yesterday I was driving on a flat road at about 45mph with my 85 Toyota 4x4 pickup and it started to slow down and when I pressed the gas it just kept going slower then when I came to a stop it completely died and when we checked under the hood it was not smoking and we checked all the fluids and they were all full and we tried to jump start it and that did not help then we tried to push start it and when I released the clutch the back tires locked up. The reason I think the engine seized is because the tires lock up when being push started, the engine wont turn over all I get is a click. I also recently replaced the clutch and I was wondering if that had any thing to do with it locking up. The car right now is completely stock with 160000 miles.