Straight swap

[captspillane]

The 151 and 150 four cylinders in Eagles both have different Chevy bolt patterns intergrated into the casting and are not compatible with a 6 cylinder. That's not wrong.

It seems that you're convinced you have a 904 and not a 998. You're wrong. If its the original transmission that came behind the 258 from the factory than its a 998. Only four cylinder Eagles had a 904 from the factory. There is a subtle bulge in the casing somewhere thats different, but most people including myself wouldn't be able to tell a 904 from a 998. When you buy a rebuild kit it will be the same for both, since its essentially just a single planetary gear inside that's bigger in the 998 than the 904.

Its not surprising that you couldn't find the correct torque converter for your transmission when you didn't know what transmission you had. All the 998s have a lockup torque converter. Most 904s did not but some did.

I did just put "1984 AMC Eagle" into the search engine at the Advanced Auto Parts website. It came up with a torque converter ready to ship for $95.79 and a $20 core charge. Under details it said its a 904 lockup torque converter with a "HS Lockup Decal" on it. You're not the only one who considers the 904 and 998 designation to be interchangeable. There is alot of sources out there that will call your transmission a 904 by mistake.

Instead of counting splines you need to just look at the shape of the shaft. Your lockup transmission has a smooth area without splines at the tip. This picture should clear that up:

[mudkicker715]

Its not surprising that you couldn't find the correct torque converter for your transmission when you didn't know what transmission you had. All the 998s have a lockup torque converter. Most 904s did not but some did.

Not true. 84 and older is cut off for lockup.versus 85 and newer non lockup