[Scrounge]

My driver is a 1984 D100 short bed with a 318 and a Torqueflite 904 automatic. Over the weekend, the transmission was occasionally straining to move the truck forward when starting from any uphill grade. When I returned home, I added a bit of gear oil to the rear end; it wasn't down much, and this did nothing to improve the trans performance.

I then changed the transmission fluid and replaced the screen. (I don't remember when I last did so, but this is the third time since buying the truck in 2006 with 89,000 miles showing. If original, it now has over 153,000 miles.) I have a shop manual for 1987 trucks, which shouldn't be much different from my model. It contains instructions for adjusting the kickdown and low-reverse bands. I was able to adjust the low-reverse band, and noticed afterward that shifting from first to second now occurs at or below 10 mph, when it previously didn't happen until around 15 mph.

However, I didn't adjust the kickdown band, as its location is difficult to reach, and I don't have the proper tools (wrench C-3380-A and adapter C-3705, according to the manual -- the wrench is a torque wrench that measures in inch-pounds rather than foot-pounds). The problem remains, though it's not consistent. After more driving, I noticed that, when coming to a stop, the trans will sometimes downshift below 10 mph. When this happens, the truck has no problems accelerating from a standing start. But when the trans doesn't downshift, it apparently starts from second gear, which may explain the slow initial acceleration.

I'll add that a thin layer of dirt was in the pan, which is probably normal, but no metal shavings were on the magnet (I cleaned both before replacing the pan). I also moved last month; I hauled a 6 x 12 foot trailer for a day, and made several more trips with a full bed.

So my questions are:

Where can I find the inch-pound torque wrench and the adapter that will work on the kickdown adjusting screw?

Will adjusting the kickdown band resolve the truck's problem? If not, what will?

Scrounge

 

[Bob Lincoln]

Most auto parts stores, and places like Sears, will carry an inch-lb torque wrench. I find Stanley to be a brand that has a good, consistent feel and click to the setting. I paid about $60, some cost far more.

http://www.sears.com/craftsman-micro-clicker-torque-wrench-3-8inch-drive/p-00931424000P?prdNo=2&blockNo=2&blockType=G2&PDP_REDIRECT=false&s_tnt=39869:4:0


The kickdown band takes an 8-sided 5/16' socket, which looks like a square with the corners radiused. It's available from NAPA as part number NB810 for under $8.

http://www.napaonline.com/Catalog/Result.aspx?Ntt%3dnb810%26Ntk%3dKeyword%26Nty%3d1%26Dn%3d0%26D%3dnb810%26Dk%3d1%26Dp%3d3%26N%3d0

If the band adjustment is too tight, I've found that it shifts hard and late. Too loose, and it slips.

A little gray clutch mud in the pan is normal.

You'll want to adjust the kickdown rod/linkage, too. If the rod is too long, it downshifts early and upshifts late; if the rod is too short, it downshifts late (requiring full throttle) and upshifts early. It's a sensitive adjustment with which a turn or two of the threaded rod can make a big difference.

 

[Scrounge]

Bob, thanks for the info. I should have guessed Sears, but I'm currently in a town that doesn't have one. I might have the socket with a 3/8 drive in my toolbox. I don't recall making a rod/linkage adjustment on the truck; if the band adjustment doesn't work, I'll see what the manual says about it.

Scrounge

 

[dana44]

Yeah, the socket is the one that is in all your socket sets you get new that has points in it, so they fit the square bolt without slipping. Usually the shifting problem when she starts out in second gear (from my experience), is a tiny bit of grit in the valve body that makes one of the shuttle valves stick. When my Barracuda did it, I simply did a couple downshifts at the stop light and manually shifted from first to second to third, not having to take the rpm up high at all, and it flushed the junk out. Not very common, but three or four times doing this fixed my problem.

 

[Bob Lincoln]

I have never found this socket in any socket set, and I've bought several 150+ sets. I don't think it's commonly supplied at all.

 

[ImperialCrown]

Not downshifting into 1st at a stop may be a sticking governor shuttle valve. Governor pressure should track with MPH. 1 psi per MPH.

 

[dana44]

I have never found this socket in any socket set, and I've bought several 150+ sets. I don't think it's commonly supplied at all.

You have to be kidding me Bob, there is a quarter inch and 5/16ths in almost every single large sets I have purchased in 40 years.

 

[Bob Lincoln]

Yes, there is. A six-point socket. The kickdown band screw requires an 8-point socket.

 

[dana44]

Yep, 8 points and the things look like 8 point stars. I have about a dozen of them, rarely used.

 

[Bob Lincoln]

Not Torx sockets. I'm talking about an 8-point socket for a square screw that has the corners radiused into an 8-point head. The 8 sides are not equal length - it's a square with small 45-degree angles cut off each corner. This socket doesn't come in any conventional kit.

it fits the square screw in the second picture down from the top:

http://www.dieseltruckresource.com/dev/adjust-your-bands-shift-points-and-line-t265745.html

The top picture shows the socket that is required - NAPA part number NB810.

