I currently have an '88 F150 4x4 with the 302 & 4 spd manual. Does anyone know what 5 spd manual trans was available that year? Also, would it be difficult to swap it in? From what I've read in this thread, it appears the ZF was not offered behind the 302.

 

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Ford had three options for all trans: small block, big block, and diesel.

All small blocks are interchangeable including autos (if you want to do that much work). For your question, the M5OD appears to be the preffered trans to match the powerband of the 302 the best. You can swap in a ZF but it will be sluggish.

Mike

 

The Mazda M5OD, also called M5R2, is the F-150 five speed transmission. They seem to get some undeserved bad press, but they're excellent transmissions. I own two of them, one 4x2 and one 4x4. The ZF is the heavier unit used in F-250s and up. It's an outstanding transmission, but more expensive and difficult to find in the small block pattern. It is also available in dedicated 4x2 and 4x4 versions. You'll need a 4x4 version.
Either transmission can swap in, you'll probably need the crossmember and brackets that go with the unit you're swapping in. You'll want to replace the concentric slave cylinder before installing an M5R2, about $70. It cannot be easily replaced once the transmission is in, so best to start with a new one. If you can, put the trans in first gear and remove the shift tower to look at the gears. Make sure the brass colored blocker rings teeth are still triangle shaped - not rounded on the top, indicating wear. The gears should not be discolored -ie, blue or dark on the teeth, indicating overheating. Note - on the M5R2 at the back of the shift tower are three rubber plugs which seal the shift rods. These can shrink up and leak, causing the transmission to run out of fluid while driving. This is a primary cause of failure. Make sure any donor trans has plenty of fluid in it and no evidence of overheating the gears.

 

Thanks for the info. I am curious if the transfer case and drive shafts would be the same between a 4x4 truck with the 4 spd manual and 5 spd manual?

 

You'll need to make a measurement on your transmission, from the front of the bellhousing to the rearmost flange of the transfer case adapter (the section between the transmission and transfer case. I'll be glad to measure my 4x4 M5R2 for comparison. If the measurements are very different, the driveshafts will be different lengths from yours. Your transfer case should bolt up - Ford uses a 6 bolt circle arrangement. Do you have a Borg-Warner 1356?

 

I'll have to measure it this weekend, then let you know. Also, I will have to see if there is a data tag on the transfer case.

 

Okay, I measured the distance from the front of the bell housing to the front of the transfer case: ~25 3/4 inches. I also measured from the forward face of the transmission (were it bolts to the bell housing) to the front of the transfer case: ~19 3/8 inches.


The data tag on the transfer case read as follows:

6128 1 1356-25
212497 E8T A-CA

It is a Bourg Warner unit.