Need to ID a Transmission

[Cuprum-74]

Hey folks,

I was able to identify the trans I have in my Duster,

It is a: #4028877 - 1978' 318/A904 (standard without lockup)

Unfortunately I only have info between 1969-79

I found a A904 series tranny in a salvage yard it was already pulled out and stuffed in the back of late 80's work van. The serial number on it is #4505170
I tried looking up the serial number and only found one a brief description on one website.

#4505170 1989 Diplomat' A999 Lock-up, some 3.9 ltr vans/trucks.

I do not know how accurate that is but I need to know if this is something worth haulin' away and would be an easy pick as it is just laying there... mocking me.

 

[fishy68]

No idea what the 4051570 is for sure but if your sure it's a A999 it's worth grabbing (if you can get it cheap enough) as they are a heavier duty trans. with a low gear set.

 

[Bulldozer]

the a999 is a lock-up i think you need the converter

 

[Cuprum-74]

Well the salvage yard wanted $125 plus $25 core, so a total of $144 after tax and military discount. So I went ahead with my gut feeling and got it today.
One website noted:
4505170 - ‘89Chrysler,Diplomat&PlymouthPass.,A999

The full number is PK4505170 9937 9574

I was told the second number is a 10,000 day calender so I decoded it at October 11, 1988, by using this website: http://maxwedge.com/articles/10k.php
Pretty much spot on. So I'm tearing into right now.

 

[fishy68]

Since there is some mystery of exactly how many friction clutches in each clutch pack on an A999 please post how many it has. Also post if it has the low gear set it is reported to have. If you don't know how to tell look at the sun gear. If it has the same amount of teeth on each end it's not a low gear set. If it has more teeth on one side it has the low gear set. I attached a PDF file showing a 904/998/999 gear train with the low gear set. The sun gear is right in the middle and as you'll see it has more teeth on one end than the other. Thanks

 

[Cuprum-74]

Well the verdict is in:

It has 4 planetary gears

4 Front clutch discs maybe?

Well its definitely a wide ratio the teeth is maybe 38:28(?) unless I counted wrong.

 

[fishy68]

Great! Tnx for the info... Yes that's a 4 disc clutch carrier. Looks like you scored

Is it a lockup trans?

 

[Cuprum-74]

Great! Tnx for the info... Yes that's a 4 disc clutch carrier. Looks like you scored

Is it a lockup trans?

Yes it is, unfortunately no torque converter came with it, I believe it is hyd. controlled as I see no wires.

It definitively needs a rebuild the thing reeks of burnt phenolic, everything else looks solid though.

 

[fishy68]

I thought it might be as that's all I've seen although I have read they made some that weren't lockups. All the 904/998/999 lockup units were completely hydraulic controlled. If you so desire I believe you can convert it to a non-lockup by just swapping the input shaft and valve body from one that wasn't a lockup. Only thing is you have to get a input shaft (or complete rear clutch assy) from one of the same vintage so it mates up to the oil pump and front clutch pack properly, or replace the entire front end with non-lockup parts.

Good deal on it only needing a rebuild. Rebuild kits are cheap, it's the hard parts that add up fast. If you ever do need any hard parts www.wittrans.com is a used transmission parts supplier and their cheap and reliable.