Crazyeights Posted April 10, 2010 Share Posted April 10, 2010 So, I bought a 3.7 LSD from baccaruda and converted it to 3.9 for use in my old EA81 wagon. We were talking about different transmissions and he came up with an idea for a nice combination. I started with a low mileage (53k) RX trans. I pulled the 3.9 ring and pinion set from an old XT6 parts trans I had laying around and set them up in place of the 3.7 gears in the RX box. I had to switch washers under the pinion nut (from the other trans) to keep the clearance on the pinion assembly correct otherwise it was too tight once assembled and the nut torqued. Other than that, the shim stacks on both pinions were nearly the same so no worries about depth. The pattern looked very good right off. I set the backlash at about .008-.010 (only about 1 notch looser that it would have been). Next I went out to Pull-A-Part and found some (EA82 SPFI) 23 spline stubs and put those in so I could use the stock EA81 axles. It went together really easy and it's nice and quiet. I pulled out my 5 speed D/R and installed it almost 2 weeks ago and it's GREAT! Full time 4WD - Center Locking diff and it's still a D/R but not quite as low geared in low range. Just about perfect for the street. 2-5 gears are a little lower than the old D/R and low range on the 3.9 RX box is good for about a 500-600 RPM increase in each gear. I didn't take any pictures of it apart because the threads below show the exactly the same parts. These people and many more I'm sure, did all the hard work of writing the tear-down threads I used for reference or I never would have even tried it. I have a couple cheesy cell phone pics of the trans and the LSD but haven't quite figured out how to put them in a message yet. Thank You baccaruda The Beast I Drive Gloyale Numbchux Quote Link to comment Share on other sites More sharing options...
Txakura Posted April 10, 2010 Share Posted April 10, 2010 That is pretty cool. Quote Link to comment Share on other sites More sharing options...
The Beast I Drive Posted April 10, 2010 Share Posted April 10, 2010 If you get an itch to tear down the tranny again, I would swap in the low range gears from a regular 3.9 D/R trans, so you have the low reduction and the shorter RX gearing:banana: I was wondering when the first 3.9 RX/XT6 trans would be put together... Now I just need to put together my 4.11 AWD D/R, and get a custom pinion made for my 4.444 project -Bill Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted April 10, 2010 Author Share Posted April 10, 2010 It would be an easy swap but the D/R I pulled out is complete and I didn't want to rob the parts from it. I'm watching P-A-P for a parts D/R for a first gear sychro and the low range aux set. Thanks for all the ideas:banana: Quote Link to comment Share on other sites More sharing options...
Numbchux Posted April 10, 2010 Share Posted April 10, 2010 cool! But, I hope you either have oversized tires, or you don't spend any time on the freeway. I couldn't stand the ridiculously low gears on the freeway with the stock RX trans. I can't imagine converting it to 3.9! yikes!!! Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted April 10, 2010 Author Share Posted April 10, 2010 It has a 3" SJR Lift with 15" Peugeot 8 spoke alloys on it. Right now the tire size is 215/70/15 which seems about right. Quote Link to comment Share on other sites More sharing options...
Numbchux Posted April 10, 2010 Share Posted April 10, 2010 nice, than that should be pretty good. my 215/65r15 snow tires made it just barely liveable, so your extra height and slightly lower gears should be pretty decent. good work! Quote Link to comment Share on other sites More sharing options...
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