 

[dana44]

The first picture is the 8 point socket and yes, I have several of them in several larger collection of socket sets, not torx screw sets, those are bought separate.

 

[Bob Lincoln]

I have never found a socket set that had any 8-point sockets; only 6 and 12. Regardless, the above info should help the OP.

 

[dana44]

Yeah.

 

[Scrounge]

The 8-point 5/16 socket is in my older toolbox -- I don't remember if it came with the Craftsman set, or if I found it elsewhere. I didn't have a chance to leave town; the local Wal-Mart stocks Stanley tools, but no torque wrenches. So I got as close to 72 inch-pounds (6 foot-pounds) as I could with the torque wrench I have. The kickdown adjustment screw was about 1/2 turn off; it only went in 2 turns before tightening, and the specifications call for it to be loosened 2 1/2 turns, which I did. When I drove it this morning, it shifted ok when cold, but warming up, it sometimes wanted to start from drive, and other times was fishing for first gear. I've not driven it far or fast, so maybe a longer test is necessary.

Thanks for the tip, Dana. I'll try shifting manually, but it may be from second, as my lever won't reach first gear. Nice '66, Crown. If it's the governor valve, will an additive work, or will I need to visit a trans shop?

I left the rod/linkage alone for now.

Scrounge

 

[dana44]

Well, if the shifter won't move down to first gear to start with, that needs to be adjusted properly. I don't like a lot of additives just because they are supposed to work without it. Like I said, the manually shifting helps move junk out of the shuttle valves because the line pressure forces the tiny bits of junk out and allow them to move freely. Adjust properly first, then see if it fixes the problem with a little more pressure before taking it to a shop, save the money right now.

 

[Scrounge]

If I pull shifter forward, it will go into a slot for first gear, but it won't stay there on its own. Where would this adjustment be made?

Scrounge

 

[dana44]

That would be the adjustment down on the arm on the transmission case itself, two rods go down there. One is the kickdown which goes towards the carb and mounted on the transmission and up to the carb, the other from the shifter at the steering column, that's the one that needs the adjustment. There should be a cotter pin and washer, then a square block and a pin sticking out of it and the rod the square block is on is threaded. put the trans/shifter in neutral and adjust for neutral position, should fix the problem for holding in first. If this doesn't work, which it should, other reason may be worn joint locations in the linkage preventing it from shifting all the way.

 

[Scrounge]

Some progress to report: I tried the manual shifting that Dana recommended. When holding the shifter as far down as I can in first, it acts like it's in second gear. After going to the store, then home (I'm only online at the library), I drove back here. I stopped twice on an uphill grade, and each time, it started from first like it should. It will need to do this every time before I'm convinced that the problem is solved, but so far, so good. I'll report again after some longer drives.

Dana, thanks for the shifter adjustment information. I'll attack it when I return home.

Scrounge

 

[Scrounge]

The Craftsman inch-pound torque wrench sells for about $70 plus tax at Sears, but they were out of stock. A Harbor Freight mailer advertised torque wrenches for $9.99 with a coupon, but no torque wrenches of any kind were on their racks.

After adjustment, proper downshifting remained sporadic, so I loosened the screw another quarter turn. That made it worse, so I tightened it half a turn, putting it a quarter turn from where I'd originally set it. Better, but still intermittent, and I don't detect a pattern. It will occasionally downshift on its own after I start accelerating. I drove the truck for more than 100 miles yesterday after the second adjustment. It often shifts properly, and I've shifted it manually enough, so whatever might be hindering the valves should be flushed, if that's the problem.

I don't see a cotter pin near the square piece surrounding the threaded linkage rod that comes from the shifter. A small bolt goes into the square from the top. Is this where the neutral adjustment should be made? If so, how? I'm not sure how much, if any, adjusting it needs; while the shifter has a little play, it remains within whatever gear it's in. But if it affects downshifting, per Bob's first post, then perhaps I should lengthen it a turn or so. It's currently upshifting earlier than it did, though I attributed that to the low/reverse band adjustment.

 

[Bob Lincoln]

Shift linkage misalignment won't affect downshifting. The downshift rod runs from the caburetor linkage to the transmission. The adjustment to the downshift rod is made underhood, several inches or so downstream from the carburetor. There should be a threaded rod to the carb, and you would pull a pin out of the barrel of a round pin, so that you can slide the downshift rod off the pin, rotate the carb end of it to lengthen or shorten it, slide it back onto the round pin, and secure it with the pin. The pin is similar to a short hair pin, like the other linkage pins usually found on carburetor linkage.

Newer trucks have a downshift *cable* from throttle body to transmission, but I don't think your vintage truck or the A-904 has that.