On a 13, 15, or 18 spd the drop rate is about 300 rpms per gear. on a 9, 10, super 10, or srtaight 8, is about 500-600 rpms, if your an experienced driver floating the gears (using rpm band, not the clutch to shift).

 

So the tranny out of my 94.5 F250 7.3 4x4 should go right in my 97 F250 7.3 4x4 ?

Here I was told they would not, that the 42 cannot replace the 47 because the wrong year.

If I would only lose a little torque, I don't mind because my 94 pulled great. And I liked how it shifted better anyway, I could float anything over 2nd.

I know this is an old post, but hope someone replies for a second opinion that this is ok before I start tearing apart the 94 when the rain stops!

Thanks for the hope that I might actually get a truck running this week!
I had been limping around in my 84 F250 non-4x4 until last month, when I think it blew the head gasket.

 

Yes, the 42 will bolt right up and work in a truck that had a 47

 

the 42 and 47 are a lot of the same.

Though, I don't know about the year thing. Travis has a 95 and he's got a 42 in his truck. He bought a 47 to replace his though.

The 47 has some more useful upgrades like a non pressed in throw out bearing shaft.
On the 42, you have to disassemble the case, with the 47 you do not.
Some other upgrades and such as well.

If you look at the pictures, they are very similar, but they made some case modifications to them as it appears to me.
As for input torque. Look at cody and the other guys on here with sled pullers running this.

The biggest fear on a zf5 is snapping the input shaft. Which... Is actually pretty hard to do.
Other than that, the other worry is worn bushings, which all transmissions have to worry about.

 

8?-95= S5-42

96-97= S5-47

 

I wish a NP205 would bolt up to it...

 

Here's some info directly from ZF. It's specific to the 42 but some can be implied and applied to the 47.
http://www.thedieselstop.com/faq/949...load/S5-42.pdf

 

These transmissions are not interchangable the 47 has an overall longer lengthcase from bellhousing to the tailshaft. Also if you would install a 42 where a 47 should have been originally equipped you will not get proper support between the pilot bearing and the input shaft. You will have only a 1/4 of insertion and the bearing and the shaft both have 1/8" of bevel ( to aid in insertion) so you have no real support and are doomed to mechanical failure. This I know from personal experience.

 

Good to know, thanks.
I will avoid the 42 swap for sure then, it had been a gut thing not to go with it.
I haven't been able to do anything yet, needed a truck asap so had to defect to a 92 dodge (only decent truck I could find on short notice). I am still looking and these 47s are not easy unless I want to shell out $1800-2500, which I don't have right now. (plus extra new parts and install)
Thanks again.

 

http://www.zf.com/na/content/media/u...NAL_2-1-09.pdf

Straight from ZF

 

There are several people who have swapped the 42's onto a 95-97 7.3 with no problems, and seeing that it came stock in the 94.5 PSD and it is the same block as a 95-97 PSD I dont' see any problem with using the 42 on one of those engines as long as you use the proper flywheel/clutch for your application.

The driveshafts may be different lengths but any ZF5 from a '88-97 7.3 will fit the engine.

 

Evan if you really want a 205, the divorced model behind a two wheel drive tranny with custom drive shafts make it very possible.

 

I've thought about it, but I'd rather keep a married t-case so I'm going to use the trans/t-case from my '88.

I just think that the np205 is one of the better factory t-cases out there, cast iron case and gear driven instead of aluminium and chain drive.

 

I have a 92 idi with a zf s5-42 that just went up. Should i think about putting a zf 5-47 in it. If so will it work with my flywheel or do i need the bigger one. And do i need to get a shorter drive shaft.

 

Evan,

You can absolutely mount an NP205 (married version) to the ZF tranny. You just have to notch the transfer case mounting flange on the ZF. This is (relatively) commonly done in dentside trucks to retrofit an overdrive transmission where one wasn't available stock. If you search the 73-79 forum for zf swap, I'm sure you can find the info. The ZF case also has a boss for mounting the transfer case shift lever though you may have to fab up a linkage piece. Good luck!