Transmission crossmember
 

What's the difference between a S4 n/a manual and S5 n/a manual transmission crossmember?
Are they interchangeable?

I ask because my S5's center bush is trash- the part the y-bracket stud goes through- but the junkyard cars are all S4s.
Mazdatrix list them as separate part #'s (with the S4 being more expensive) but they look very similar.

the part where it bolts underneath the car is different. I think on the s4 has one side at an angle and the the s5 has both sides flat.

the Y blocks that mount to the transmission are not interchangeable with the crossmember...they are different shapes. i think the actual crossmember mounting points are the same (unless auto) but the shape is slightly different. i dont see why the center bushings would be different but have never tried swapping them.

Is the center bushing- the one in the crossmember- actually replaceable?

It looks like Mazda wants the entire crossmember replaced, I see no listing for just the bush.

No, not that I aware of. Once the Y trans mounts collapse and causes the center bushing to push out, a new crossmember is the only replacement.

Well that's just silly.

Spending $80 to replace the entire metal brace just because a rubber bushing has failed is unacceptable.
Further investigation is required...

And already done. The tranny mount has a welded plate covering the bushing. No way to press it out or to press a new one in.

Aargh.

The mount can be a different series from the trans and car but you need the complete mount to make it interchangeable.

i dont think so. the mount can be a different series from the CAR, but needs to match the transmission.

Well, Monday I think I'll go to the yard and see if the S4 there has a crossmember worth picking.
If so, I'll grab it and the y-bracket and see what's what.

the s5 Y bracket has 2 bolts that attach to the transmission on each side. the s4 has one bolt on each side and is much wider. the s5 Y bracket will not fit the s4 crossmember and vice versa.

you can however mount an s5 transmission into an s4 car (or vice versa) if you use the same series Y block and crossmember as the transmission (auto's excluded).

Argh, WTF? Lame :(. Mine is shot too, and I was hoping to maybe replace just replace the bushing with something else.

Correct. End of Story. As long as the tranny has a crossmember it will fit into either series car but the crossmembers are not interchangeable between series to fit on the tranny. I tried already.

^^ This is true. Also the s5 turbo or n/a are both the same. (cross member that is)

If you REALLLLLY wanted to, you could drill/tap new holes in the tail housing to match the bolt pattern. This would require you to use both an S4 y-block and S4 crossmember. But doing this would also require removing the entire tail housing to prevent metal shavings from getting inside, so it's probably not the route you'll want to take. As mentioned, S4 y-blocks attach via 2 bolts on the bottom of the transmission, while the S5 versions attach via 4 bolts on the sides.

i wonder if you could use a hole saw and drill out the entire bushing...im sure someone could find a suitable replacement for next to nothing.... probably something better than stock too.

Not according to Mazdatrix, 2 different part numbers:
89-92 Manual Trans. non-turbo 39-3700-FC02
89-92 Turbo 39-3700-FC18

So, it doesn't appear that the S4 parts will do me any good.

Next step will be to drop my stock crosspiece and investigate a repair.
Or, I could just bite the bullet and buy new pads and crossbrace and be done.

Naah...what fun would that be?

I just pulled my cross member for my 1991 convertible NA. The insulator bushing as Haynes calls it is indeed replaceable. Mine is ready to crack into bits and just fall out while a new one could be pressed in from the top down. The problem is Mazda does not list the part so I was hoping someone had a source.

I cleaned up my old bushing and am going to fill the formerly rubber area with urethane, 3M Windo-weld I bought at Advance for $18. Like this sort of: http://www.mazdas247.com/forum/showthread.php?t=72087

I need to know the dimensions the steel bushing in the center is suppose to have in relation to the outer sleeve or cross member so i can line it up properly. Can anyone measure the depth relation for me?

Back from the dead. I have run into this problem and I have a fix that seems to be working. I removed the mount, pressed the old bushing out and made a new rubber bushing. I took a piece of scrap rubber from the bottom edge of a snow plow, its about an inch and 5/8 thick. I then took a hole saw that would make a rubber plug that is slightly larger than the hole. i drilled most of the way through, then on the other side i drilled it larger to make a lip so the bushing can't be pushed through. Picture it looking like an inverted top hat. I then installed fender washers on the top and bottom of the bushing for stability. I then took the car out and did a couuple of hole shots, and hit the back roads pretty hard. There was minimal (non existent) transmission movement and no noise.

That was a good idea. The 3M Widow-weld was good but I never really packed it in there hard enough. I just squirted it in and there was lots of air but it still worked. I would recommend hand packing with rubber gloves on.

I just scoured the shelves of the local parts store and found a control arm bushing that was a perfect press fit in.

Share! Part number? Pics?