I've searched on this a lot and I've come up with a few major MKIII R154 swap threads (Shern's in particular) but in this one below there seems to be a suggestion that using an MKIII transmission mount with a modified MKIII crossmember will work.

This concerns MKIII R154s with the parallel bolt holes for the rubber mount. R154's with the offset holes can use the SC300/MKIV W58 rubber mount and that's not the transmission I have (or that Shern had in his car).

Can anyone confirm this? I have both an MKIII rubber mount and MKIII crossmember to experiment with.

https://www.clublexus.com/forums/per...-my-sc400.html

Otherwise I think my only alternative is Driftmotion's MKIII R154 mounting kit which uses billet spacers for the crossmember. I'm wary of that solution, honestly.

I am also looking up the 1991 Soarer R154 transmission mount but I fear it may also be near identical to the 92-97 W58 mounts we use.

 

It probably is nearly identical since us with Soarer R154 swaps just use the W58 mounts.

 

from my research im pretty sure you use a modified sc300 crossmenber and a mkiii trans mount.
Pretty sure you have to drill out the sc300 crossmember to accept the mkIII mount.

 

I used a stock sc300 crossmember with a w58 mount and modified it to fit. Worked fine for me.

 

Thanks guys. I know some people can use the SC/MK4 W58 mount on their R154's but I have one of the MKIII versions with parallel bolt holes for mounting. I think I'm limited to the MKIII mount or Driftmotion's mount kit that modifies the SC300 crossmember.

So there is no way to use the MKIII R154 crossmember with the MKIII mount by re-drilling the chassis mounting holes?

At the very least I don't want to use a the SC/MK4 W58 mount because I don't like only two of four bolt holes lining up when the transmission transfers so much torque.

 

i wouldn't use the drift motion kit, its way over priced, just get a sc300 cross member and drill out the 2 holes and use your mkiii mount

 

I'm not concerned about the price of their kit. It's well thought out. I just don't like that I have to lower my crossmember to use it.

I'm set on using the MKIII mount but do you know if it's possible to modify the MKIII crossmember to bolt this up? I have one that came with my R154 so I'm game to try if it means modifying less hardware than using my SC 5-speed crossmember.

 

If you are dead set I would use the sc300 crossmember and weld
Up the currently holes and redrill to fit the sc300 crossmember with the mk3 mount.

 

I love it when I get "token expired" and my post is completely eaten.

Anyway, the only thing I am dead set on is mounting the transmission properly with all the bolt holes on the gearbox being filled (so no SC/MKIV W58 mount). I am not a welder but I do have access to a medium size drill press.

Here are a couple of interesting examples I've found:

http://www.celicasupra.com/forums/sh...538#post762538
This guy welded what I think is an SC crossmember with a plate for the MKIII mount.

http://www.supraforums.com/forum/sho...=1#post5294903
And in this one the poster uses a Chaser R154 crossmember to mount the R154 into his MKIV Supra. I can't tell what the mounting holes for the transmission mount look like though.

https://www.clublexus.com/forums/3524696-post10.html

But still this one above is the most interesting to me. The OP just drilled out the chassis bolt holes on his R154 MKIII mount and fit that into the SC chassis with no welding.

I like the last option best if it will work, although a Chaser Crossmember would be ideal since it is very similar to the SC300 crossmember. Barring either, I'll probably just get the Driftmotion kit.

And then there is this interesting thread: an IS300 owner came up with a steel plate mount for the MKIII R154. I'm sure this doesn't work in SC's.
http://my.is/forums/f114/new-crossme...pacers-444254/

Edit: The above picture of a crossmember is not what came bolted to my R154. The one in the picture appears to be wider. Can anyone identify what vehicle it came from? It fits the MKIII R154 mount without issue from the look of it.

 

Okay, I have to know: can anyone identify the strange crossmember in the picture from the post above? It isn't an MKIII R154 mount (those have uneven sides).

It looks like it could be a stock-ish solution to mounting these MKIII R transmisssions.

 

I believe it is a stock OEM MKIII one.

 

1JZPWRD, I've identified 2JZLEX's crossmember: it's from a 1982-1985 Celica W58 5-speed. The mounting holes for the W58 transmission tailshaft are VERY similar to the tailshaft mounting holes on the MKIII Supra R154 and the for holes in the center of the crossmember should fit either mount as we've already seem. The chassis bolt holes probably still need to be modified to fit the SC but a Celica is definitely what it came from.

Here are some pictures to support this:


http://www.celicasupra.com/forums/sh...322#post810322



Modified but still the same crossmember.


And still we could try something similar to the welding/cutting or custom-made steel solutions in either of these threads:

http://forums.tdiclub.com/showthread...=359959&page=3

http://www.celicasupra.com/forums/sh...nversion/page2

 

Looks like he added a lot onto it, i dont understand why you wont use a sc300 w58, all you have to do is drill out 2 holes..
no fabrication or welding required.

the mkiii r154 is wide enough to even come close to mounting, i know because i have one and i mocked it up the other day. you would have to add at least 2-3 inches on each side, then line it up and drill out 4 holes.

 

In the second example picture the crossmember had been welded. It wasn't being modified for an SC application. It's just the few decent pictures I could find of the Celica crossmember.

The SC transmission mount isn't going to support the R154 as firmly as will the MKIII R154 mount. I prefer not to modify something so critical as a transmission brace.

As for the MKIII crossmember, I have one too and it's totally incompatible. But this is why I'm using the 82-85 Celica W58 crossmember. As 2JLEX posted in his thread, it fits the MKIII R154 mount without modification and only requires slight drilling out of the chassis bolt holes. It is apparently a very close fit to the SC chassis. I found a clean one off eBay that I should be getting in this week to test with.

 

The Celica crossmember came in today. I test fitted the MKIII R154 mount and it bolted up perfectly.

Here you can see a comparison with the MKIII R154 crossmember and the 82-85 Celica W58 crossmember.





This should be the very same part 2JLEX used in his swap.

The unfortunate thing is that Toyota discontinued or sold out of these some years ago, so used is your only option if you want to do it this way. The plus side is that this should allow the use of a factory Toyota transmission mount with an MKIII R154 transmission.