stock tires (31. 4" tall) and 3. 73 gears... the 4. 10's would put you at about 46 MPH BUT add about 50-100 RPM and you're there.

So if they printed your graph there should be some MPH figures there somewhere and you'll see you were at 50 MPH or better during most of the test which means the converter should have locked.

 

[BIG BOB]

From my understanding, when I dynoed my truck you do the following.



Lock out overdrive, go through the gears when the torque converter locks up in 3rd (about 50 mph), back off the throttle slowly to you get down to about 1300 to 1400 rpm, then roll on to the throttle (don't hammer it, it will downshift into 2nd) for about a second or two then put it to the floor. It should stay in lockup and you should have a good run.



Hope this helps!



By the way DIESEL THUNDER is tomorrow! Oo. Oo. Oo.