5 Speed Tranny

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ChrisIB
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5 Speed Tranny

Post by ChrisIB »

I'm looking into replacing or upgrading a 5 speed transmission in a 04 turbo, due to some operating frustrations to say the least. My fourth gear grinds when engaging in gear at higher RPM's. I have been told it could be a cloth, but that doesn't sound right to me. I changed the fluid and the rear diff fluid. I notice a ease in changing gears but the grinding issue remains. I live in Colorado. There is only one place with more Subaru's and that's Japan. Salvage and junk yards are full with Subies. I think I'm going to pull one, and also purchase a new clutch and fly wheel with tranny mounts for the swap. Looking on the internet I found that Baja Turbo Trannies are code TY754VHEAA. I know the Forrester XT has the same gear ratio's, but a different code. My question is, can I upgrade my tranny using a different model and will it bolt on or use a different model to replace the tranny? Also I think I'm thinking too hard into it. But then again why does the 04 Forrester XT tranny and the Baja Turbo tranny have a different part number?
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anarchy1024
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Re: 5 Speed Tranny

Post by anarchy1024 »

I think I saw a thread on NASIOC a while ago that listed the different transmissions, part numbers, and which were compatible/interchangeable..... Or maybe I'm just dreaming... but it could be worth a look. Sorry, don't have enough experience to give you reliable answers.
ChrisIB
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Re: 5 Speed Tranny

Post by ChrisIB »

Thanks for your time.
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anarchy1024
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Re: 5 Speed Tranny

Post by anarchy1024 »

There should be someone else on here who has a better idea.... anyone?
hocrest
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Re: 5 Speed Tranny

Post by hocrest »

Here is the tranny list showing all of the gears. http://spda-online.ca/content.php?44-transmission-chart

Whatever trans you use, you MUST match the FD (4.11 or 4.44) or also swap the rear diff.

All of the other trans codes will have slightly different ratios for each gear. As long as the FD matches they will fit and work fine. You may have slight changes to where you are used to shifting though.
ChrisIB
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Re: 5 Speed Tranny

Post by ChrisIB »

hocrest wrote:Here is the tranny list showing all of the gears. http://spda-online.ca/content.php?44-transmission-chart

Whatever trans you use, you MUST match the FD (4.11 or 4.44) or also swap the rear diff.

All of the other trans codes will have slightly different ratios for each gear. As long as the FD matches they will fit and work fine. You may have slight changes to where you are used to shifting though.
Thank you very much for your time. I'm trying to grasp this please forgive me. I'm going to disregard the ratio's because thats way out of my tax bracket. So your saying that if I decide to swap which is the smartest approach to take; I got to make sure I use the same rear diff?
hocrest
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Re: 5 Speed Tranny

Post by hocrest »

There are 4 main components to the Subaru driveline.
- transmission, reduces the engine speed into controllable great ratios
- center differential, takes the output from the transmission and splits it to the front and rear
- front differential, takes output from center diff, reduces the revolutions and splits it to left and right wheel.
- rear differential, takes output from center diff, reduces the revolutions and splits it to left and right wheel.

On an AWD Subaru the first three components are all combined in the front transaxle. Generally when people talk about swapping a Subaru transmission, they are not taking the transaxle apart and just swapping the transmission, but are actually swapping the entire transaxle.

So in normal operation, the engine spins, turns the transmission input, you select a gear and the transmission output spins. Let's say it's spinning at 100 rpm. The center differential is going to transmit the same 100 rpms, to the front and rear differential. With both front and rear diffs having a final drive 4.11 ratio (for every 4.11 times that the input spins, the output spins once), it will spin both front and rear wheels at 24.33 rpm.

If you keep a 4.11 rear diff, but change the transaxle to a unit with a final drive 4.44 ratio, now your rear wheels will still be spinning at 24.33 rpm, but the front wheels will be spinning at 22.52 rpm. This would cause binding and things to break.

So if your going to swap the from transmission (transaxle) first determine the final drive your Baja has. Under the hood, there is a stamped metal plate fastened to the drivers side strut tower, it has the VIN, engine code and transaxle code. Look up the transaxle code in the chart I linked. It will identify your FD ratio. When shopping for a replacement trans, it will have a sticker on the side with the transmission code. Look up the FD ratio for that trans. If it is the same, everything will work fine. If it is different you will also need the rear differential with matching FD to swap with your rear diff.
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