4eat go boom?

[snowcat]

I'm at a traffic circle, waiting to go, and once it's clear and I start to go I get this huge wump 3 times, as if I hit something. Car won't go anywhere. Shift back and forth b/w r and d and nothing, both w/manual button engaged and not, nothing in all drive gears, l to h. Sometimes the 3 wumps happen again, both in r and d, car hitches like it's gonna go, then nothing. Parking pin whines/grinds as I go back in to park, but then car still rolls.

I connected the fwd only, but nothing. Friend says cv joint or drive shaft, but I'm thinking if car rolls in park can't be good.

94 turbo legacy, 4eat trans, w/just about 140k, driven pretty conservatively. I've done a few fluid changes in the 7-8 years I've owned it, the last being all fluid out and then idemitsu/subaru fluid in. I've heard that this can be bad, but after years w/no driving problems and several changes I really wanted to put all subaru fluid in.

Fluid level is fine, looks/smells clean. VSS 1 and 2 errors from the tcu and a neutral switch error from the ecu, and 2 maybe 3 tiny slips in the last month or so. Was running a trans cooler for a while, then took out after doing new radiator, water pump, timing belt.

Usmb says legacy trannies rarely fail. Thoughts?

[Alphius]

Front CV busted or hub splines are stripped. The telltale sign of something wrong between the tires and the transmission is the ratchet/grind noise into park. That means the transmission output is spinning but you're not getting anything to the wheels. I'd say the "whump" noises are the center diff trying to limit slip and transfer to the rear wheels but it can't transfer any torque to get the car moving if there is absolutely no traction at the front axles due to a mechanical problem.

EDIT: Suppose it could be a bad front diff too.

[Legacy777]

Well you can easily rule out a cv joint or something external to the transmission by just looking underneath.

If you don't see anything, the problem is internal to the trans, and in which case, I'd say it's probably time to find a new trans.

[icrman]

Next maybe the ring and pinion or differential, like teeth missing or?