Alli question

[thechevyhdman]

My ally tranny has been giving me beef when it comes to down shifting. Generally with the tow haul OFF it will sometimes drop down a gear at 50 mph, not a problem to me. But the other day going down hill I tapped the brake once and bamm It dropped me down a gear or shut off TC at like 75. brought my rpms up to like 2700. Is there a way to prevent this. I bet if I did have tow haul on that wouldnt of even dropped down at that speed. Is this normal operation for the tranny at 75? I can understand downshifting at like 55 downhill but jesus christ brakes are cheaper than a new engine. Stuff like that makes me think Id like the ZF alot better. What gives Normal, or problem?

[Black Dog]

That is normal. The TCM will allow a downshift as long as engine speed will not exceed 4000 RPM. If the truck continues to accelerate, it will not upshift again until 4800 RPM.

[mark45678]

I have even noticed this with the t/h turned off coast for about 10~15 seconds and pick up speed it thinks its time to hold back! a cur is to just rest your foot on the accelerator . any tps input above 0% will keep it in gear and let it pick up speed!

[GMC-2002-Dmax]

Mine has done the same thing around 50-60 mph as well. Didn't think alot about it till you mentioned it but mine does it as well and I have the the busy shiftyness update installed already.

GMC ;)