I have two transmissions that I got for free from the junkyard how can I test them to see if they work they go in a 99 f150 I would rather not put both in to find out they both don't work

  • Welcome to Motor Vehicle Maintenance & Repair! Are these automatic transmissions you're talking about? If so, about the best you can do is check the fluid to see if it's burnt. Other than that, if you don't have a transmission dyno just laying around, there's about no way to my knowledge to test them prior to putting one in. Commented Feb 24, 2022 at 18:57

1 Answer 1


It is more inspection than testing. I am obsolete; worked in an independent trans shop long ago, all mechanical mechanisms- no electronics. But some things are the same:

  • Open the pan and check wear debris, in a good modern trans the pan should be pretty clean (last one I looked at was a 1985 Nissan 300 ZX at 100,000 miles, very clean). The oil should not smell. Burned bands, etc, can make the oil smell bad.
  • Check for bent blades in the torque converter. My boss knew trans pretty well; with the valve body open , he put air pressure into various ports and operated the clutch and band servos.
  • Be sure to put in new seals, front and rear.

More than that would be dismantling the trans, or testing of the electrical components, which would need the manual. On the other hand, back then there were shops that would get trans from the junk yard and sell them as reconditioned. They hired semiskilled labor to bolt them in; no trans knowledge needed. If it didn't work , bring it back and bolt in another.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .