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Discussion Starter #1
Hey guys, now that my car is running properly, the wheels in my have been spinning :D. The auto in my car sucks, plain and simple. I want a 5 speed. What is entailed in this swap? Will I want a W58 from an MKII, or a manual from an MKI? I assume I will need a crossmember and driveline from a manual MKI. Who's done this, what do I need, etc?

Did any MKI's come with an LSD stock? I realize that a true-trac is the way to go, but those are $$$$. Any other options (short of welding the spider gears to the carrier like I did in my truck 8) )?
 

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Manual Mk1's came with a W50, so the easiest option is to grab one of these and bolt it in. The W58 is a better box but you'll have to modify/fabricate a transmission crossmember to make it fit. You may also need to shorten/lengthen the tailshaft.

Mk1's were available with an LSD, but AFAIK they're not common. They have an F series diff centre so they're interchangeable with some Toyota truck diffs, and with some parts swapping (ie bearings) you can use a Mk2 diff centre as well.
 

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Discussion Starter #3
Can anyone tell me approx. how much RWHP a W50 would be good for?

Norbie- can you give me any details on what it takes to swap in an MKII diff into my rear? I assumed that I had an 8" rear, it strongly resembles the diff that is in my truck. I guess I should get an FSM or something.
 

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Sorry, I don't know any specifics but I read somewhere that the bearings in the Mk1 are a different size to the Mk2, but you can mix'n'match to make it work. Mk1's definitely have a 7.5" diff.

W40/W50's are fairly strong, in fact they are popular with the rotary drag cars around here because they're cheap and plentiful. The W50 has a known weak point though - if you put too much torque through 5th it will strip the gears. It shouldn't have a problem with a NA M series engine though.
 

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Discussion Starter #5
I'm planning to go turbo, which is why I'm thinking the W58....but if the W50 is up to the task, that sounds the way to go. I can avoid "getting awn it" in 5th gear easy enough, just downshift! Thanks Norbie!
 

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Sam,

If your rear diff is anything like mine, you probably have a 3.73 Non-LSD Rear!!!!! I also thought that the MKI's had LSD rear's, but apparently, I've been reading the rear diff firewall code WRONG all of these years. Which means that the 3.91 diff that was in my 80 MA46 was also a Non-LSD rear as well.

But yes, I did confirm the code on my 81 Silver Slug Auto that it is indeed a 3.73 Non-LSD rear, so your's should be the same.

Don't know of anyone who has installed a LSD rear into the MKI solid axle carrier.

As for the tranny, I'm honestly not sure if the W50 will work w/ the 5MGE. The W58 is a safe bet, but try either one. Good luck!!!
 

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Discussion Starter #7
Thanks Chris. I think I'm gonna go with a W58, crossmember fabbing and having a driveline made is no problem for me, and I wouldn't have to worry about strength then. I'm going to look for a Toyota pickup IFS front diff with an LSD installed and then have a shop change out the bearings, I think that will work well. Thanks for all your help.

Sam
 

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Discussion Starter #8
Curiously, does anyone have a pic of a W50?
 

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I don't have a pic, but I have a W50 sitting on my garage floor... I could get a pic of it if you like. It's out of a Celica but it should look much the same as a Supra box.
 

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Discussion Starter #10
Norbie said:
I don't have a pic, but I have a W50 sitting on my garage floor... I could get a pic of it if you like. It's out of a Celica but it should look much the same as a Supra box.
that would be great, Norbie.
 
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