ReneeG
Lemhi pass from the west IS steeper than from the east. Normally it is doable in a automobile with caution and common sense. Remember this is a combination of private farm land/open range/NFS land and both sides of the pass are used daily by farm trucks during the summer (never seen a 18 wheeler though) However, IF there is greater than normal snow on the top, warmer than normal spring etc it could be rough going early in the spring due to the run off. But with the farm traffic I am sure that it is bladed quite often. We have have never had any trouble.
About 20 miles south of Salmon turn east off of ID #28 at Tendoy. About 10-12 miles to the top, the last couple of miles are the steepest, but with your dually you won’t have any trouble. At the top there is a picnic area/the “farthest most spring”/ continental divide information and numerous L&C information signs. From the top go east down to the village of Grant and go north about 10 miles to Bannack or from Grant continue east to Clark Canyon Reservoir, cross the dam to join I-15. Numerous L&C information Kiosks and information about a L&C campsite the is under the water of the Reservoir. Or from the top of Lemhi Pass go North paralleling the Continental Divide for a few miles then it drops off the ridge and turns west and joins ID #28 a few miles north of Tendoy.
Goggle: Lemhi Pass and all the links. Look up Lemhi pass on Goggle Maps.
Hopes this helps you out!
Richard