most common rear end gears

[kid]

No my NP435 is on the floor getting cleaned and up to reverse and my 250 with T18 is out there being held on a hill with reverse down and locked.

[FLATBEDFORD]

That's very strange. The VIN plate on my truck indicates T18. Reverse is up and to the right. I have and NP 435 out of a '67 F350 and reverse is down to the right.

[theskytoucher]

My truck has a t-18 also (side of the case says so) and reverse is right and up!!!!

[kid]

LOL my NP435 is a NP 435 now my VIN on the 250 says T18 and the PTO plate is in the right place for one. I will dive deeper into mine.

[averagef250]

Kid, I've rebuilt them for a decade or better and driven them for hundreds of thousands of miles. T-18 reverse is up. 435 is down.

[kid]

Okay my NP is not down I will check my 250 and really see what is in it but my NP435 is a NP435 and is up.

[averagef250]

Here's the surefire way: 435 top-aluminum. T-18 top-cast iron.

[ToughOldFord]

As long as it's original. I put a T18 in my '79 when the NP blew up. The T18 didn't come with the shift tower, so the one of the NP went on.

[kid]

250 iron top 350 is aluminum top.

[69bluef100]

Our old t-18's are right and up, T-18s made after '77 or so are right and down

[kid]

As long as it's original. I put a T18 in my '79 when the NP blew up. The T18 didn't come with the shift tower, so the one of the NP went on.

How did you put a NP top on a T-18? NP is 8 bolt and T-18 and 19 is 6 bolt.

[ToughOldFord]

Don't know what to tell you, that was a lot of years ago and I knew less about these trannys back then vs what I know now which still isn't much. My original transmission dumped it's third gear so I drove for a while jumping from second to forth, but when second went I had no choice but to fix it. I pulled the tranny, smashed the *^&^$#$ out of my finger when it slid off the jack. Took it to the transmission shop and they ID'ed it as a NP and said it was so messed up I could buy a new one from Ford for less than it'd cost to fix my old one. I shopped around and found a T18 at a local yard, they told me I wouldn't know the difference other than reverse was in a different position. I bought it, but it didn't come with the plate/shift tower, but the yard told me my old one would work so I took the old one off and bolted it right up. Everything worked fine 'cept reverse was now opposite than the knob said.
If it shouldn't have worked then you got me, but it did.

[zakt]

gear ratio calculator:

http://www.rocky-road.com/calculator.html