First Truck

my truck makes a squeaky noise in the back off the truck i guess around the wheels. when i first start going?

it is around the back of the truck.its only when i first give it gas until it shifts. sometimes it doesn't do it sometimes it does. i had my brakes done about a month ago. it made the noise before, please help.
it sounds like a squeaky bed kinnda. it only does it when i first start going until it shifts.
also why does it shift hard when i slow down. i have a rebuilt tranny in my truck a year old or so.

could be springs.. go back to brake place its under warranty and tell them this they may find out whats up for free they will tell u

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