904 witchcraft

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Scott Warner

Scott Warner

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Joined
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Location
North West Phoenix
I bought this car 5 years ago with a fresh rebuild on the 904. It layed dormant till recently. It had been driven through all the gears...around the block a few times in the last few months...i did a cam swap...did the break in...round the block a few more times....back to the garage for a few weeks...new heads, headers, exhaust all done in chassis...i never separated engine from trans. Now i have no gears. This was literally a perfectly functional unit. I disconnected the shift linkage at the trans and have a positive detent for each gear. Today im going to yank a cooler line to see if i have pump pressure. Yes the fluid has been checked..and added an extra pint for good measure...properly (not my first rodeo). If its not the pump....im thinking ive got to drop it out and tear it down..if it is the pump...ive got to yank it out and tear it down. But im just throwing this up for open discussion incase i maybe forgot to check something. Any ideas gents?

Thanks
 
Scott Warner said:
I bought this car 5 years ago with a fresh rebuild on the 904. It layed dormant till recently. It had been driven through all the gears...around the block a few times in the last few months...i did a cam swap...did the break in...round the block a few more times....back to the garage for a few weeks...new heads, headers, exhaust all done in chassis...i never separated engine from trans. Now i have no gears. This was literally a perfectly functional unit. I disconnected the shift linkage at the trans and have a positive detent for each gear. Today im going to yank a cooler line to see if i have pump pressure. Yes the fluid has been checked..and added an extra pint for good measure...properly (not my first rodeo). If its not the pump....im thinking ive got to drop it out and tear it down..if it is the pump...ive got to yank it out and tear it down. But im just throwing this up for open discussion incase i maybe forgot to check something. Any ideas gents?

Thanks
Click to expand...
Is the throttle pressure linkage hooked up to the carburetor properly? And was it when you were driving it before?...
 
Yes...was adjusted properly when i bought the car and i swapped it to a cable assembly about a year ago..and verified it was still in adjustment prior to starting it after this round of parts swapping.
 
Yes the fluid has been checked..and added an extra pint for good measure...properly (not my first rodeo).

As previously stated
 
UPDATE:
I yanked the forward cooler line at the cooler..fired it up in neutral....barely a trickle. So just to put all the nails in the coffin, im going to disconnect and blow through both lines to ensure they arent blocked. Shoot some brake clean through the cooler...if that is as uneventful as i expect...ill drop the pan and check the filter...as that will be the final nail in the pumps coffin.
Any other ideas...keep em coming
 
You separated engine from trans. Did the converter reengage with the pump (twice) before you bolted it all back together or did you do the bad thing and draw the pieces together by tightening bolts? Did you bother to put the converter bolts back in? I no not your first rodeo but it might be the first time for your error.
 
He said when he did this last round of work that he did NOT disconnect the engine from the transmission.
 
What you see at the cooler-line, is coming from the TC and dumping into the pan. At idle, in Park, you might have as little as 5psi in that circuit. The max is likely to be no more than 30 psi@1600rpm, in reverse.
You can check your pump by measuring the pressure in the L/R servo in reverse gear. IIRC, you'll be looking for over 230psi at 1600rpm

Unless you have a full manual VB, your trans always starts in first gear. If you put it into low, then the power goes thru the L/R band. If in second or drive, then thru the sprag.
In both cases the hi-drum also is engaged.
It is highly unlikely for the pump to fail catastrophically.
It is highly unlikely for BOTH the band and the sprag to simultaneously fail.
It is more likely that the hi-drum lipseal failed.
It is MOST likely that the manual valve is not properely detented, but you said you checked that.

That's the best I got.
unless Line-pressure is hemorrhaging somewhere else. And the most likely places are ; the governor, the accumulator, and the aforementioned manual valve.
Good luck
 
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AJ/FormS said:
Only a fraction of the oil goes to the cooler.
You can check your pump by measuring the pressure in the L/R servo in reverse gear. IIRC, you'll be looking for over 230psi at 1200rpm
Click to expand...

The only a fluid pressure gauge with that scale in my posession is an A/C manifold...and im not cannibalizing it...a decent fluid pressure set up is a few hundred off the tool truck. And i cant justify it right now (still on medical leave at half pay)
 
AJ...
The detents are firm and positive. Is there a possibility of a gummed-up or bent manual valve even though all detents are present?
Additional info...any position except park...the wheels rotate...park is still functioning and locks the wheels...and this is an oe valvebody...not even a shift kit...although i do have a new TF2 in a box on the shelf.
 
