differences in 904's?

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Optik

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i am in the process of *helping* to rebuild my 904...a couple things, the rebuild kit that i got for it only had four clutches for the front drum, but the trans had five... and when we got the rear clutches/drum assembled, it was way too tight. i had to get .015" milled off the retainer ring, it seems to work fine.
so my roommate/tech guru said he was doing research and found that there is two or three different stock "stages" to the 904's. can anyone confirm this? mine supposedly came from a 77 fury wagon with a 360 2bbl so i guess it might have been a heavy-duty unit? would that explain the extra clutch needed in the front drum? maybe a tow package? the stock converter it had was real tight with a seemingly low stall speed (around 800rpm maybe?).

anyway, just looking for some of that old-skool interchange knowledge....

thanks!
-tim
 
Sounds like what was called an A998. The 5 disk front clutch was common with the V-8 versions back to the early 70's. If you have this, you have a good core. Later trannys (A999) also had a lower gearset which is worth looking for if you have access to later units (junkyards have lots of Jeep Cherokees). Order the extra parts to do the front drum right. Various ring and washer thicknesses are available to properly clearance various assemblies.

Stock stall speed for a 904 was in the 1400-1600 RPM range, low enough. If you couldn't brake-stall past 800 you had a problem.
 
The clutch pack snap ring is selective so is it possible you mixed up the front and rear clutch pack snap rings? The clutch discs are also a different thickness for the front and rear. The rears are thinner. Clearance on the rear clutch pack is spec'd at .032-.055 according to my factory service manual.

I've noticed most overhaul kits only come with 4 discs per clutch pack. I even got one once that only had 3 discs. Luckily NAPA still sold them individually so I was able to get it finished on time.
 
If the front drum had 5 clutches, its a A999. (usually behind 360's) 4 clutches is a A998. (usually behind 318's) Not all A999's had the low gear set. There is a number stamped on the drivers side of the case just above the pan rail. If its from a 1977 Fury wagon the number should be 4028465 if its a A999.
 
Oddly enough, the 904 in my 72 Swinger had the 5 disk front drum. I've saved this transmission as a core for that reason. I think it had been rebuilt in the past so the front drum may have been replaced as a service item. Looking for a low gear set for it and it'll get rebuilt and live again in my 65.
 
73Duster said:
If the front drum had 5 clutches, its a A999. (usually behind 360's) 4 clutches is a A998. (usually behind 318's) Not all A999's had the low gear set. There is a number stamped on the drivers side of the case just above the pan rail. If its from a 1977 Fury wagon the number should be 4028465 if its a A999.
Click to expand...

yes that is the number! thanks!!
-tim
 
73Duster said:
If the front drum had 5 clutches, its a A999. (usually behind 360's) 4 clutches is a A998. (usually behind 318's) Not all A999's had the low gear set. There is a number stamped on the drivers side of the case just above the pan rail. If its from a 1977 Fury wagon the number should be 4028465 if its a A999.
Click to expand...

so my next question is...will the 904 rebuild parts that i put in work allright? everything seemed to match up correctly as we are putting it back together...except for that rear drum retainer ring.
 
Optik said:
so my next question is...will the 904 rebuild parts that i put in work allright? everything seemed to match up correctly as we are putting it back together...except for that rear drum retainer ring.
Click to expand...

Shouldn't be any problem as long as everything was the same size and the seals were correct. I believe all the 904/998/999 trans. used the same clutch plates and steels and bands. The only difference sometimes is the seals. Some have different size lips. Make sure you pressure check each clutch pack before installation and then recheck them again after the complete assy. is installed and you'll save yourself alot of headaches. Same for the servo's. Air pressure check everything with 30-35 lbs. Here's a picture of which ports control what in case you don't have it.

727 Air test ports 2.jpg
 
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