904 help, won't move

-
Freezerman

Freezerman

Well-Known Member
Joined
Jul 4, 2013
Messages
318
Reaction score
114
Location
MN
My son and I are putting together an 84 D150, 5.9 magnum, original lockup 904 with shift kit. Drove great 1st few test runs. Now it engages drive and reverse but won't move unless revved up. Put in a new torque converter, no debris in pan. It blew the pressure fitting at the radiator, pump is good sprayed all over. Tested, zero pressure drop through radiator and back to transmission. Reads high on the dipstick even though i know it is a quart low.. something plugged in the valve body?
 
I would start by jacking up the rear and making sure you can actually turn the driveshaft and tires in neutral.
 
I would put a gauge in the test ports and check the actual pressure. I had one snap the lugs off the trans pump gear, and had problems at higher rpm.
 
Thanks for the replies. I have tried moving the wheels in neutral, spin easily. Gauging the test ports is in the plan, just need to get the equipment together. The truck will move a little when revved high (3 to 4K). The fluid level shows high even though I'm actually still a quart low from what the book calls for. Is there something in the valve body that would stop flow to the torque converter? I can feel the drums engage when shifting in and out of gears.
 
My thoughts are that if the fluid level is high, the pump is not pumping correctly
 
That's what I believe too, when there was more fluid in it, the level was 1/2 way up the dipstick. But there is enough pressure to make a hell of mess when the fitting on the radiator came loose. It's like the convertor isn't filling up. Same issue with old convertor as well
 
Can't go by the book for fluid level on a trans have to go by stick reading

But I'd go with lugs sheared off pump drive been there before.
You say yours came with a 904...... if that's so then how did my 85 d150 end up with the 727? And yeah I have verified it's original for this truck....
 
These are all 85 truck trans numbers so yep, many with 727s.

4058384 4058384 225 727 LU, Long Ext.

4295941 4295941 225 727 Non-LU, Long Ext.

4329438 4329438 318 727 Non-LU, HD, Long Ext.

4329458 4329458 318 727 Non-LU, 4WD

4329482 4329482 318/360 727 Non-LU, Short Ext.

4329468 4329468 318/360 727 Non-LU, HD Long Ext.

4329488 4329488 360 727 Non-LU, 4WD
 
@VOETOM thanks for chiming in. Since you did, I have sent you 2 PMs ((sorry -long) about another mopar trans issue that's driving me nuts that has nothing to do with the OP's post and I didn't want to muddy up his thread.
 
According to the manual fluid change with torque converter is 8.5 quarts. Added to 8 quarts, fluid level is 1/2 way up the dipstick tube. Pump sprays fluid out of the cooler line at the radiator. Drops into gear both drive and reverse with a light thump, but won't move unless revved up quite a bit. Is there a possibility the torque converter isn't filling? That is the only thing I can think of that would cause the high fluid level
 
Freezerman said:
According to the manual fluid change with torque converter is 8.5 quarts. Added to 8 quarts, fluid level is 1/2 way up the dipstick tube. Pump sprays fluid out of the cooler line at the radiator. Drops into gear both drive and reverse with a light thump, but won't move unless revved up quite a bit. Is there a possibility the torque converter isn't filling? That is the only thing I can think of that would cause the high fluid level
Click to expand...
Not sure how long you have run it now.. but i would put it in neutral and let it idle for a few minutes... the pump doesn't pump or fill the converter in park..
 
This is the current transmission in the truck when I got it. I don't know if it is original

20210914_174859.jpg
 
I put a TF2 kit in the transmission worked great for awhile, started not wanting to move, fluid very high on dipstick. Tried new converter, no debris in pan. Hot, idling in neutral for 20 minutes, still overfull sprays fluid from cooling line.
 
Freezerman said:
According to the manual fluid change with torque converter is 8.5 quarts. Added to 8 quarts, fluid level is 1/2 way up the dipstick tube. Pump sprays fluid out of the cooler line at the radiator. Drops into gear both drive and reverse with a light thump, but won't move unless revved up quite a bit. Is there a possibility the torque converter isn't filling? That is the only thing I can think of that would cause the high fluid level
Click to expand...
Problem there is that unless it's a 70s trans with a drain plug in the converter you don't get anywhere near 8.some quarts out just by dropping the pan.
And yes if the drive lugs are sheared that would prevent the pump from filling up the converter. When you rev it high it will occasionally "catch" and slightly drag the inner pump rotor a little bit but nowhere near enough to generate any real pressure or volume.
I don't think I've ever put "8 quarts" into a 904. On a pan drop/fluid and filter swap it's more like 5, and on a fresh overhaul with a fresh empty converter it's more like 10. I don't know what manual you found that in.
And when you pull the trans and converter, even if you flip the converter over in a bucket you will not come anywhere near "emptying" the converter.
 
By the time the lockup converter came around Mopar eliminated the drain plug from the torque converter.
 
Remember, this a brand new converter so it is empty. I pulled the valve body and blew air in the feed port to the converter and got zero fluid from the return port. I pulled apart the body, found the shuttle for the port to the converter jammed. I think the stop arm had bent out and allowed the shuttle to travel too far. I will put it back together tomorrow and test

20230902_174056.jpg
 
Be sure to check the pressure regulator adjustment; TF-2s typically are set back against the retainer and unless the spring is just curved due to the retainer being bent and distorted, in this photo, it sort of looks like it is set pretty high.
 
Last edited:
I will double check the pressure setting before installing the body. Thanks
 
Duster346, thanks so much for pointing out the missing spring, I didn't get that installed. That is no doubt my problem
 
You must log in or register to reply here.
-

Back
Top