Will this transmission work ?

[97Mule]

I found a good ZF-5 out of a 1992 4x4 diesel, will this work okay in my 1997 4x4x PSD ? Please advise. Thanks for your input.

[bugman]

Yes, it will work but the torque rating is lower and the gear ratio is different than the one stock ZF for a 97.

[97Mule]

Thanks for the reply. I think I read where it maybe 420 ft./lbs versus 470 in our PSD's. What are the difference's in ratio ?

Thanks

[bugman]

The transmission out of the 91 will be a ZF42 with a torque rating of 420 ft-lbs and they came with two different sets of gears, here are their ratios:

Standard gear ratios on the ZF S5-42:
Close Ratio
1st Gear: 4.14
2nd Gear: 2.37
3rd Gear: 1.42
4th Gear: 1.00
5th Gear: 0.77
Rev Gear: 3.79

Wide Ratio
1st Gear: 5.72
2nd Gear: 2.94
3rd Gear: 1.61
4th Gear: 1.00
5th Gear: 0.76
Rev Gear: 5.24

Your transmission out of the 97 is a ZF47 with a torque rating of 470 ft-lbs and here are its ratios:

Standard gear ratios on the ZF S5-47:
Close Ratio - 7.3L Diesel
1st Gear: 5.08
2nd Gear: 2.60
3rd Gear: 1.53
4th Gear: 1.00
5th Gear: 0.77
Rev Gear: 4.66

Wide Ratio
1st Gear: 5.72
2nd Gear: 2.94
3rd Gear: 1.61
4th Gear: 1.00
5th Gear: 0.76
Rev Gear: 5.24

[97Mule]

Okay, Thanks. How do I tell if they are close or wide ratio ?

[Snowtow]

If it's out of the truck put it in first gear and count the revolutions of the input shaft needed to turn the output one revolution.