The Mazda 5-speed in my 1990 Bronco died last week. Aamco wants to rebuild it. Bottom line cost is $1000-$1500 (or more possibly). How much more would putting a ZF tranny in cost me?

Is a new clutch needed for the ZF? Will the shift tower hole in the floor and tranny cross member line up correctly?

 

I just finished reading through the ZF has landed thread. There was a log of good info there. But I'm still not sure what is required for this swap.

Will the clutch & flywheel from my mazda tranny work? Or do I need the one from the ZF?
Also do all the driveshafts, crossmembers and the shifttower hole in the floorboard lineup correctly?

 

From what I've read here (in the tranny forum), it's a direct bolt-in swap. Same clutch/flywheel, same xmember and driveshafts. I haven't heard of the shifter hole not lining up, so you should be ok there. Please note though that M5OD and ZF use different shifters.

 

Okay, so a different shifter is the only thing needs to be changed?

I just got off the phone with the Aamco mechanic who started telling me that I would need a new drive shaft, master/slave cylinders, and everything. But he was talking about an external slave cylinder and clutch fork which is only on the ZF for the bigblock. So I'm not sure how much his advice matters. Will this really be a simple swap or am I looking at getting stuck with a huge bill when all is said and done?

 

Only if you get it done at Aamco. If you do the swap yourself you can pretty much do it for the price of the tranny.

 

I'd love to. But I have no garage, very few tools and it is quite winterly outside.

 

Then you're pretty much at the mercy of whoever's going to do the install for you. Driveshafts do not have to be modified, as the tranny is basically the same length. But I wouldn't expect the Aamco guy to know that.

I would very seriously consider whether or not you want to let Aamco do any work on your truck. Go to the general automotive conversation forum here on FTE and read the thread about underhanded mechanic tricks. Chances are you'll never let anyone work on your vehicle again.

 

I've been using the same mechanic's shop for four years now. I trust him a lot. Unfortuently the shop is too small for this job. When I told him I had a clutch/tranny problem he said he could probaly change the clutch if that was the problem but anything more then that would be too much.

 

The clutch for the Mazda, should be a 10" clutch, and the ZF clutches typically are 11" clutches. I just replaced my ZF clutch if you want to see it here step by step more or less...

http://frederic.midimonkey.com/f350-clutch.html

If your clutch for the Mazda is the 10" clutch, then you have to have the flywheel redrilled to match the new clutch. Not a big deal, but it's not a "guy in a garage with a drill press" operation unless you are darn sure you can locate center, and the holes properly. I am guessing, but a machine shop can drill and tap the six holes for about $75.

The ZF is physically larger than the Mazda, however looking at both of them I would guess that the shifters are "about" in the same place, at least close enough you don't have to hack holes in the floor. Remember that the F150 cab was used on the F250, F350 and F450 chassis' and the bigger F-series had the ZF, and used the came factory made cutout in the floor. So that shouldn't be an issue.

The crossmember can be recycled, however I do believe you have to move it back one set of bolt holes. Assuming that my F350 crewcab is typical, I had four sets of crossmember bolts and my ZF was on the 2nd set closest to the engine. Not sure why there were four sets, considering there were only three transmission choices for the F-series in 1993 (Mazda, ZF gas, ZF Diesel) and the two ZF's use the same mounting holes. But, replacing the tranny mount and moving the crossmember as necessary, should allow that to fit fine.

The driveshaft may have to be lengthened or shortened. Your best bet is to find an F250/350 in the junkyard that has a ZF, and take that driveshaft. Obviously you want the shaft off the same wheelbase. If you have an extended cab, long bed, find one of those in the junkyard (or car-parts.com) and have the shaft balanced and slap it in with new u-joints and that problem is solved as well.

You can have a driveline shop lengthen or shorten your shaft if you can't find a useful junkyard one, and that's not terribly expensive either.

The small block ford ZF itself typically sells in the 500-800 range on ebay for a used one, more for a fully rebuilt, warrantied one. I waited a year to buy one while shopping on ebay, and snagged a BBF ZF for my project for a mere $350. Sometimes it pays not to be in a rush, but I do realize your current transmission is hosed.

The ZF clutch kit costs anywhere from $200 to about $500 or so, and you'd want to install a new $100 slave cylinder if it's not included in the clutch kit. While it's open, and apart, since it's a real PITA to do so, might as well make all the hard-to-get-at bits new and not have to worry about it for a long while.


If you want to stick with the Mazda tranny, for the prices you got quoted to have yours rebuilt, I'd just buy two junkyard Mazda's for 1/3 that price and install one, keeping the other as a spare.

 

His should be 11". The earlier transmissions used a 10" clutch

 

Cool, makes it even easier.

 

Thanks for your post but you have really confused me. Other people have said the ZF and mazda are the same length and will line up bolt for bolt, driveshaft for driveshaft. You are talking about the big block ZF right? Maybe that one is longer but the smallblock ZF shorter to match the length of he mazda?

 

The ZF for SBF and BBF are the same length.

I haven't seen the Mazda and the ZF side by side, but I've seen them individually, and I vaguely remember the Mazda being a tad longer, and using a different u-joint.

I certainly could be wrong, I'm quoting from memory from helping a friend with his F pickup a few years back.

If the majority of people here are saying they are the same length, I'd be inclined to go with their advice, as for me it's been quite a while.

ZF's I know. Mazda's... well, lets just say it's been a while.

KNow that it wasn't my intention to confuse you.

 

Ask MustangGT221 in the Windsor forum. He took the ZF from an F250 and put it in an F150 and took the M5OD from the F150 and put it in the F250. He should be able to tell you whether there were any crossmember or driveshaft changes.

 

If you look at the thread the ZF has landed, the guy says it's so close that he didn't have to change driveshafts at all.