Hard downshift into 1st gear

[dward]

I just completed a 5k mi trip with my new 21 3500 QC 4x4 DWR 68RFE and Arctic Fox truck camper.
These new trucks are Sooo much nicer then the older generations. With a camper weight of around 5k lbs, I'm only using Timbrens and it handles like a dream. The 50 gal fuel tank makes for a 4-500 mi range.
About half way through the trip I began to notice a harsh downshift into first gear when coming to a stop. This only happened when tow/haul mode was engaged.
So far I'm really happy with the 68 trans and don't regret not getting the Aisin.
Any ideas what can be causing this or anyone experience it?

 

[SSchang]

Did you have the exhaust brake on? That will cause it to feel like a hard shift as you slow down for a stop.

Scott

 

[HVAC2]

Did you have the exhaust brake on? That will cause it to feel like a hard shift as you slow down for a stop.

Scott

 

[HVAC2]

Sounds normal on EB.

 

[dward]

Yes, the EB was on but it didn’t start shifting that way until half way into the trip.
With the EB on and not in Tow/Haul mode it shifted smoothly.
It seems more abrupt then I would think. Almost like downshifting too soon with an older auto trans.
I’ll try without the EB and see how it shifts.

 

[SSchang]

Tow/Haul mode keeps the rpms higher which makes the exhaust brake more aggressive.