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Discussion Starter · #21 ·
Bob, thanks for the clarification and instructions. It will be a relief to work from the top instead of the bottom for a change.

On a side note, the '87 shop manual calls the automatics "Loadflite". Don't know if Chrysler changed the name at some point, or if truck transmissions are just named differently, similar to Commando, Magnum and TNT.
 

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I think Loadflite was a trade name for the A-727, the heavy duty automatic.

Forgot to mention that there will be a spring on that downshift rod near the carb, you have to unhook it to adjust, then reconnect when done. Go 1/2 turn at a time, the adjustment is sensitive to length.
 

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To adjust the shift location so you can drop it into first without having to hold it down, the two shift levers on the transmission, one will move freely and that is the kickdown. The other one is the shift linkage, which, place the column shifter in neutral, crawl under the truck and remove the gear selector connection (however it attaches), then take the shifter arm on the transmission and move it to park (you will hear a major click as the parking pall engages, then move it down to reverse, then neutral), then reattach the shifter rod so it goes in without any forcing or moving it, so the attachment is as neutral in attaching as possible, this will set the shifter arm to the transmission and all gears should engage properly at this point and you won't have to hold the shifter down to keep it in first.

Hopefully the guessing game of the kickdown band hasn't harmed it, slipping can cook them easily, whereas a shift kit installed can alter the adjustment by half a turn after installation, too tight is just as bad as too loose, which is why the inch pound torque wrench is really needed, even if you have to use it and return it the same day.
 

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Discussion Starter · #24 ·
My truck's throttle kickdown rod has no threads: the adjustment had to me made underneath. Wish I could find a photo or diagram online. The shop manual instructions are:

1) Perform transmission throttle rod adjustment while engine is at normal operating temperature otherwise make sure carburetor is not on fast idle cam.

2) Raise vehicle on hoist to make adjustment at transmission throttle lever.

3) Loosen adjustment swivel lock screw.

4) To insure proper adjustment, swivel must be free to slide along flat end of throttle rod so that preload spring action is not restricted. Disassemble and clean or repair parts to assure free action, if necessary.

5) Hold transmission lever firmly forward against its internal stop and tighten swivel lock screw to 100 in. lbs. (11 N-m).

6) The adjustment is finished and linkage backlash was automatically removed by the preload spring.

It didn't solve the problem. The engine was cold, but the fast idle cam was off. I don't have a hoist, but used a hydraulic jack. It didn't say where along the flat end the lock screw should be tightened; when I held the trans lever against the stop, the swivel slid off the rod. I pushed it tighter against the preload spring than where it was. I hope the swivel lock screw didn't need to be exactly 100 inch pounds -- I tightened it to about 10 foot pounds.

Bob's mentioned the return spring connecting the kickdown rod with the carb. It looks original, and doesn't feel as tense as it should, so I found a stronger spring of similar length at Napa (they didn't have the exact replacement, and I doubt that anyone has). It didn't help, either.

I wonder if I should go back underneath and spray some Liquid Wrench on the transmission lever.

Dana, thanks for the more specific shift linkage instructions. I'll try to make that adjustment when I go back underneath the truck.
 

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It seems like a step is missing in your adjustment. The slide bar rests against a pin/rod that sticks out of the throttle linkage, the spring attaches to it to keep the rod from coming off along with the throttle pedal cable, spring goes from a bracket forward on the engine to the pin. There should be another spring that keeps this rod and slot pulled forward so it rests or almost rests against the pin/rod. From there, the throttle should be opened all the way and blocked, which should be pushing against the slot which in turn pushes the linkage so the kickdown then increases the line pressure (the transmission kickdown arm) on the transmission. So, at this point, crawl under the vehicle, loosen the bolt and push the kickdown arm all the way forward and tighten. At full throttle, the line pressure will increase to the point it will kick down. This will give the basic adjustment and from there, knowing the direction she moves to increase the kickdown or reduce it, adjust in tiny, 1/16th of an inch increments. They can be a pain in the rear and are very sensitive, a 1/16th of an inch can mean 5-7mph difference in shift time, but don't think you are the first one this has happened to.

Now, if the adjustment doesn't work in this fashion, as in the adjustment in this manner makes the rod come off the end of the adjuster, time for the bolt and nut spacer on the back side inside the slide up on the carb. Have had to do this several times, will explain later if the above doesn't work.
 

