I notice a slight slippage shifting from first into second, under mild acceleration. All the rest of the shifts seem great. About 600 mile on a 2024, 7.3L gas. Is this a break in issue that is likely to resolve itself or get worse?

 

I wouldn’t worry quite yet it will probably improve with more breakin? If not you have plenty of warranty left. Give it a few thousand miles first.

Good luck…

Mike

 

It's tough to say, everyone interprets things differently.
Is it truly slipping? Or is it a delayed/lazy shift?

I only have 250 miles on my 24 and have noticed once or twice the shift module seemed confused as to which gear to go to. I figure I'll let it learn awhile before getting too concerned.

 

About 800 miles on my 2024. Shifts smooth as silk.

 

Well.... You could describe it as a delayed of lazy shift it feels similar to the pause you get when shifting a manual transmission. Although the RPMs go up about 100-150 before it settles into 2nd gear

 

I will add that after reading your concerns, I paid particular attention to the shifting.
From a standstill on level secondary roads, normal acceleration, reaching a speed of about 40 mph, it shifted from 1st to 9th and I couldn't feel or tell when it shifted.
Maybe once yours has more miles, and is "broken" in, it will smoothen out more to your liking.