differntial problems suspension problems

[nas517]

I bought my wife a 2005 X5 4.8is for Christmas. She hasnt seen it yet and I need to get it finshed by tonight. I took it in to the dealer yesterday becuase the suspension was leaning on the passenger side. Both front and rear wheels was down about 3 inches. They diganosed it and told me it seems to be the Ride height control module. I told them to clear it out and I will pick it up. They wanted 1500 dollars and to keep it for 2 weeks until the control module came in. I call a neigboring city (Cincinnati) and they had a ride height control module in stock for $650 dollars. Don Jacobs In Lexington (my city) wanted 1000 for the part and 500 for labor. My question is. when i picked it up, the inside button to adjust the height on the suspension is working now. Before it wasnt and the green light went away. Now it working. The X5 leveled itself out. It looks a little better but I think its supposed to sit a little higher. It has 22 inch staggered wheels on it so im not sure if it supposed to be that low. I have a control module that belongs to a 04 Range rover with the same compresosr and suspension. Does anyone know if I hook that one up will it work? It looks the same. Also does anyone have any trick to put a front differntial in, I took the old one out and it was really hard to get out but now I have been trying to get the new one back in and It dosent want to go back in. Any trick. Ive un hooked the motor mounts and dropped the sub fram a little. Anyone help please.....