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Discussion Starter · #26 ·
Since last posting, a neighbor loaned me his dial-in torque wrench that measures in foot-pounds. With it, I reset the kickdown adjustment, where I'll leave it, and attempted to reset the throttle rod swivel screw to where I originally found it. During another long drive yesterday, the truck wouldn't hit passing gear when I floored it. I don't recall that being a problem before, but I also don't recall the last time I used the passing gear. Never needed to in the city, and on longer trips, I normally use the cruise control. I don't know if this is part of the problem, or due to one of the adjustments I made.

Dana, I think you're describing the throttle rod near the carburetor. There are two springs coming from a bracket on the engine, one inside the other; they connect to the throttle on either side of the kickdown rod. I replaced those a few years ago, as the originals had lost tension. One them was between the washer and the throttle rod; I thought it might be rubbing against the rod, preventing it from fully returning, so I put the spring between the washer and the clip. That didn't help. I'll copy your instructions and try again.
 

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Missing kickdown is bad news!
This will quickly cook your tranny....
Try this way instead.
- Have some one floor the accelerator and hold ut there.
- Adjust the kickdown so the lever is at its end of momvement at the tranny.
This will make sure the tranny will kick, if not something is wrong and will need some fixing.
If the shiftpoints are wrong or the tranny shifts hard you can adjust the lenght (slacken it) but
make sure you retain kickdown function.
 

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Discussion Starter · #28 ·
I finally adjusted the shift linkage, and now the shifter will stay in first when I put it there. It wouldn't adjust properly in neutral, but the manual said to put it in park before tightening the little bolt, so that's what I did.

I reset the throttle linkage all the way in, and now the shift points are very close together, below 15 mph. It also slips a little from 2nd to drive. I'll back off 1/16" when I get home. Still no passing gear, but acceleration from about 55 mph is pretty strong.
 

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OK, so you are getting closer. No passing gear due to the shifting all three gears by 15mph, as you slowly adjust it the right direction it will start to work. At least you are working in the right direction now. Adjusting in neutral is the old means of getting the shifter to adjust, it may have changed over the years without my knowing it, but at least you figured it out.
 

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Discussion Starter · #30 ·
I bought a dial torque wrench at a different Harbor Freight, $9.99 with the coupon. They have them in inch-pounds, but only in the 1/4-inch drive. I bought the 3/8-inch drive, which starts at 5 foot-pounds.

I noticed a pattern: the truck sometimes stalls in hot weather, probably due to the ethanol in the gasoline (it has a 2-barrel Holley 2280 carb). So I occasionally put it in neutral when stopped at an intersection with a long stoplight. When I put it back into drive, it shifts from low on its own.
 

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Discussion Starter · #31 ·
Since last posting, I've adjusted the throttle linkage in two small increments, though I don't know if they're exactly 1/16 inch. It won't shift at all on its own unless I first leave it in neutral for a few seconds, but there's no more slipping from second to drive, which now occurs above 15 mph under normal acceleration. I've not driven it out of town, so don't know if passing gear has returned.
 

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On level ground with moderate acceleration, the 904 typically shifted 1-2 at about 12-16 mph and 2-3 at about 23-25 mph. Full throttle, 1-2 could be as late as 35-40 mph and 2-3 as late as 65-70 mph.

You do know that 'passing gear' is just a downshift from 3rd gear to 2nd, right?
 

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The need to prime the transmission hydraulics for a few seconds in neutral before starting out and the shift point drift may indicate internal hydraulic line pressure leakage due to worn clutches and hardened, leaky rubber seals.
A fresh clutch/seal replacement may be all that's needed to restore proper transmission operation here. A scatter-kit with ATF will probably supply all the needed parts and these 3-speed transmissions are fairly simple and easy to rebuild.
A pair of slide hammers is best to remove the front pump from the case and the front clutch may require a press for R&R a heavy return spring. Hand tools other than that. A shop tool rental business may be in your area if you DIY.
 

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Discussion Starter · #34 ·
Yes, passing gear is downshifting with the accelerator pedal instead of the shifter. The truck previously shifted out of first at about 15 mph and into drive at about 20 in city driving.

The seals may be leaking. Before changing the fluid and filter, I had to add fluid every few months, which I thought might be due to the pan gasket. It's since maintained its proper level, but it's been less than a month.

I've never rebuilt a transmission, and currently don't have the infrastructure to attempt it. I'd like to learn how, but preferably on a junkyard trans, not the one in the truck that performs fine in drive. I'll consult the manual when I return home to see what it takes.
 

