here is a little history on the lift pumps and what changes were done to them and part Numbers. hope this helps
this is long. dont ask were it came from and i will not have to lie
CORRECTIVE ACTION SUMMARY
Below is a breif history of Lift Pump Part Number and associated
design/product changes:
12V 24V
3943467 3942802 Initial ISB Production
3944818 3942802 Added "saw cut" to the motor casing to better
detect leaks during production
3944508 Stainless Steel Valve Seat/Bronze Bushing for
the Internal Pressure Regulator
3945812 3945813 Some lift pumps were having a problem with
the internal wiring shorting to the magnet sleeve. The wiring
insulation was inadvertantly being
stripped from the wiring during assembly and during pump operation the
wires are shorting to the magnet sleeve.
Federal Mogul has changed the angularity of the wire lugs in the bottom
of the pump so the wires will enter behind the
magnet sleeve in a more direct manner, thereby reducing the chances of
stripping
the insulation. They also changed their end
of the line testing to look for this shorting problem during pump
operation. Federal Mogul is also adding a
radius to the top and the bottom of the magnet sleeve where the wires
travel behind the sleeve.
3948431 3948432 Corrosion of the connection of the pig tail
at the bottom of the pump was being seen. This was found to be to the
result of road salt acting as an electrolyte.
The electrical eye terminal was changed by the vendor from brass to
bronze. No corrosion is evident during similation
and salt fog tests with the bronze terminal. The mechanical properties
of the bronze meet or exceed that of the
brass and the vendor did conduct vibration test for further
verification. To further aid in corrosion
resistance, grease was added to each terminal at the Engine plant during
assembly.
3946151 3948070 The lift pump was updated with an
integral electrical connector. The integrated connector eliminates the
need for a pigtail type harness on the pump
and will eliminate the exposure of the pigtail to environmental elements.
Also updated was EMI reduction for the pump
due to an added capacitor to the internal circuit board and a Ferride bead
added to the connector.
3948431 (12V) and 3948432 (24V) where still
kept available for service because the wiring harness on older engines
where not long enough to plug into the integral adapter.
3938367 3938368 It was found the bearing material used
for the MFR. of bearings was not consistently uniform,leading to
variance in the pump performance. This
leads to change the bearing material to sintered iron from bronze.
There was also a change in armature shaft
geometry to straight one reduces the 100% inspection of the shafts.
These pumps have the integral connector.
For service, 3948431 (12V) was superceded to
3938435 (12V) and 3948434 (24V) was superceded to 3938436 (24V).
These pumps still maintain the pigtail wiring harness.
3990082 This is a service kit supercedes
3948431(12V). It includes 3938367 (12V) and a jumper harness (4025182) so
that it can be used on older engines with the
shorter lift pump connection wiring harness. 3938436 (24V) was superceded
to 3938368 (24V), but a kit was not created to
included the jumper harness, 4025182 must be ordered separately.
3990105 3990106 The lift pumps have been updated to include
hardened valve seat to reduce valve wear. The pump also reverts to a
prior use RFI circuit board due tocomponents being
detached and jamming the pump.
Service kit 3990082 was updated to include
3990105 (12V). 3938368 (24V) was superceded to 3990106 (24V), but a kit
was not created to included the jumper harness,
4025182 must be ordered separately.
III. IMPLEMENTATION SUMMARY
The supplier started building pumps with these corrective actions in the
first week of May 2001. The latest lift pumps, part number 3990105 and
3990106 when into production
Attention: TDR Forum Junkies 
