Ford Ranger 4x4 problems

I have a 2000 Ford Ranger 4X4, 3.0 V6. I recently replaced the engine with a Jasper rebuilt and now when engaging the 4X4 with the switch on the dash only my 4X4 high light will light up, no 4X4 low. The switch on the dash is working as tested by a mechanic. Vacuum lines were replaced as well. It is equipped with the vacuum pulse 4X4 system; however, I would like to bypass the vacuum system with manual locking hubs I found for sale here, My question is that even with the manual locking hubs, I do need to engage the transfer case with the switch on the dash, if I am only getting 4X4 high to light up, will the manual locking hubs function properly in 4-wheel? Or will I need to have both 4-high and 4-low available to have full 4X4 functionality? The mechanic that did my engine also mentioned that the problem could be with the JEM module. Just looking for suggestions on possible fixes so I can buy and use the manual locking hubs and avoid using the problematic vacuum system on this model. Thanks for any and all help. If I left any important details out please let me know, the 4X4 is important to me and my only concern with vehicle presently.

The only difference between low and high is the gear ratio being used in the xfer case. If you can deal with the low gearing, the 4x4 will work fine. I think there is a solenoid that engages low range on that truck, but low range is your normal regular gear ratio. So now that I think about it, with manual hubs I think low range will be Engaged as soon as you lock the hubs.

I would like to have the low range gearing work; however, it appears that only the high range is engaging with the switch on the dash. So my concern is that when I have the manual locking hubs that only my high range gearing will work. I want both low-range and high-range to work properly.

OHH I C, I misread your original post my bad… In any event there is an electrical solenoid that engages low. Make sure it is pluged in and that it is working correctly when power is applyed.

Yes, thank you. I can hear the electric engine (above the xfer case) click on when 4-high is engaged. When I put the switch to 4-low however, I get can hear no click from that motor nor will the light on the dash appear for 4-low. IF it were the electric motor on the xfer case that is the problem I would imagine that neither 4-high\4-low would work.

The high and low range is engaged my motor on the back of the transfer case. It easy to replace and test. Get the new hubs first. If the axel in the front is not moving sometimes the transfer case wont engage.

I believe the motor is working, because I can hear it click on when 4-high is engaged, only nothing when 4-low switch is turned. I did see that this is an easy replacement, only not sure why this would stop my 4-low light from not turning on the dash as it does in 4-high.


Still need help with this issue.