904 differences

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I do remember seeing them on some chevy's like the 700r4 and 200r4.
I didn't build many chevys as we had other builders for those.
My main job as a builder was BMW, Mercedes, Volvo, Allisons and stick shifts.
I was the only one in the shop that could do them, and the other guys did most of the Chevy, Ford and Chrysler stuff.
I used to do the domestics (as we called them) before that but I got certified in the exotics (as we called them) to make myself more desirable to higher end shops.
Being as all that was 25-30 years ago, I probably dont remember half of what I used to know.

Gettin old SUCKS.


oldkimmer said:
...............Almost every chevy tranny has seen that seal retainer..........kim........
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There were many updates and changes on the 904 style trans over the years. Some involve the size of the input shaft and number of seal rings. Also the size of the seal ring on the rear clutch drum that goes into the reaction shaft. The way the back of the reaction shaft was machined to accept the 5 disc clutch drum and the length of the splines on the rear clutch drum to engage the 5 disc front drum.

There were also changes made to the case for the suction side of the pump and of course the pump as well. But to answer your initial question the main difference between the pre 72 and the 72 and up transmissions was the rear seal size and the kickdown servo bore size.
 
Thanks Guitar that's is good to hear , I'm already planning to call the dealer for the correct rear seal with the dust boot and I didn't mess with the servo .I should also add I'm going to see if I can find a seal retainer as well ,thanks again guys .
 
there are sealing rings inside the servo that should be replaced if you have the trans apart...
 
70aarcuda said:
there are sealing rings inside the servo that should be replaced if you have the trans apart...
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I'll check the video I have to see what that entails , the trans has been back together for a while , this thread was to gauge whether there was a need to open it back up , there was nothing wrong with the tranny when it came out I was just conned by the guy doing the resto work into the common falsehood that I had to switch to a 727 if I was going to put more power under the hood ,he owned a small chain of tranny shops before he retired and built the crappy 727 he sold me himself , it started bleeding and slipping and shifting funny during my trip cross Canada last year so I ordered the rebuild kit for the 904 to upgrade the front drum and clutch pack while the car was coming home on the train and went for it , work has kept me busy 6 days a week so I haven't had the energy/time to get the swap done but I now have a slight lull in the action and am only working 5 days a week for the next couple of weeks and need to get this done and setup for this years trip to Moparfest -still hoping to find time to side trip to see the icebergs in St Johns harbour in NFLD on the way to New Hamburg
 
Alright this thread is now evolving into my first "tranny swap " the 904 is painted and almost ready to go in I still need to talk to the dealership Monday about a rear seal with a dust boot and front seal retainer.I also need to ask you guys if there's an easy way to pop the front seal from the outside without messing up the bushing behind it ? a special puller maybe ? other than that I found the lines for it and cleaned them up since 1 of the 727 lines looks iffy where it attaches to the rad , also found the dipstick and tube and got them spruced up as well .
I pulled the drive shaft and started pulling bolts but got stymied by the upper starter bolt I think i may have to unbolt the header on that side to get it out of the way a little but I got hungry and called it a day .
What should I be expecting when I get to the cross member I can't find one for the 904 in my parts bin which leads me to believe the guy who put the 727 in reused the same cross member or he threw the 904 one away ,i seem to remember talk of an adapter plate of some sort being available but I don't remember if it was for this sort of swap .
What is the deal with all the different flex plates ? I'm going to get a price from the dealership on a mopar one for a six bolt crank with 7/16 converter bolts but I've seen prices from $15 to $120 on these things what is up with that are some of them made of Latinum or something ?
well thats it for now folks I'll update tomorrow after I get that darn starter bolt out and wiggle this darn boat anchor of a tranny out from between the H pipe .

PS It seems it might be just in time for this swap as when I unbolted the flex plate I spun the converter a couple of times and first it gurgled and made a rubbing sound as I turned it then about 30 seconds after I had stopped it made a clunkity clunk clunk clunk sound like something metal bouncing down between other metal or several metal things dropping in succession since it happened after I had stopped and was doing something else I'm not positive if it was from the converter or the trans itself but whatever it was I'm sure it wasn't good eh ! LOL
 
Sears sells a seal puller for yanking seals but if your careful you can use a large straight blade screwdriver. Just stick it in behind the seal at an angle and pop it out. Done it may times that way myself. If you have a wobble extension you might try that with a shallow socket on the top starter bolt. That's what I use on mine that works. I thought there were only 2 flexplates for LA small blocks. Dealers are notoriously expensive for parts. May want to check Summit or JEGS or E-bay. Or put a want ad here. Are you using a converter with 7/16" bolts? Factory size and most aftermarket converters use 5/16" bolts. When you step up into more higher perf. converters you see the 7/16" bolts.
 
thanks fishy I was a little nervous about trying the screwdriver but if that's the way then that's the way eh lol , Summit has 7 or 8 different listings of flexplates for a 10" pattern ,internal balance, six bolt crank , with 7/16 bolts ranging in price as i said above ,my local speed shop quoted me $22 which leads me to wonder if the kid read the wrong part #, yes I upgraded the converter to a 10" race unit to handle the stroker and it uses the bigger bolts which is why I can't reuse the plate I have .
I used the wobble to do it last time with enough extensions to reach the front side of the K member lol to get that one bolt , I like to wrap the wobble and the socket etc.. in a couple of wraps of masking tape ,it stops it from flopping , keeps the socket on it and still bends when it has to .
 
cannucky said:
thanks fishy I was a little nervous about trying the screwdriver but if that's the way then that's the way eh lol , Summit has 7 or 8 different listings of flexplates for a 10" pattern ,internal balance, six bolt crank , with 7/16 bolts ranging in price as i said above ,my local speed shop quoted me $22 which leads me to wonder if the kid read the wrong part #, yes I upgraded the converter to a 10" race unit to handle the stroker and it uses the bigger bolts which is why I can't reuse the plate I have .
I used the wobble to do it last time with enough extensions to reach the front side of the K member lol to get that one bolt , I like to wrap the wobble and the socket etc.. in a couple of wraps of masking tape ,it stops it from flopping , keeps the socket on it and still bends when it has to .
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Your local speed shop might have quoted you a stock flexplate, or some Chinese cheapie. Been a while since I looked for one on Summit's site so I had no idea they had so many. Yeah I usually wrap a wobble U-joint with tape too cause most of the time their loose and floppy. When I said wobble I was referring to a wobble extension, not the u-joint type wobble. The wobble extensions don't flop around as much as a u-joint type. Their a little limited to how much range they have but it's plenty to do most things. If your not familiar with them type in wobble extension on E-bay and I'm sure a ton of them will pop up. I bought a cheap set off E-bay yrs. ago when I first saw them and they actually work real good.
 
You can drill the converter bolt holes in your flexplate to fit the 7/16 bolt size. The flex plates aren't any different except for the size of the hole unless you want an SFI certified plate.
 
...........tranny crossmembers r the same........if the converter made that noise i would take it back out and give it a shake, maybe theres something wrong inside....kim....
 
thanks for the info fishy I'll ask my go to parts guy about one of those wobble extensions when I get him to quote me on a flex plate as well , his shop is closed on sunday so I called the bigshots at Lordco lol . My other guy always gives me the best price he can and try's to send me to other stores if he knows they can do better but I prefer to pay a small premium to keep him around , honest knowledgable guys are hard to come by these days .

Good Idea Guitar I don't have a drill press but I'm sure I can get one of my sub -contracters who does to do it for me for nothing if I can't find one at a decent price , I'm trying to build a complete spare drive train out of what I swap out .

Yeah Kimmer that ones coming out for sure , it's the old one that goes with the 727 and was coming out with it anyway but it is just lucky something bad didn't happen since I've been burning around in it on weekends lol and I don't baby it ever it sees a lot of time in 2 around town , no sense letting it shift at 45k when 50s the speed limit eh ! haha
 
Just called my local dealer he can't find the rear seal or the front seal retainer with out part numbers so any body know the numbers doh !
 
...............That front retainer is for chevys.......cant help u with the reareal as i hardly ever build a 904, do they have 1 4 a 998 or 999..............kim.........
 
