This is my posts from a thread about the lower ball joints on first gen Xterras with a SL on XF that might be helpful to some one here;
Both are the same. You have to ask for the part for a Frontier since Nissan sez you can?t change the ball joint on the LCA, you must buy the entire LCA.
The NAPA # for this part is NCP 2601596.
LINK HEREI did this last week with help from Dave from BANDIT4X4 so I know it fits
Ken, with your aftermarket SL it will not as hard as if you had OEM UCAs 'cause you can unbolt the upper ball joint from your aftermarket UCA (4 bolts?) and drop whole knuckle assembly from the front. The pain is making enough room to file or push in the 4 tabs on the top of the OEM ball joint (that lock the nut in place and are always positioned at the most award angles). Also you must make room to get a wrench on the ball joint nut and have room to swing a BFH at the top of the ball joint. Luckily I had Dave who did most of the work!
What we did;
Lift the truck and support with jack stands. Take off the wheel (duh). Use the jack to relieve some tension the torsion bar is putting on the LCA by lifting it so you won?t have to fight it later, we used a peace of 4x4 and the jack. Disconnect the TRE from the knuckle. Take off the front shock (you might be able to skip this and work around the shock but it's easy enough to remove so WTF). Take off the break caliper and secure it with zip ties (so as not to stretch the lines). Take off your hub and remove the C-clip that holds your half shaft in place. Unbolt the upper ball joint from your aftermarket UCA and push the UCA up out of the way holding on to the knuckle assembly so it doesn't flop around. When you unbolt the lower ball joint from the knuckle the whole thing should drop off unless I forgot something. I needed to change the half shaft so I took it off but I think you could just zip tie it out of the way (at this point it's only 6, 12 or 13mm bolts if you want to take it off). I used an impact hammer to push in the 4 tabs on top of the BJ 'cause I'm a lazy bastard, undid the nut (Dave had to hit the nut on one side with the impact hammer to get it started, if you do this don?t cut into the LCA) and smacked the top of the lower ball joint with a BFH a few times (impact hammer didn?t move it) to get it out.
We rented a ball joint press from AutoZone, $100 deposit, free rental. It seems silly to mention this to you but make sure there is no damage to the press before you leave AutoZone not only so you can get your $100 back but more importantly, so you don?t damage your LCA with their F'd up tool.
Make sure everything clean, rust free and rattle can the LCA before putting it all back together. Make sure everything stays centered as you press in the new ball joint. Dave didn't like the small channel that is left on top of the LCA between it and the new pressed in ball joint so he filled it with a bead silicone before putting on the nut. We used the impact hammer to create tabs on top of the new ball joint to lock the nut in place. Put it all back together, torque it all to spec. I'm driving it this week and will re-check the torque specs on it this weekend.
If it wasn't for Dave I would not have tackled this project but now that we've done it I think I could do it though it would have taken at least three times longer. Plus an extra set of hands will be an enormous benefit when you do it. Also air tools are a huge plus.