Probabally around $2,000 or so. You need a complete D44 with the "batwing" (its the cover and support for the diff) the D36 has one less cover bolt and the two are NOT interchangeable. You will also need a C-Beam and driveshaft from a manual car (the auto's have longer pieces). The driveshaft yoke from your auto will have to be swapped with the yoke from the manual driveshaft, also it would be very wise to have the driveshaft rebalanced afterwards. This would also be a good time to replace all affected U-joints ... there are six.