2G Pump whine and "soft" park?

[bmxfelon420]

Hey all, been running my car for almost a year pretty trouble free, then last Saturday I pull away from a stoplight and hear a whining noise. I noticed that it slips a bit when this happens. If I give the car very little throttle it seems to not slip and accelerate ok. When cruising at speed there is no notable noise. The transmission still shifts into all gears and lockup just fine. The noise is not present when in park or Neutral. The only thing I noted that was at all out of place was my fluid level when hot was a bit high. I drained about 3/4 quart out of it and it's back in the right range.

Second problem that popped up when this happened: Park is now acting more like a brake than stopping the car at all when stationary. If I put the car in park, it can creep very very slowly. Not enough to notice at first, but I went inside for an hour, came back out and the car rolled back two feet.

I'm at a loss and wanted to see what anyone's opinions were on what this could be. My current plan is to drop the pan, inspect everything, replace the filter with a new one, and new fluid. If it still has issues after this I was going to pull/inspect the pump and swap it with a pump from my parts transmisison. My theory as to the sudden slipping is that the filter is either clogged, defective in some way (I replaced it last year), or the gasket between the filter and the transmission is leaking and the transmission sucks air on occasion instead of fluid. Here's a video of the noise and behavior, any ideas or suggestions are welcome.

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[CrackedDSM]

Dropping the pan and checking the fluid/magnets will tell you a LOT. If everything appears kosher and there's just your average clutch material on the magnets, then it's most likely just a filter/fluid problem, but I would still inspect the pump anyway. If you take the torque converter off, and shine a light, you can see into the pump itself. It'll be very obvious if it's worn or not. If it's a little worn, that's okay, but if the bearings are being eaten into, and/or there's a severe amount of wear...then the pump is bad and needs to be replaced.

The car moving in park is a dead giveaway of something. I'm having a huge brain fart right now though, I'll remember it later.

 

[hotrodssnova]

I put my auto in without the back axles and the car would roll backwards. I then put the axles on the back and park would work just like it should. Just thought I would throw that in. Sounds like you might have an internal issue there, like maybe the vc, or center differential.

 

[bmxfelon420]

Hmm yeah I'm wondering that as well, I'm trying to swap torque converters this weekend just to see what happens, I'm not expecting much, but if it can limp along until I can get the other transmission rebuilt that's good enough.

 

[hotrodssnova]

Swapping the tc won't fix the rolling in park. Park is a mechanical lock.
Replacement of the tc will let you inspect the pump bushing and check the pump, kinda.

 

[bmxfelon420]

Swapping the tc won't fix the rolling in park. Park is a mechanical lock.
Replacement of the tc will let you inspect the pump bushing and check the pump, kinda.

Yeah I dont really expect it to fix the park. I just want to get it along for long enough to fix the other one really.

 

[bmxfelon420]

Ok, did some work to the car last night. We drained the fluid, and replaced the filter and fluid. Things of note:

-Fluid looks burnt. No metal flakes in it though
-Magnets only had a small amount of stuff on them
-Front wheels move freely in park when jacked up

Based on the noise it makes (after the fluid/filter change) and the specific behavior of the car (it only making the noise under load/takeoff, the sudden loss of park, and the smooth shifting/driving/operation of everythign otherwise) leads me to believe that the most likely thing that has happened is that the center diff has failed, and no longer biases any sort of power/torque from front to back. As far as I can tell, if the transmission itself was in park, and this could still move, that would allow the rear wheels at the very least to still roll. Also this makes sense because when cold, the car holds in park. I'm wondering if the center diff is tight enough after it has sat for awhile to be able to stay in park. As soon as you put it into gear after that, it will be able to roll, with varying degrees of speed, again.

The reason I doubt other failures is that if it were a pump, there would probably be more debris in the fluid, and also very likely problems going into gears. I have no issues at all in terms of shifting. It shifts perfectly. Also, and I didnt really pay any heed to this before, but I wonder if the center had failed in the locked position all along. I noticed that when making 90 degree turns, the inside rear wheel would chirp a bit. I thought that maybe it was just a bit tighter than the diff in my Talon, so I didnt pay it any mind. Now i'm beginning to wonder if it had failed at some point in the past, locked up, and now finally gave way. If my understanding of the setup works, this would explain why park is loose, the wheels themselves can still move that diff, which no longer stops them the way it normally would. I did some research on viscous coupler failures and one of the tests is to see how much torque it takes to spin it, and if it below a certain spec then it has failed. This exactly describes how it currently operates, because under very light throttle/load situations, it works, when more throttle/load is applied, it slips and makes the noise.

So for those reasons, since it's so easy to replace the center diff anyways, I pulled the entire assembly out of my 95 transmission so I can swap it next weekend. From what research I've done, the transfer case itself is different between early/late 2g's, as well as the gear that drives it, but from what I can find the diff itself isnt different. If there's any reason anyone can think of that I cant just use the whole thing, let me know. It's not a big deal to swap something over to the old stuff, as long as it fits ok. I was going to count the teeth on the splines/gears on both of them before we even took the "bad" one out.

 

[bmxfelon420]

Did some more digging on this today. I tore that transmission 90% apart and found that the parking pawl works perfectly and is locking on fine. The slip is happening after that. What could possibly slip on the output side of the transmission?