I think I hurt the transmission...

[Tim_K]

Might have broken something in the 904, tell me what you think. A few days ago, while pulling out of a parking lot under mild to moderate throttle, the right rear wheel went off the pavement, into a dirt ditch about 8-10 inches deep, and back up onto pavement. A pretty hard hit. A guy I know blew the spiders out of a 7-1/4" axle AND destroyed the sprag in his 904 about a year ago doing this same kind of trick.
For the rest of the afternoon, I noticed no problem. Drove in traffic and on the highway at up to 75 mph. Stopped by the library in the evening, and when I went to leave, trouble started.
I started the engine up, and when I put it in Drive, I started hearing all kinds of loose metal sounds, like the factory sheet metal converter shield was vibrating around loose. I don't have one of those on my 904, so I knew that wasn't it. While in any gear except Park or Neutral, even when sitting there idling and not moving, the car had a whole new strange shaking vibration to it. The flashlight wasn't working, so I drove a few miles to a gas station parking lot which was lit up. More of the same metal sounds. One time when I moved the shifter fron N to D it stalled the engine. In the parking lot there, and later in the lot at home, I was testing it. At low speeds, like taking off from a stop, it'd have a weird shake, like the clutches were grabbing and releasing several times a second. Something's wrong. The fluid was full and clean, nothing's leaking, and the converter to flexplate bolts are all there.
I'm driving it again today, and haven't noticed any problems. And I've been really looking, too. My 1973 shop manual says possible inner race of the sprag problems for what's happening. So why didn't it happen today?
If it's bad, I won't know until I take it apart or it breaks down on me. It's no big deal to tear down a 904, but it's just something I don't have time or money for right now. I could get another bare case with a good sprag in it, and just swap all the internal parts to another case and be done with it.
I've never really understood what a sprag does anyhow, except they explode the front drum when they go bad in race cars.
So who thinks what about this?
This is a non-lockup wide ratio 904 in 1 1971 /6 Valiant that runs low 16's. MP 175K cheap junk converter.

[Tim_K]

It only stalled the motor once. The transmission has been fine for the last few days, no noises or shaking, except for once today. Heard the rattle for a couple seconds while coasting down at low speeds (20-30 mph).
The convertor is a P.O.S. MP unit. A 175K blue light special, cost $187.00 new. Quality? Service? I don't think MP knows what those words mean.

I was wondering if maybe I flat spotted the sprag rollers, and once they turned and started fully locking again, the problem went away. I've already got plans made to swap in another sprag, but the problem is how/when/where to do it. My mopar friends' house, where the big work gets done, would be hard to do. They're not going to want to have me go in and pull the transmission out if the car is still able to move on its own. I'll hold down the street racing until I figure this out.
Converter seems to be working ok. Cruise rpm's are unchanged.
When I first heard the noise, I thought it was the power steering pump. It sounded like it was around the front of the transmission, not down inside. Converter sprags going bad like this? I've never heard of that before.

It was doing the metal sounds again today. It does it while coasting down to a stoplight. I have the kickdown linkage set back pretty far, so the transmission will downshift from 3 to 2 to 1 as I slow it down. The noise starts at about 20 mph (engine idling, car coasting), and continues down to about 5 mph.
I'm thinking converter now also, but I'm still going to be paranoid about the sprag in the transmission until I check it.

[tsteiner61]

Sounds like the sprag to me.

[Glen440]

I had a couple weeks ago my lockup converter got stuck locked up. I had no choice but to smoke the lockup out of the converter to get it home. Before that I took the valvebody all apart and put back together to see if a valve was stuck. Try putting a tranny in gear with the converter locked up........felt like the rear end was gonna get ripped out.

[Tim_K]

I bought this converter from Mancini, will they replace it? Or do I have to deal with MP?

[John Kunkel]

I think you have a sprag problem but not the sprag in the trans, the sprag in the converter.
If the sprag in the trans failed it wouldn't kill the motor but if the one in the converter does, it can stall the motor. The failing converter sprag can also cause the shaking like clutches grabing and releasing.

[DartByU]

When I had a 904 in my Dart behind a mild 318 it started having a vibration that would come and go, then then a few days later during a hard 1st to 2nd shift something broke, towed it home, took it out and discovered the stock flexplate had broken into about 4 pieces. That's when I went and bought a good B&M flexplate for it.