Hey guys I have an 84 F-150 4x4 with a 300 six cylinder. I am considering an overdrive transmission. I currently have the 4 speed with a granny gear and hydraulic clutch. I know Ford made a 3speed with overdrive for these years. I am wondering is there a late model 5 speed that will work without major modifications, or should i stay with the 3 speed?

 

I think there is a "small block" version of the ZF5 (bell housing bolt pattern is the biggest
concern), check out this (I know it's about a 460 but it might still be useful):

https://www.ford-trucks.com/forums/7...-pictures.html

 

Easy use, no tow/haul/major hills?

Mazda 5 speed, from behind 300/302 in F150.

Harder use, tow/haul etc, ZF from behind 300/351w in F250.

4 speed OD? Big gap 2nd to 3rd. Top shift or Single Rail boxes are aluminum and considered weak. Bearing issues. OD weak.

Domestic Truck Tranny Guide

 

I would recommend the ZF5 over the M5OD simply for the fact of still having granny gear. Having driven a truck with the M5OD for work, in comparison to my truck with a T18 and my stepdad's K2500 with the NV4500, there are some situations where the granny is just nice to have. You can stick it in gear and let it creep out of the parking spot, or out of the snowdrift, instead of having to rev and slip the clutch constantly. Not to mention the advantage when towing or trying to drag/push something around.

 

Since you have a 4x4, you will need to find a transmission for a 4wd. The M5OD is a lot more plentiful in 4x4 trim than the ZF, simply because the M5OD was only offered in small block fitment. The ZF could be found in F250/350 trucks, but you would need to find one that was both 4wd and 351W powered.
Let's not forget that the M5OD is longer than the 4OD, so you would need to address both driveshafts, longer front/shorter rear. The ZF, I'm not sure about the length. Some say it's the same, others say it's longer. So, I have no idea whether you would need to modify the driveshafts or not.

 

The small block ZF5 has the internal, concentric slave cylinder.
The BB and Diesel versions have an external slave.

The ZF (in big block form at least) is the same length as the T-18/19 and it's separate bell housing.

 

Thank you guys for all the information--I love this site. Would love to have my granny gear and eat my cake too. so the zf would be the tranny for me,,,but is there an adaptor plate for the big block to small block so I could also have an external slave???

 

No adaptor plate.

Some have adapted the TO to a conventional set up, but I couldn't tell you how or on what model trans.

As for prior post, some BB ZFs used an external slave, but afaik, all ZFs are integral bell.

Adapting to a hydraulic clutch isn't too tough, as you can probably use OEM Ford parts from a later model.

 

BTW the other option is the NV4500, but that would co$t more than the ZF, which i$ already enough....

 

I would not recommend the 4 speed overdrive. I have one in a 1986 and it went bad with less than 70,000 miles on it. The mechanic said these have a bad reputation. I'm going to spend quite a bit to have it rebuilt. I didn't really have any options. My last F150 was a 1984 300ci 4x4 with the transmission you have. That truck had well over 200,000 and the transmission was still problem-free. The granny low comes in handy.

Rick

 

Thanks again guys all your help and time is greatly appreciated.