Is this normal in tow/haul mode?

[KennethWilson]

Just purchased a new 2005 CTD 3500 DRW 4X4 SLT AUTO 3. 73, to use for pulling our 5th wheel. One thing I've noticed is that when in TOW/HAUL mode when the transmission down shifts, it's like the transmission slips momentarily then locks in. I'm thinking this is the torque converter locking, but I'm not sure. Anyone else experience this?

 

[Idaho Native]

KW,



Have you done search on the subject?



I've felt the same thing and had the same thoughts you did. I do note that it shifts "harder" and seems to be a more positive hookup in tow/haul. Anyone else?



Loren

 

[BHolm]

Yep, thats normal. On downshifts you will get that second of un-locked convertor followed by a quick lock-up. On upshifts in tow-haul the 2-3 and 3-4 shifts can happen with the convertor locked giving you that extra firm shift. I am very happy with the upshift programming in T/H, much better than GM's T/H in that respect but it seriously lags behind the Allisons downhill grade braking feature for downshifting. Seems like they almost got it right for an exhaust brake, then gave up

 

[mberry]

Welcome to the TDR KennethWilson!



What you are experiencing is normal. The torque convert unlocks to shift, then re-locks. This helps prevent damage to the internals of the transmission.

 

[mberry]

BHolm beat me to the post!