Fresh 904 start-up

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HTMLmopars

HTMLmopars

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Just getting my 5.9 Magnum swap installed into my 68 Valiant and trying to figure out what I need to do with my fresh built 904. I prefilled the converter (stock) with a good amount (honestly don't remember how much but I believe it was over a quart) and installed it all.
Like I said this is a fully rebuilt transmission, so I expected to need 8+qts to fill it up. I got about 7 into it and it was full up into the dipstick tube. (This is all before firing the engine at all)
I left that 7ish qt in it and fired the engine in neutral, somewhere in this forum I read that the trans pump runs while it's in neutral so I figured it was a good bet. I still have fluid up the dipstick a long ways after running the engine for over 15 minutes.
I'm nervous to put the trans in gear because I don't want to starve it if fluid and cause a problem, but I would guess that it needs to be run through the gears to get the fluid throughout the trans.
Am I missing any steps or is the next step to put the car on jack stands, run it through the gears and keep the fluid full?
 
Don’t be nervous, put the bastard in gear, how do you think the factory or trans shops do it? You have to put in gear, or just stare at it and never drive it.

You can drive it on the driveway and then check the level in neutral. Don’t need to raise it, just don’t get aggressive with the throttle Until it’s for sure full. Take it for a short drive and check again. Always check level in Neutral.
 
That's the confirmation I was looking for, lol. I have about 10 other projects on the car to get it roadworthy, so I haven't actually lost any time staring at the trans. Just wanted to confirm I wasn't missing something obvious
 
I start it in neutral and let the pump fill everything up for a few minutes. Shut it down, recheck level and let it eat.
It doesnt hurt to let your car idle in neutral for a few minutes before driving it.
 
68Valiant225 said:
Just getting my 5.9 Magnum swap installed into my 68 Valiant and trying to figure out what I need to do with my fresh built 904. I prefilled the converter (stock) with a good amount (honestly don't remember how much but I believe it was over a quart) and installed it all.
Like I said this is a fully rebuilt transmission, so I expected to need 8+qts to fill it up. I got about 7 into it and it was full up into the dipstick tube. (This is all before firing the engine at all)
I left that 7ish qt in it and fired the engine in neutral, somewhere in this forum I read that the trans pump runs while it's in neutral so I figured it was a good bet. I still have fluid up the dipstick a long ways after running the engine for over 15 minutes.
I'm nervous to put the trans in gear because I don't want to starve it if fluid and cause a problem, but I would guess that it needs to be run through the gears to get the fluid throughout the trans.
Am I missing any steps or is the next step to put the car on jack stands, run it through the gears and keep the fluid full?
Click to expand...

Go through gears. Put back to neutral and re check fluid level.
 
I fill the converter and start at two gallons in the transmission. Then add as needed.
 
Also, I do believe the level has gone down on the dipstick since firing the engine, it's still high but not as high as it was. And I trust the trans builder more than myself. I assume I'm being paranoid but I just wanted to check that I hadn't missed anything obvious. The likelihood that I can't count how many quarts of fluid I put in to it also seems high.
I'll have an update either tonight or tomorrow. Been one of those weeks where I can't stop thinking about the problem but also haven't had the time to work on it
 
Is it a new converter? I have heard of situations where slag from the welds on the inside of torque converter have broken off and ended up in the pan / filter on after the first fire up and run. If you're a little paranoid (like me) you'll want to pull the pan after the first fire up and run through the gears to make sure nothing has been broken loose.

I've never seen this myself, but after hearing about it from two different sources I now check the pan after installing a new converter.
 
Personally the TF is a pretty forgiving trans…. Unless the magnet looks like a porcupine egg, run it! ;)
 
Get her up in the air today. Goes in and out of gear good, it'll roll forward and backward while idling. Car still needs some work before it goes on the road to test but I think we're fine. Fluid level is down a bit but still a bit high. I don't think it got in to 2nd or 3rd, so I'm not sure if all the passages opened up to the fluid yet
 
If you've got it up on good, safe jack stands, start it up and hold the brakes. Put it into drive and while still having slight pressure on the brakes, give it some gas like your pulling off from a stop. Holding the brakes gives it enough resistance to simulate rolling resistance like driving. You will be able to feel it shift gears. It should change at 18 mph from 1 to 2 and 28 mph from 2 to 3. Be sure to hold the brakes hard enough to get the back wheels to stop before you put it in park. :eek:
 
That's high enough to aerate the fluid. It has to set overnight for the bubbles to come out. The drums will still spin in the fluid even if the pump is broken. Make sure it's at least to the full mark in neutral and drive it. Warming up a trans for 15 min that isn't full often destroys it.
 
I'll pull fluid out of it tonight to get the level down. On Saturday I had the car in the air in gear, when all of that went well I put it down and then let it idle back into the garage. Moved about 1 car length. It seemed like the converter worked normally, it idled up and in really easy. I know I didn't pre-fill the converter to FULL full, so I would tend to think the pump is working because a low converter would have a higher stall than it should.
 
"A low converter would have a higher stall than it should"?!? NO. There's a lot of bad info out there. If there isn't enough fluid to fill the converter, then there surely won't be enough fluid to apply clutches or bands. Run it about 1/2" above full. Just remove the neutral safety switch to drain out any excess. And set the kickdown so it's at max when the carb is at max.
 
CudaFactHackJob said:
"A low converter would have a higher stall than it should"?!? NO. There's a lot of bad info out there. If there isn't enough fluid to fill the converter, then there surely won't be enough fluid to apply clutches or bands. Run it about 1/2" above full. Just remove the neutral safety switch to drain out any excess. And set the kickdown so it's at max when the carb is at max.
Click to expand...
Was based on my experience when I had to limp the car home with a fluid leak (I'm smart enough to not do this again), it felt like my converter was getting looser and looser as I went. To verify pump functionality could I pull a cooler line to see if there's pressure out?
I hate this "maybe it's a problem, maybe I'm an idiot who can't count how many quarts are in it and is too worried about it" and the car is weeks from being safe to drive down the road. If I need to have the trans fixed, I'd rather pull it now and then do suspension work.
 
If it’s that overfill the remove the speedo housing or NSS to drain it down.
 
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