4R70W torque converter code

[turbotim2]

I am looking for the stamped code on the original TC for this 4R70W I picked up. Can not seem to locate it, any ideas? Thanks!

 

[rocknhorse76]

51A, 61A, 65A, 69A

If you’re looking for a stock spec reman unit, go with an FM69C

 

[spap]

What were the differneces. does anybody know. just curious

 

[turbotim2]

The differences I have seen are stall, diameter and bolt pattern.

 

[turbotim2]

The differences I have seen are stall, diameter and bolt pattern. Also seems to be different shaft spline counts.

 

[Broncobowsher]

The differences I have seen are stall, diameter and bolt pattern.

It's been 20 years since I did the research. But I recall of the stock offerings there were 3 versions that work on the small block, You could tell the difference by looking at the turbine vane angles embossed in the shell. One was a right hand twist, another a left hand twist, third was straight. The stock Explorer was the good one. I left it at that.

If you really want to get into the proper engineering of a convertor the term that actual engineers use is the K-factor. It is a term rarely found outside of SAE white papers.

 

[turbotim2]

I am not looking to get too technical but the parts stores seem to list 3 when looking specifically at (in my case) a 99 Mercury Mountaineer.

 

[rocknhorse76]

These are most likely the 3 choices you have. Go with one of the high stall options. The first one listed supposedly has a heavy duty clutch, and is the one I used when my transmission was stock and I had a mild EFI 351W. Oh, and my 4R70W originally came from a 99 AWD Mountaineer.

 

[Broncobowsher]

These are most likely the 3 choices you have. Go with one of the high stall options. The first one listed supposedly has a heavy duty clutch, and is the one I used when my transmission was stock and I had a mild EFI 351W. Oh, and my 4R70W originally came from a 99 AWD Mountaineer.

Straight and angled ribs, matches my memory as well.
High stall is fine. Still pulls well at idle. You can get away with high stall since there is a convertor lockup to bypass the stall at cruise.

 

[turbotim2]

Thanks!

 

[spap]

Thanks I used the stock one about 10 years ago, diff bolt pattern for modular motor maybe , didn’t want to get to deep just never heard of different one s