'87 Ranger 5 speed

[leftlane36]

I ask for help a few days ago on IDing a ranger transmission. Well I found out which one I have but I know that it is supposed to have 80-90W gear oil in it, but I pulled the plug and it had been filled with ATF. My question is I have a loud knock in it that gets louder after it warms up, could the ATF not be doing what its should. Before I pull it out does anyone think it would be worth putting gear oil in it and trying it out before taking it out and rebuilding it. I probably dont put 1000 miles a year so I hope I can get out the easy way. IT IS 4 Wheel drive. Also I have a case of LUCAS 85W-140 gear oil in the garage would that be OK in the transmission or do I need something else.

 

[RangerX]

So which transmission IS it?

 

[leftlane36]

It is the FM145. Sorry

 

[MrShorty]

My question is I have a loud knock in it that gets louder after it warms up, could the ATF not be doing what its should. Before I pull it out does anyone think it would be worth putting gear oil in it and trying it out before taking it out and rebuilding it.

There's no question that ATF is much thinner than gear oil. Where your transmission is designed for gear oil, I wouldn't be surprised if the ATF is not providing sufficient lubrication.

It is possible the transmission is beyond help and needs to be rebuilt. Considering how easy and cheap a drain and refill would be, I'd be tempted to at least putting the right fluid in there to see what happens before going to the effort/expense of rebuilding.

 

[leftlane36]

MrShorty I think I may just put the right oil in it to see what happens. But I kinda got lucky a while back I bought a roll over that was still running. I was able to get a motor(sold) both diffs, trans and transfer case out of it. So I think I will just get ready to do a swap and rebuild the one that is in it now so I will have a spare that I know is good