Do you have a NAPA to try for the rear seal? I got an original type there about 2 yrs. ago. Not sure if they still have them but it's worth a try.
 
thanks guys , I'll try calling NAPA but I'm not holding my breath on them , the last time I walked in there the pretty blond girl didn't have a clue what I was asking for or how to type what I was asking for into the search function in her computer LOL but damn she looked fine if your buying off the shelf she's your girl , thats why I have a go to guy at another store who is a car guy and has been since the early seventies .he'll know about the chevy retainer but probably won't be able to see if the seal he can get has the boot or not .
 
It's not just gals that don't know squat about finding parts. In my area there's usually only 1 or 2 people that know (or care) what their doing. Most auto supply stores in my area have kids fresh out of high school that never even heard of a Plymouth.
 
fishy68 said:
It's not just gals that don't know squat about finding parts. In my area there's usually only 1 or 2 people that know (or care) what their doing. Most auto supply stores in my area have kids fresh out of high school that never even heard of a Plymouth.
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Touche ! my friend the guy at Lordco didn't seem to know how to operate his computer either when I called them , couldn't get my hands on a wobble extension but after a couple of hours of cursing under the car I stuck a ratcheting box wrench in from above and eureka out it came , took about another 1/2 hour of contortionist maneuvers but the rest of the bell housing bolts are out as well along with disconnecting the lines and wires ,just the speedo cable and the cross member left to undo and down she comes .
 
How about calling TCS Products in Langley to see if they have what you need or advice.
I am going to get them to build my TQ converter and they are well thought of.
 
Scamper said:
How about calling TCS Products in Langley to see if they have what you need or advice.
I am going to get them to build my TQ converter and they are well thought of.
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If you go back and read the thread you will find that they are the folks I bought all my parts and converter from in the first place , they were also very helpful on the phone when I was doing the work , they are indeed first class folks there ,We also have some of the best Mopar techs in the world right here on FABO and since TCS is a business I prefer not to tie up their phone line pumping them for free advice that they would gladly give when I can get top flight advice and help here from guys who are giving it in their spare time as part of the hobby , THANKS ALWAYS to all of you who do this selflessly for those of us who are learning to do it for ourselves -Chris
 
I was reading in another 904 thread that there seems to be some difference in band adjust based on the lever being used , how do I tell which lever it is , I went by the FSM which stated 3 1/2 turns for the 6cyl and 4 turns for the 318 so I went with 4 . now after seeing the discussion I am second guessing myself on that LOL I really don't want to pull this thing back out after it goes in , and after redoing the front and rear seals as a just in case precaution I am mentally going through the other things I changed too . please advise me as to how to identify which lever I have and what adjustment you recommend
 
.............the lever has a # on it, usually 2.9,3.2, 3.8, 4.2, 5.0..if u put in a rmvb u need the 5.0 band adj 2 1.5 turns...rear band is adjusted by being single or double wrap...a double wrap looks like 3 pieces put together...kim.....
 
cannucky said:
I was reading in another 904 thread that there seems to be some difference in band adjust based on the lever being used , how do I tell which lever it is , I went by the FSM which stated 3 1/2 turns for the 6cyl and 4 turns for the 318 so I went with 4 . now after seeing the discussion I am second guessing myself on that LOL I really don't want to pull this thing back out after it goes in , and after redoing the front and rear seals as a just in case precaution I am mentally going through the other things I changed too . please advise me as to how to identify which lever I have and what adjustment you recommend
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The adjustment you quoted (what I highlighted) is for the rear band which doesn't have a changeable lever and those figures are if it's a double wrap band which Kim explained. The front band is the one with the lever that can be a different ratio and as Kim said it's stamped on the side of it as to what it is and what ratio it is determines the adjustment.
 
thanks fishy whats the adjustment for a single wrap ? just for the sake of knowing . I'll be using this thread as a reference for any later work or the next time I do one of these .
 
I always stuck my fingertip between the servo pin and the lever, then tighten the adjustment till it started to hurt and lock er down. (really)


Two turns out from 65 lbs is recommended adjustment.
1.5 to cure a slight flare.

cannucky said:
thanks fishy whats the adjustment for a single wrap ? just for the sake of knowing . I'll be using this thread as a reference for any later work or the next time I do one of these .
Click to expand...
 
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