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XT6 manual transmission noise.... Upgrades?

Transmission upgrade

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12 replies to this topic

#1 Caboobaroo

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Posted 06 January 2013 - 01:49 AM

Long story short, my '89 XT6 is starting to whine at high speed once the fluid is warm so it will eventually need a rebuild. It is possible this transmission could stay with either an EG or EZ swap and I'm trying to figure out what would be reasonable. I have a few newer generation Outback, Legacy and Impreza transmissions but only one XT6 box.

So, opinions matter, what would you do if you were in my situation and faced with these decisions? One of my biggest peeves is the highway engine rpm as its too high for a 6 cylinder at cruise:dead: it can kill gas mileage...

Edited by Caboobaroo, 18 July 2013 - 11:32 PM.


#2 Turbone

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Posted 06 January 2013 - 12:56 PM

Either 3.7 or 3.9 is your only choices if you want to keep your mpg.
And you'll need a adapter with a EJ trans (which I have) :brow:

#3 grossgary

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Posted 06 January 2013 - 01:01 PM

so true, cruising at 4,000 rpms seems crazy to me and gets old. that would be the one thing I'd be looking to change, lower the cruising rpms. part of that happens with larger tires of course which i think you have already. but some more gearing changes would be nice if possible.

i don't think EA82's or XT Turbo's cruise that high rpm but i'm not well versed in gearing so i don't know what to make of it.

#4 Caboobaroo

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Posted 06 January 2013 - 02:50 PM

Well from what I've read, putting any other final drive behind a EZ30 besides a 3.70 will make it scream on the freeway. I miss having the RX dual range box in my coupe as it was great behind the EA82 SPFI engine that was in it.

I'm also curious as to different gear sets from EJ transmissions and how they bolt into the XT6 case. Also, I'm curious about swapping 5th gear with something a bit taller, again to help with freeway rpms.

Oh and I forgot you had that adapter plate:headbang:

#5 Turbone

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Posted 06 January 2013 - 03:24 PM

Install a 6spd :-p

#6 Numbchux

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Posted 06 January 2013 - 07:24 PM

Well from what I've read, putting any other final drive behind a EZ30 besides a 3.70 will make it scream on the freeway. I miss having the RX dual range box in my coupe as it was great behind the EA82 SPFI engine that was in it.

I'm also curious as to different gear sets from EJ transmissions and how they bolt into the XT6 case. Also, I'm curious about swapping 5th gear with something a bit taller, again to help with freeway rpms.

Oh and I forgot you had that adapter plate:headbang:


Any Phase 1 gearset will drop into the XT6 front case halves (phase 2 got a beefier reverse gear, and therefore the idle shaft is a bit further away from the main shaft. no way to get around this in a phase 1 case). Center diff and housing will have to match front pinion shaft, of course.


I ran my '88 XT6 with trans internals from a '94 AWD Impreza. 4.111, I think taller 5th than XT6. I loved it, don't remember what rpms I was turning on the freeway, but no complaints.



If you're planning a swap, I'd baby this trans until then. Fresh fluid (Extra S!), and be a little gentle on it. It'd be worth it to be able to use an EJ pressure plate with a new-gen H6!

#7 Caboobaroo

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Posted 07 January 2013 - 12:07 AM

Well the engine swap will happen but this will probably be a few years from now (moving this summer, getting married, other projects) and I just went through the engine in it currently. Only complaint is the amount of power but it's currently fairly reliable and I have a spare ER27 in the garage. My other option is to build a beefy NA ER27:clap:

#8 Caboobaroo

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Posted 18 July 2013 - 11:31 PM

Time to bring this back up as I have more questions come the pending transmission rebuild.

I think I'm going to keep it a 3.90 for now seeing as I'm daily driving it again. With that being said, I'm looking at a phase 1 EJ transmission to swap the guts over. I'm guessing from the looks of it, the center diff housing will bolt right on, which means I will need to use the EJ mount. Will this change the length of the overall transmission, this requiring me to shorten the front half of the driveline? Are there any particular transmissions I should look for?

I've scored a few items over the last few months hopefully I can use in this swap. First, I picked up a set of Cusco solid engine mounts and matching transmission mount from an STi. Then, last weekend, I picked up a OS Giken TS2B twin disc clutch setup for almost nothing, hoping to use in the swap. Figure I can redrill the flywheel to fit. While I'm in there, I plan on doing some Whiteline transmission crossmember bushings. Would there be any reason why the clutch will not work with my setup? It came from a first gen Legacy and is set up for a push style clutch.

#9 Numbchux

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Posted 19 July 2013 - 04:14 AM

You're right on the money with the center diff. It will bolt right up to the XT6 front case. It will require an EJ mount. And it will require a shortened driveshaft. Shift linkage will be slightly different, but it's close enough to work (shift lever will be angled a little closer to the dash un-modified).


The clutch might be possible, but I don't think it's been done. EJ and EA/ER pressure plates and flywheels are pretty different. I don't think it would be possible to use that clutch kit on an EA/ER flywheel, and the EJ flywheel will not engage the starter correctly. You might be able to mod the starter/mounts to solve that problem, but it won't be easy.




75 mph with stock XT6 gears (3.90 and .780 5th) on stock XT6 tires (23.7"), 3234 rpms. Change to EJ AWD 5MT gears (4.111 and .783 5th) only bumps it up to 3422. about 200 rpm change. Jump to EJ sized tires, and you gain it back (205/55r16s = 24.9" = 3257 rpms).

I loved the 4.111s in my '88 XT6. That engine never ran right, and I still got better mileage then my '89 4EAT which ran beautifully.

#10 Caboobaroo

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Posted 21 July 2013 - 03:00 AM

So the driveline shortening, guessing its the same size chunk you would take out of an EA82 driveline when doing the EJ transmission. I was planning on modifying the ends of the factory linkage to work with the newer style joints seeing as it looks like they will swap so welding a couple bits together isn't an issue.

The starter, now that is concerning. Maybe I should get my hands on an EA82/ER flywheel and see what differences there are.

I also had a thought about converting to the EJ push style hydraulic setup. If I can get my hands on a junk EJ transmission case, would you think it's possible to cut it the boss for the slave and weld it into the same spot on the XT6 transmission. I would cut out the same section on my transmission and then tig weld the piece from the EJ transmission into my bell housing.

Also, the XT6 uses the same throwout bearing as a first generation Legacy or Impreza on a push style clutch. This clutch was in '91 Legacy wagon that was lifted. Guy said he couldn't run it because of medical issues, too stiff for him to push. Thus, another reason why I'm contemplating trying to convert to a hydraulic setup over the cable... Just need to see if I can make the flywheel work.

#11 bluto5

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Posted 22 July 2013 - 05:46 PM

I have also been considering what to do with flywheel options.  spec isnt rating their er/ea clutch offerings very highly for lb/tq and hp.

 

Chopping the bell housing to relocate the starter might be a nice option if its viable.  the flywheel ring gear height is roughly 3/4-1" different.

 

Rather than cut from another trans, if only the bosses were wanted, it would probably be easier to weld on some new ones.

 

Why the desire for hydro clutch?

 

Sam



#12 Caboobaroo

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Posted 04 August 2013 - 07:20 PM

With the higher rated clutch, I'm partial with converting to a hydro clutch. If I can make it work, I will try using the cable system first.

#13 Caboobaroo

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Posted 22 August 2013 - 11:13 PM

So I might be able to get my hands on a couple spare transmissions. There might not be an XT6 transmission so would another EA82 case work for my swap? I gotta get this done, mine is starting to make more noise now that I'm daily driving it...




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