Updating early 904 - is this a suitable donor?

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mtna_buzz

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Hey all, I need some help in identifying the donor trans I have. I've been though other posts - but haven't found a clear answer.

I'm in the process of going through a 904 out of my '66 dart. I want to update the input/pump to run a newer converter.

I picked up a newer trans at a wrecking yard as a donor - was already removed so I don't know what vehicle it came from. Number on the case is:pK4028483-5750-0576. Couldn't find it in the list linked in other posts here.

Pulled the pump/band/shaft/clutches - and it has 5-disc clutches in it. Comparing the parts - the 5-band internals are slightly longer when assembled.

Can anybody tell me what I have with the donor and if I can do a front swap - or if I should just rebuild the donor and run with it?

Thanks for any info!
 
Unless your doing a numbers matching restoration I'd just rebuild the donor trans. But remember a 66 trans. uses a torque converter with a smaller crankshaft register (1.53" o.d. vs. 1.81" o.d. for the later ones). so if your engine is a 66 you will run into a problem getting a torque converter that fits the trans. and engine.
 
The 273 is long gone, had a later 318 in it when I got it - with the small TC register against the later crank - with no spacer. I didn't know until I pulled it - didn't have any vibration issues....lucky I guess.

Think I'll run with the later trans - thanks for the reply!
 
You did get lucky it didn't vibrate or worse yet, trash everything. Staying with the later one is your best bet. That way you know there isn't something mis-matched in it. That might even be a low first gear unit which will give a little better acceleration.
 
Are you sure the JY one isn't a model "999". I have read about it. Almost same as 904 but w/ 5 disk clutch and lower 1st gear. It is rare and desirable. I understand it mates up fine, but some issues with the wiring for lock-up TC, etc. Does it have extra connectors? If you rebuild your 66 trans, I have read about swapping the input shaft to use a later TC.
 
BillGrissom said:
Are you sure the JY one isn't a model "999". I have read about it. Almost same as 904 but w/ 5 disk clutch and lower 1st gear. It is rare and desirable. I understand it mates up fine, but some issues with the wiring for lock-up TC, etc. Does it have extra connectors? If you rebuild your 66 trans, I have read about swapping the input shaft to use a later TC.
Click to expand...

There are no issues wiring the lockup converter because the lockup converter function is hydraulically operated, not electrically. Some models did have an unlock feature that was electric but that had nothing to do with it locking up.
 
Was lucky with no vibrations - the converter hub still looks like new.

I wondered about the 999 - but don't really know what the difference is - or when they phased them in. Not sure how I'd identify the lower 1st gear.

Got the one from the yard further apart and it all looks ok - except for the burnt clutches. It has 4-gear planetaries where the '66 had 3-gear. I think I'm just going to go through this one and call it good.

I don't think it's a lockup - have the converter with it and don't see anything out of the ordinary. I read that the 727's with lockup had the end of the input shaft machined smaller - don't know if the 904's had the same -but this one is splined right to the end.

Thanks for the replies - time to start cleaning parts!
 
mtna_buzz said:
Was lucky with no vibrations - the converter hub still looks like new.

I wondered about the 999 - but don't really know what the difference is - or when they phased them in. Not sure how I'd identify the lower 1st gear.

Got the one from the yard further apart and it all looks ok - except for the burnt clutches. It has 4-gear planetaries where the '66 had 3-gear. I think I'm just going to go through this one and call it good.

I don't think it's a lockup - have the converter with it and don't see anything out of the ordinary. I read that the 727's with lockup had the end of the input shaft machined smaller - don't know if the 904's had the same -but this one is splined right to the end.

Thanks for the replies - time to start cleaning parts!
Click to expand...

Sounds like you got lucky and got a non lock-up model as the input shaft splines are the way to tell. To tell the std. gear set from the low gear set look at the sun gear. If it is the same diameter on both ends it's a std. gear set. If it's smaller on one end it's the wide ratio set. I attached a picture of the exploded view of the gear train that shows the wide ratio sun gear. You can see how it's smaller on one end. I don't have a picture of the std. gear set handy but I can probably dig something up if you need it.
 
Just FYI that transmission was built on April 24,1977. I did not find that trans # anywhere either. I have heard there are trans #'s that exist but are not on the list.
 
Not all the 998s and 999s had the 5 disc direct drum. Some had 4. there's a seller on FeeBay that sells 5 disc direct drums LOADED with NEW clutches for 20 bucks and 12 bucks shippin. Just search 904 or 500 direct drum and it should come up. the A500 5 disc direct drum will interchange....in fact, you can almost dump the A518 guts into a 904.....almost. But not quite. lol The 5 disc direct drum is great insurance.

EDIT: I looked but could not find that FeeBay seller now. BUT, you can go here and get a reman SIX disc direct drum loaded for like 63 bucks.

https://www.wittrans.com/SchematicParts.aspx?Transmission=A500&LinkCode=555
 
Thanks for the info - I see the difference in the sun gear - didn't pay much attention when taking it apart so I'll check and see which I have.

Also good to know about th e mfg date - I figued it had to be '76 or '77 based on the chronological order of the list - nice to know for sure.

I'm also thinking about a reprogram kit (transgo) - this is a very mild street car so I don't want banging shifts. From the articles I've read the mildest stage just improves some overlap issues and removes some of the cushioning. Anybody have day to day experience with the kits? I'm going thru this with my dad - who was a chrsler dealer mechanic in the 60's...he's pretty skeptical of these kits.

Thanks again -
 
I have rebuilt numerous torqueflites over the past 29 yrs. and I can understand your dad's concerns regarding shift improver kits as many create more problems than they fix. In the early days I ran into problems using other brands of kits but the one truly reliable kit I have used are the trans-go kits. I never discovered them until 93 and since then I have never had a problem with one and they do exactly what they say so they are all I will use. If your looking for just a mild reprogram that will make the shifts a little firmer and make the trans last longer the TF-1 is the kit for you.
 
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