kilowatt Posted October 25, 2009 Share Posted October 25, 2009 I have a 1993 Loyale 4wd 5 speed MT. The transmission went bad so I bought a used one with 45k miles. The new one seems to work great untill I engage the 4wd. It seems to have a different gear ratio to the rear end. I jacked-up one side of the car, engaged 4wd, put it in gear and the front and rear wheels turn at different speeds. Is it possible that the transmission and rear differential gear ratios need to be matched? Did Subaru use different ratios in the rear end that need to be matched with the transmission? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 25, 2009 Share Posted October 25, 2009 Yes. The push-button 5 speeds came in 3.9 and in 3.7. Your Loyale should be 3.9 so it may be that your used tranny came from an older 3.7 car. GD Link to comment Share on other sites More sharing options...
kilowatt Posted October 25, 2009 Author Share Posted October 25, 2009 Yes, my rear diff is a 3.90. The used transmission that I got is a vacuum 4wd and it is marked as a carb. I told the seller that my car was SPFI. When the tranny got here, and I noticed it was marked "carb" I figured that it wouldn't matter carb of FI. But evidently it does, because a carb car would be older and therefor more likely to be 3.70....Right? How do I know for sure when I get the next one, if it's 3.90 or 3.70? Thank you very much for your expertise! Link to comment Share on other sites More sharing options...
The Beast I Drive Posted October 26, 2009 Share Posted October 26, 2009 Dont go through all the hassle to swap the tranny out again, just swap out the rear diff with a 3.7 unit to match your 45k mile tranny. Much easier As for how to tell, the only thing I can think of would be check serial numbers against the dealer database, or count rotations... It was somewhat random as to which cars got 3.7 trannys and which ones got 3.9s, but IIRC all Loyals got 3.9s, all DL's also got 3.9s, and all Turbos got 3.7(with 25 spline axles stubs vs. 23 spline on all the other ones) so it must be some GL's that got the 3.7s, but I have found a couple that had the 3.9s even though they were carbed. Also, if you decide to swap to a Dual Range 5 speed, most of those were 3.9 from 85-89, the only ones that were 3.7 were the RX dual range 5 spds w/Diff lock, but those also had a higher low range and are more for Rallycross then offroading. They also had the 25 spline axle stubs instead of the 23 splines that the 3.9 Dual Ranges had. -Bill Link to comment Share on other sites More sharing options...
kilowatt Posted October 26, 2009 Author Share Posted October 26, 2009 As much as I HATE the thought of swapping the tranny again (I'm sore today, must be getting old) I don't really want to spend more money on this project. Also, this car is 99% commuter, so I don't need dual range. If I had low range, I'd just go wheel it and brake it. Besides, it is gutless enough without going to 3.70 gears. That would lower my rpm to mph, right? If I do strike out in getting the right tranny from this seller, who has a 3.70 rear diff and how much would it cost? Link to comment Share on other sites More sharing options...
kilowatt Posted October 26, 2009 Author Share Posted October 26, 2009 Oh, I just thought of another reason to go through the agony of changing the tranny to the correct one. The switches are different between the two trannies. The plugs are different, the locations are different, and the neutral switch length is different. So I get a check engine light because it never sees the neutral switch change. Link to comment Share on other sites More sharing options...
Gloyale Posted October 26, 2009 Share Posted October 26, 2009 Besides, it is gutless enough without going to 3.70 gears. That would lower my rpm to mph, right?If I do strike out in getting the right tranny from this seller, who has a 3.70 rear diff and how much would it cost? You already went to 3.7 gears. When you drive in FWD you are using the 3.7 final drive of the front diff. Swapping the rear diff won't make any difference. It will just allow the rear ro be engaged without fighting the front. Strange thing to me, is that most of the carbed cars got 3.9 dual ranges. The tranny you got must be from an 86 non turbo GL-10 .Only the GL-10s got the single range in 85-87. An 85 GL-10 would be MPFI, an 87 GL-10s where only Turbo(which would have had 3.7, but with 25 spline stubs) IDK.......but yeah if it is a highway on;y car just swap the diff.....easy.....I got a 3.7 diff I could sell ya for $20......pm me. Link to comment Share on other sites More sharing options...
kilowatt Posted October 26, 2009 Author Share Posted October 26, 2009 That sounds great but I still have the issue with the neutral switch. Can I just jumper the neutral switch so that the ecm thinks that it's always in gear? Or will that cause some other issue? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 26, 2009 Share Posted October 26, 2009 You can install a pedal switch on the clutch pedal to act as the neutral switch. That works well enough that you won't get the code. GD Link to comment Share on other sites More sharing options...
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