Strange noise during cold start on Powerboost

[Gros Ventre]

I took delivery of my truck very late June 21. That October, when temps got down to around 15ºF, transmission noise on starting when cold soaked overnight. After a bunch of troubleshooting and experimenting, it turned out to be a somewhat underfilled transmission from initial assembly. The temperature effect was simply that of when temps were down enough (EG < 15ºF) something uncovered from fluid contraction and the transmission then had something cavitating. As it warmed up the expansion of the fluid slowly fixed things. Adjusting transmission fluid level was the fix (and not necessarily easy for a tech doing it the first time). They reached a time when the truck would run on the lift but would not go into gear or move (apparently the memory "knew" something was not correct). After they got the level correct, it still wouldn't move. They tried to reset the computer but no go... until I remarked to them that the small battery also had to be disconnected to reset the memory circuits. They did that and off we went! No issues since (And my work effectively trained their techs on how to adjust transmission levels).

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