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Believe it or not, an automatic is easier than a manual to rebuild, and Mopar trans of this vintage only go together one way. Snap ring pliers (inner and outer), feeler guages, a freezer (to shrink the clutch pack seals a little), and regular hand tools to do it. All you need is a flat bench and some patience, keep everything in order and get them together piece by piece, things like that. I found you can easily get the front pump off without slide hammers, I think they are 3/8ths diameter bolts, just need two long ones, like 4-5 inch ones, screw into the front of the case (two opposing holes are threaded), and use the claws of a hammer to hook on the bolt and use them to slide up the side of the bolt and catch the bolt head, move one to the other to slide the front pump out evenly. A leaking pan gasket it easy to fix, just dent each of the bolt holes outward on a piece of 2X4, use a bolt one size larger than the holes and give them a little pounding to bend the sheetmetal outward so the bolts suck the rails to the trans case instead of just at the bolt hole itself. Clean the valve body and check for scratches on the shuttle valves, 600 grit wet/dry to knock them down a tiny bit, lay the components out in exploded view to keep them in the proper order, some of them can be put in backwards. Use a shift kit to improve shifting and longevity, it will remove most of the check balls and improve the flow pressure to the valve body (thus clutch packs), Mopar Performance used ot have a kit with instructions and needed passage drill plate application for the extra fluid volume, about the size of a deck of cards and just as effective as the bigger kits from B&M and others for a whole lot less. As a matter of fact, it is so simple you can apply it to every transmission you rebuild, might have had one spring in it, but that could be left stock, it is the fluid pressure and check balls that is the important part anyway.
 

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Discussion Starter · #36 ·
I'm still in the process of adjusting the throttle rod linkage -- I don't drive the truck every day, but have driven it over 100 miles twice since last posting. Concerning blocking the accelerator pedal, I've been using a long screwdriver to hold the rod in its extreme open position before making the adjustment. I'm not sure how much farther I have to go to where it was originally -- I should probably have put some kind of mark on the spot. Anyway, no change to report in the kickdown's performance: the shift points are still too close together when it shifts on its own, sometimes doing so at around 10 mph if acceleration is slow, and it still doesn't have a passing gear. Manually shifting from second to drive between 15 and 20 mph eliminates any slippage, which takes the form of a higher rev that doesn't last a second. No problems in drive.

It may indeed be time for a rebuild, but I'm still hesitant to do so yet, as this is currently my only vehicle. And if I find a suitable used truck at a reasonable price, it may replace this one.

Dana's comment that it's easier to rebuild a Torqueflite than a manual might be accurate. I've rebuilt carburetors, and I'd much rather work on an AFB than a BBD (and either one than ANY Holley).
 

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Discussion Starter · #37 ·
After moving the throttle rod linkage a few more fractions, the shift points are now a little further apart. On a long drive yesterday, it actually kicked down without putting it into neutral first, but only once. No problems in drive at freeway speeds.

Also, before the engine is up to operating temperature, it doesn't kick down after I put it in neutral.
 

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Discussion Starter · #38 ·
After a few more throttle rod adjustments, the shift points are about 10 and 18 mph under normal acceleration. This seems right to me, so unless a compelling argument convinces me otherwise, I'll keep it there.

The transmission still won't shift back to first on its own after stopping. I'm either manually shifting into first, then immediately putting it in drive after starting to accelerate, or letting it idle in neutral after the engine is warm if the stop is longer.

The passing gear worked once, between 45 and 55 mph, but wouldn't engage at higher speeds.

Also, this transmission seems to have a hidden overdrive. It previously shifted between 35 and 40 mph, and stayed there during most of the throttle rod adjustments, but now it's shifting below 35 mph.
 

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Scrounge said:
The passing gear worked once, between 45 and 55 mph, but wouldn't engage at higher speeds.

Also, this transmission seems to have a hidden overdrive. It previously shifted between 35 and 40 mph, and stayed there during most of the throttle rod adjustments, but now it's shifting below 35 mph.
Passing gear kicking in higher is still a little more adjustment of the rod to meet higher governor speeds necessary to engage, you are going in the right direction for the natural shifting, kickdown will remain where it is unless the adjustment is set just a hair higher.

I am not sure what you are talking about with the hidden overdrive comment. Can you explain the shifting below 35mph.

As far as the kicking down into first from a stop, it is an indication there is either a piece of junk on the shuttle valve to first gear or a burr preventing the line pressure to normally move the fluid into the passages for first gear engagement at a stop.
 

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Scrounge said:
Also, this transmission seems to have a hidden overdrive. It previously shifted between 35 and 40 mph, and stayed there during most of the throttle rod adjustments, but now it's shifting below 35 mph.
Do we know if this vintage of 904 transmission has a lockup torque converter, when used in trucks? It was introduced in cars in the 1978 model year as a mechanical lockup. It would feel like another shift point after going into 3rd.
 
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