Scott Warner said:
Now i have no gears. This was literally a perfectly functional unit.
Click to expand...
Scott Warner said:
Additional info...any position except park...the wheels rotate.
Click to expand...


I'm confused;
the wheels rotate in gear,
but you have no gears.
And park locks the driveshaft.

But the clincher is this
Scott Warner said:
.any position except park...the wheels rotate.
Click to expand...

IDK what's going on. There are lots of smarter than me guys here on FABO, hopefully some of them will check in soon; give the thread a couple of days to play out before you drop the trans.

No the manual valve, should be all right.
Maybe the filter is plugged.I'm just guessing now.
 
All i am trying to clarify is that it "seems" the detents are all there...and that engine off...rear end off the ground:
1. In park the wheels are locked
2. In R,N,D,2,1 the wheels can be manually moved by hand.
Just to say it doesnt seem like a linkage issue
 
Oh, I thought with the engine idling and on jackstands
then moving the shifter; silly me.,lol.
Knowing this now, still don't make me any smarter tho,lol.
And that more or less rules out the plugged filter idea.
Without fluid pressure, the only thing your test proves is that the parkrod is moving and therefore, so is the manual valve.
If the sprag is ok, it will make a very quiet screeching sound in the easyturning direction and none in the other.
 
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With the rear off the ground, engine running, there is no shift position that causes any reaction to the driveshaft and hence also the wheels. Maybe ill splurge and pickup a gauge...would 500 psi be high enough for tranny work? I do have a BB 727 to do in the future.

And sorry for the confusion...i sometimes type how i would talk...and some little details get lost in translation
 
All the rodeos I've been to I was always told to not overfill the transmission. You put it in neutral with the engine idling and you check the level.
 
May have broken off the pump drive hub on the torque converter. If no fluid is pumping from cooler lines when running, your pump is likely not turning.
If this is the cause it was nothing you did wrong and was likely a stock or stock replacement converter. The hub is not very strong on the stock converters.
 
Scott Warner said:
would 500 psi be high enough for tranny work? I do have a BB 727 to do in the future.
Click to expand...

Too much, actually. The max you need is 300, and only for one test.

There are 1/8" pipe plugs all over the Torqueflite. A good FSM or book is a must.

You can get most stuff at a hardware store affordable - some 1/8" mpt x hose barb fittings. Or 1/8' mpt x whatever hose standard you prefer. If you have some old 1/4" flare refrig hoses that are to old for refrig, they're great for making stuff like this. The gauge - the bigger the face, the better. 3" face would be the min for me, 4" is better. A 1/8" coupling and a 1/4" fl x 1/8" fitting and you're in business. The most expensive part is the gauge. The factory tests like to have two connected at different spots for comparison.

0-100 psi 4" face pressure gauge - Google Shopping
 
Scott Warner said:
UPDATE:
I yanked the forward cooler line at the cooler..fired it up in neutral....barely a trickle. So just to put all the nails in the coffin, im going to disconnect and blow through both lines to ensure they arent blocked. Shoot some brake clean through the cooler...if that is as uneventful as i expect...ill drop the pan and check the filter...as that will be the final nail in the pumps coffin.
Any other ideas...keep em coming
Click to expand...
u
either the converter slid forward and disengaged the pump or the pump sheared the engagement tabs.....

One thing I always do once the converter is seated....move it back n forth and you can hear the converter hub clack again the pump drive...
 
I have not had the engine or tranny out of this car ever. The PO had it rebuilt a few months prior to my purchacing this car. When i bought it..it was a running driving car. It sat for 4 years in my house in Az. It drove out of that garage and onto a transport trailer for the trip to Houston. It drove off the trailer and into my garage here. Was taken around the block a few times in the previous 12 months. I swapped the cam....drove it around the block a few times on several different occasions. It was in the garage for 6 weeks before i pulled the heads and swapped in the rebuilt ones with a set of headers and a new exhaust kit.

As previously stated..... the engine and tranny were not seperated since the tranny was rebuilt prior to my acquisition of the vehicle.
 
pishta said:
"5 years, 50,000 miles...whichever comes first"! Sorry, had to toss that in there. Can you check line pressure from the test port?
Click to expand...
Ill get back around to checking the fluid pressure some time next week.

As it is now my HOA is having fits because i brought home a boat that was supposed to be replacing the Coronet in the end garage (only one the boat fits in) for some stringer repair. But with the Coronet not mobile...thats on hold...i guess i need to find a temporary storage facility...when it rains it pours.
 
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