DominicLeeWadkins Posted September 17, 2019 Share Posted September 17, 2019 Alright, so I got my hands on a Ea81 transmission (4h,4L) and I want to swap it into my 88. I also got the backing plate so that the starter won't be an issue expect I heard you might have to use some shims? I'm also curious about the drive shaft are the yokes the same, will I have to cut or add to the drive shaft? Are the cross members the same? The main question I have before I dive into this project. Will I have to change the gear ratios in the front and rear axle? If anyone can help me with info for the swap I would very much appreciate it. Thanks. Link to comment Share on other sites More sharing options...
el_freddo Posted September 17, 2019 Share Posted September 17, 2019 My question is: WHY?! The 5spd box is superior in just about every way to the 4speed box. You’ll have to customise the tail shaft or see if the one piece unit fits. If your L series is carb, the driveshafts will fit no worries. You’ll have to work out the gearbox mounts. Really though it’s a waste of time. Put a 5 speed in. If it’s the dual range you’re after, wait for/buy a dual range 5speed - avoid the turbo gearbox as it’s got a poor low range reduction compared to the NA boxes. Cheers Bennie Link to comment Share on other sites More sharing options...
Steptoe Posted September 17, 2019 Share Posted September 17, 2019 My EA82 auto was 3.45:1 front diff while 3.7 in the bum - work that one out ! Hope you also got the EA81 tailshaft Link to comment Share on other sites More sharing options...
idosubaru Posted September 17, 2019 Share Posted September 17, 2019 (edited) 9 hours ago, DominicLeeWadkins said: Alright, so I got my hands on a Ea81 transmission (4h,4L) and I want to swap it into my 88. I also got the backing plate so that the starter won't be an issue expect I heard you might have to use some shims? I'm also curious about the drive shaft are the yokes the same, will I have to cut or add to the drive shaft? Are the cross members the same? The main question I have before I dive into this project. Will I have to change the gear ratios in the front and rear axle? If anyone can help me with info for the swap I would very much appreciate it. Thanks. i wouldn’t mention this normally but since you’re doing a swap and have a lot of questions, clarity may help. I think you mean final drive ratio, not gear ratio (meaning the different gearing of 1st, 2nd, 3rd...). Final drive ratio is the front and rear differential ratios and is independent of the transmission gear ratios. You’ll want the front and rear diff ratios to match. And you mean differential, not axle. The final drive ratio is dictated by the front and rear differentials not the axles...but I understand in truck world an entire rear assembly is an “axle”. The final drive ratio should be the easy part, subaru didn’t use many different ones in the 80s. All 88 EA82/ER27 are 3.7 or 3.9 and interchange with each other. EA82 nonturbo manual should be 3.9. A quick USMB search shows EA81 might be 3.9. If that’s the case you don’t need to do anything for final drive ratios, the front and rear diffs match. But like mentioned - you’re going backwards from most in terms of installing that 4 speed. Edited September 17, 2019 by idosubaru Link to comment Share on other sites More sharing options...
carfreak85 Posted September 17, 2019 Share Posted September 17, 2019 7 hours ago, el_freddo said: My question is: WHY?! The 5spd box is superior in just about every way to the 4speed box.... Bennie Fixed it for you... Link to comment Share on other sites More sharing options...
skishop69 Posted September 17, 2019 Share Posted September 17, 2019 I wouldn't do it for the reasons mentioned above and others. Third gear is GOING to go out on the 4spd. It's a known issue. You're going to need the EA81 flywheel and tranny mounts. Mounts will need to me modified as will most likely the shifter linkages. Cutting and welding. Probably going to need a custom driveline as well since the trannys are different lengths. Don't ever recall anyone going backwards like this so I still say, don't do it. Link to comment Share on other sites More sharing options...
FerGloyale Posted September 17, 2019 Share Posted September 17, 2019 Don't do it. So much work for no gain. EA81 flywheel will need holes bored out to fit EA82 crank. Crossmember needs modded to fit EA81 mounts. Clutch cable likely won't reach,(fork on the other side) need EA81 cable and then how to mate it to EA82 pedal box? Driveline would need to be shortened or use 4spd 1 piece. Shifter may not even lineup int he same hole.....might..........But D/R lever for EA82 won't work with EA81 since it's part of the EA82 shifter, which goes away. Just don't do it. Wait and get a 5-spd D/R Link to comment Share on other sites More sharing options...
DominicLeeWadkins Posted September 17, 2019 Author Share Posted September 17, 2019 Okay, I want to thank everyone for your opinions and saving me a lot of work. So I'm swapping my EA82 engine (88 fuel injection) into another 88 cause my current body is all beat up. The guy I'm buying the new parts car from had a couple of those old Ea81 transaxles and I always thought it would be cool to have 4H,4L. But now that I know that my 5 speed is superior I'm going to just swap the engine and original transaxle into the new body. The car I'm buying is an automatic but it's also an 88. Is there anything I should be aware of like motor mounts and transmission mounts? Cause if every thing lines up, all I have to do is cut a hole for the cane. Link to comment Share on other sites More sharing options...
el_freddo Posted September 17, 2019 Share Posted September 17, 2019 Engine mounts are the same. Use the manual gearbox crossmember from memory. I think you need the manual tail shaft too. If you’ve got the two vehicles the physical swap will be easy. Going carb to MPFI is either an entire loom swap from your current subi into the new one (basically you’re doing a reshell), or you pull the wiring from your current subi and cut it down to just the MPFI wiring to run the engine - then put this into the recipient vehicle. The wiring will be where the work is unless the replacement/recipient subi is also MPFI. Move been there done that with carb to MPFI. With the amount of work done I could’ve done an EJ conversion in the wiring department... Cheers Bennie Link to comment Share on other sites More sharing options...
Steptoe Posted September 18, 2019 Share Posted September 18, 2019 As long as the auto box is not the 4 speed E4AT that some late turbos got, they had different gearbox mounts. Gave mine away to someone so no pics Link to comment Share on other sites More sharing options...
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