Found a 5 speed trans out of an '89 f250 gasser (351). I am toying with the idea of swapping this into my truck in place of the existing c6. I need an overdrive desperately.

First off, can anyone tell me what kind of trans might have been behind a 351 in 1989? Also what are the gear ratios? Is there a sticky or reference page on this site with this information? I can't seem to find it. I just found out the AOD gets 0.667:1 gearing in overdrive. Does the 5 speed come anywhere close to this or better????

Also, what else might I need for the conversion? I will be getting the clutch pedals as well but does this typically include a clutch slave cylinder? I have no clue how these years manuals work.

Thanks!

 

'89 F250 will have the ZF5 for a manual. Very good tranny. 5.71:1 1st gear and I think .75:1 OD

Is this going in the '84 in your sig? It will physically bolt to the engine and the Tcase will bolt to it. Might need to steal the cross member and drive shafts if the trans is a different OAL. The clutch setup I'm not sure about. Best bet is to grab the whole truck to reduce the trips to the parts store or the JY.

 

Bingo! You can google the ratios if you want all of them - there are several sites with them.

The small-block ZF's had an integral hydraulic slave cylinder, so you will have to go hydraulic. And, since your truck doesn't have a manual tranny you'll need the clutch/brake pedal assembly from another one of these trucks awa the master cylinder - not an assembly from the '89 as it won't fit. Please note that the early years of these trucks had manual clutch linkages, so you'll need one from a later year truck. And, you really need to get the firewall stiffener bracket since Ford didn't design the firewall to handle hydraulic master cylinders and adding one will probably crack your firewall - some year. So, do some searching on this forum and you'll find someone giving a link to where you can get the bracket/stiffener and install it now - before the firewall cracks.

The clutch set, meaning clutch disk/pressure plate/pilot bearing/throwout bearing, should be one for your engine. And, you will need a flywheel for your engine.

 

ZF S5-42 – 5 speed manual transmission has an aluminum alloy main gear case and tail housing with the bell housing integral to the case.

The ZF S5-42 is built in both a 2 wheel drive and 4 wheel drive version with gas and diesel designs

ZF first introduced the S5-42 in 1987 and was used in the Ford F250, F350, F450 and Super Duty trucks until 1994.

All gears on the S5-42 are fully synchronized with an input torque rating of 420 ft-lb

Standard gear ratios on the ZF S5-42:
<table cellpadding="0"> <tbody><tr> <td> <table cellpadding="0" width="166"> <tbody><tr> <th colspan="2" scope="col">Close Ratio </th> </tr> <tr> <th scope="row" width="85"> </th> <td width="73"> 4.14 </td> </tr> <tr> <th scope="row"> </th> <td width="73"> 2.37 </td> </tr> <tr> <th scope="row"> </th> <td width="73"> 1.42 </td> </tr> <tr> <th scope="row"> </th> <td width="73"> 1.00 </td> </tr> <tr> <th scope="row"> </th> <td width="73"> 0.77 </td> </tr> <tr> <th scope="row"> </th> <td width="73"> 3.79 </td> </tr> </tbody></table> </td> <td> <table cellpadding="0" width="166"> <tbody><tr> <th colspan="2" scope="col">Wide Ratio</th> </tr> <tr> <th scope="row" width="85"> </th> <td width="73"> 5.72 </td> </tr> <tr> <th scope="row" width="85"> </th> <td width="73"> 2.94 </td> </tr> <tr> <th scope="row" width="85"> </th> <td width="73"> 1.61 </td> </tr> <tr> <th scope="row" width="85"> </th> <td width="73"> 1.00 </td> </tr> <tr> <th scope="row" width="85"> </th> <td width="73"> 0.76 </td> </tr> <tr> <th scope="row" width="85"> </th> <td width="73"> 5.24 </td> </tr> </tbody></table> </td> </tr> </tbody></table> The ZF S5-42 main case cast number is “1307”

 

Also, it has been my understanding ( I am planning on doing a zf swap for my 4spd) that the earlier versions of the zf tranny did not have an integral slave cylinder. I am not sure what the years are for that though. My local junkyard (they specialize in ford 4x4s) said that they would grab me one of those types, but did not mention what year range it was.

 

The diesels have the close ratio gear-sets and the gassers have the wide ratios. The outside of the case has a waffle or criss-cross pattern of ribs. And, they are heavy. I can pick up a C6 or an NP435, but not a ZF5.

Only small-block ZF's had the integral slave cylinder, the 460 and diesel pattern ones didn't.

 

My zf5 was much lighter then any cast iron truck transmission i have ever messed with. You must have one of those foreign iron zf5s. This swap is super easy and well worth it. Some people have even used the c6 driveshafts with the zf5 becuase they are so close in overall length. Around 1" differance i believe

 

No.
The Windsor pattern ZF's had an internal (concentric) slave cylinder.
The Lima and diesel ZF's had an external slave and throwout arm.

ZF5- 42 or 47 did not matter.

 

The 89 clutch pedal assembly will not bolt in to a 86-down truck. You need an assembly from a 83ish-86 truck.