I would have to say that from the lack of responses nobody has any idea.My FJ cruiser is from 2007. It has around 90,000 miles on it. Every say 20 minutes the back will shake for about 5 seconds. It happens no matter what speed i'm doing. Does anyone know what it could be?
I would think the transmission could be slipping before I would suspect a differential, but I'll let one of the experts comment on that. That could cause a shudder through the drivetrain.I drive all over NY. Long Island, Manhattan and Brooklyn. If I'm driving for an hour it happens a few times. When I drive short distances like 10 minutes it may or may not happen. It will happen whether I'm going 5mph or 60mph.
I took it to a friend and he said it could possibly be the rear differential but he doesn't check that kind of stuff so he wasn't sure. Toyota wants $125 just to look at it and tell me what could be wrong.