FNR5/5NR5 Secondary Valve Body Variations
We have had may folks asking about the FNR5/5NR5 transmission. We decided to write up a short article about this. Read below and feel free to comment below.
Complaint:
When it becomes necessary to replace the secondary valve body in an FNR5/5NR5 transmission, the replacement valve body appears differently than the original causing the tech to be hesitant with using it.
Cause:
There are presently three different secondary valve bodies in circulation for the FNR5/5NR5 transmission which can be quickly identified by the casting configuration around the accumulator piston area. Design A has a webbed type casting without any identification codes. Design B has a smooth casting with an identification code of FS50, while Design C is ribbed with a casting ID of 3V1Y.
Not knowing the reason for these differences causes the apprehension in swapping them out.
Changes:
There are presently three different secondary valve bodies in circulation for the FNR5/5NR5 transmission which can be quickly identified by the casting configuration around the accumulator piston area. Design A has a webbed type casting without any identification codes. Design B has a smooth casting with an identification code of FS50, while Design C is ribbed with a casting ID of 3V1Y.
Not knowing the reason for these differences causes the apprehension in swapping them out.
Correction:
As complete matched assemblies these secondary valve bodies can be interchanged without incident.
Interchangeability:
Individual parts (outer body, inner body and spacer plate) for A and B design assemblies can be interchanged within themselves. The slight changes made to the accumulator side of design body B allows for the same style spacer plate to be used in both assemblies. The valve body side of design A and B are the same even though the solenoid connector may be black with A and green with B (the solenoid is still the same).
None of the individual parts with design body assembly C can be interchanged with design bodies A and B. There are enough significant changes made between the two valve body halves and the spacer plate to make these parts non-interchangeable individually with parts used in A and B designed assemblies.
You can also find this article we’ve written here. We hope this helps!