truck sways on highway

[blazer4x4]

have a 1999 blazer 4 door 4x4 when i get up to highway speed about 60 mph it sways. could it be cause the back tires are brand new and the front tires are pretty worn. I tried to get an alignment done a few months ago but they said they couldnt do it cause there was too much play in the pitman arm. Could that have something to do with the swaying?

[MT-2500]

Yes it could.
But also check the other front end parts and replace all loose one .
And the get it lined up.
MT

[2percent]

and you migth want to check your stabilizer pins mine did that because they were busted when I bought my truck

[old_master]

You might have trouble with the 4WD if there is too much difference in circumferance between front and rear tires. Very important on 4WD vehicles to have all four tires the same size, same brand even better, Tire pressure needs to be the same on all 4 also.