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02 Outback 2.5 Auto 05 Outback 2.5 Auto
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Discussion Starter #1
Long time watcher but just joined as I need help that I can't find even after much searching.
Trying to find the diff ratio of an automatic trans. There are lots of manual lists, but I can't find any for the newer 5EAT.
The trans number is TZ1b7LCACB. I believe this is not the original trans, all the searching I have done says this is an Outback XT trans, where my car is just plain Outback.
I am pretty sure when the previous owner changed the trans they did not get the correct rear diff to match as the car does bad torque bind when you take out the AWD fuse.
I think the trans is good, passes all the tests so far and works great in FWD mode, I just need to know what the front diff ratio is so I can find the correct rear to match.
If anyone knows a way to decode the number or can give me any info I would really appreciate it.
 

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2006 Subaru OUtback XT
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90 Posts
First, I do not have the answer to the gear ratios.

The older Legacys had 3.90:1, 4.11:1 and 4.44:1 and if you put a 4.11 behind a 3.90 it would BIND like crazy.

What I think may be your issue is tires not being all the same exact size. This will cause a binding issue.
 

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Lawn ornament XT
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14,368 Posts
If that came from an XT it's a totally different trans... 5 speeds instead of 4, totally different setup.

It's not going to be a clean swap into a 4EAT car.
 

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Master Caster
2005 XT, Mildly Modified...2006 XT Limited, Highly Modifed
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16,150 Posts
This is in the car?

This can't be right. The trans have different mounts, different wiring, different filter location. There has to be mistake. Are you sure you don't have an H6?

Take a picture of the console shifter in this car.
 

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02 Outback 2.5 Auto 05 Outback 2.5 Auto
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Discussion Starter #5
It's a 5 spd with sport shift. Has a big electrical connector coming directly from where the cable attaches to the trans. The 4eat is different. I have used the sport shift to check all the gears and I know it has 5 so it has to be a 5EAT. I just need to figure out how to know what the diff ratio is.
When I put that trans number in Google, pretty much everything that comes up says it belongs to an 05 Outback XT.
SO, did the Outback XT have different ratios than the regular Outback???
Anyone???
 

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. . . The trans number is TZ1b7LCACB. . . If anyone knows a way to decode the number or can give me any info I would really appreciate it.
From the attached (FSM/General Information/Identification), that transmission is a 4AT, multi-plate full time transfer system, originally installed in a Legacy or Outback with a 2.5 SOHC engine.

Unfortunately, the number does not indicate the year, so we can't look at model year specifications to determine the final ratio. Perhaps the last three letters (ACB) might help . . .
 

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02 Outback 2.5 Auto 05 Outback 2.5 Auto
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Discussion Starter #7
I did a rotate and count test of the rear diff that's in the car and it's a 4.44
I found a few places that says the 05 Outback 5EAT is supposed to be 3.52 or something like that.
If they really put a 4.44 rear with a 3.52 front, no wonder it binds like crazy.
 

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Discussion Starter #8
From the attached (FSM/General Information/Identification), that transmission is a 4AT, multi-plate full time transfer system, originally installed in a Legacy or Outback with a 2.5 SOHC engine.

Unfortunately, the number does not indicate the year, so we can't look at model year specifications to determine the final ratio. Perhaps the last three letters (ACB) might help . . .
Holy cow, now I am really confused. Did they have the sport shift thing on 4EAT's? I'm going to have to drive it again and count the shifts closer.
I have found many indications that this car was "messed with" a lot. The computer had the case removed and was just the board sitting under the carpet. I had to replace the ECU, BIU, and the TCU to get the car to start and drive. All 3 were bad.
I know the trans has been out because not all the bolts/nuts are there.
Really never should have bought this car but it's to late now.
Thank you for that trans decode chart, that is exactly what I have been looking for. Do you have anything that shows what an 05 Outback 4EAT front diff ratio is supposed to be?
Thanks again.
 

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02 Outback 2.5 Auto 05 Outback 2.5 Auto
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Discussion Starter #9
I must apologize, I think I got the sport shift thing wrong. What I was thinking sport shift was, and what it really is are two different things. My bad.
When I put the shifter into the push forward or back place, I have to push it back 4 times before it drops into low gear, that is what confused me.
So I still need to know what the proper differential ratio is for an 05 Outback 4EAT.
 

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Holy cow, now I am really confused. Did they have the sport shift thing on 4EAT's? I'm going to have to drive it again and count the shifts closer. . . .

Do you have anything that shows what an 05 Outback 4EAT front diff ratio is supposed to be?
Thanks again.
The 4AT will mechanically shift through four gear ratios, but it will also partially apply the torque converter lock-up in 2nd and 3rd gear, as well as in 4th, under low or moderate throttle. When it does, the rpm will drop (in my experience usually 200 rpm or less), and this could be misinterpreted as a gear change (although gear changes have larger rpm changes).

According to the 2005 FSM, the 2.5 Outback, non-turbo with 4AT used 4.444:1 final ratios at the front and rear differentials.

Unfortunately, this still doesn't help identify the gear ratio of the front differential that is part of that replacement transmission.

(Attached table for 2005 rear differential, which therefore defines what the front differential in the transmission assembly should be.)

. . . I know the trans has been out because not all the bolts/nuts are there.
That only suggests it (or the engine) was out at some time, and that not all the fasteners were replaced; however, it doesn't mean the transmission that's in there now isn't the original.

. . I have found many indications that this car was "messed with" a lot. The computer had the case removed and was just the board sitting under the carpet. I had to replace the ECU, BIU, and the TCU to get the car to start and drive. All 3 were bad.
Certainly a messy situation, but with the transmission code indicating it's a 4AT, are the replacement modules for a 2005 2.5 non-turbo with the 4AT or 5AT?

Also, as has been mentioned, are all four tires the same brand/model/size and tread depth (i.e., same rolling circumference)?
 

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Again, I do not think you could drive it at all with a 4.44 in the rear and a 3.52 up front. You'd be dragging the slower speed rear tires around BIG TIME.
 

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2005 OBXT Limited, VF37, STI intake, 5MT
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With the transmission code you posted, that is 100% a 4EAT. The 5EAT transmissions start with TG5Cxxxxx.

Edit: The last edit didn't take, apparently, but here's more info.

The "CACB", according to opposedforces says it's for a 2.5L SOHC Outback Wagon U5 (Cali emissions). This should be correct to your car, a 2.5i Outback.

You could just have nasty torque bind from the donor car. If mismatched tires or never-changed fluid was used, the transfer clutch just might be toast.
 

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Discussion Starter #13
Sorry for delay, got busy with Christmas.
Thanks for all the info, I think I have it all straight now. The trans is a 4EAT with sport shift, and it's the original trans. The one I got from the junk yard that I was going to put in was a 5EAT without sport shift. Electrical connections are completely different, won't swap, at least easily. I had both trans numbers written down and I was researching both and forgot which was the original and which was the replacement.
In any case you were right about the 4EAT in that car, and about the 4.44 gears in the rear, as I checked that.
So I put the original trans back in. Ran it with the FWD fuse in, works great. Take the fuse out, torque bind like mad. Although it seems to be a bit better. I read somewhere that a person changed his trans fluid 3-4 times to really get it mostly replaced, and he said it fixed his torque bind problem.
I also read that you can unplug the trans control harness, jack up one side of the car, mark the tires and put the car in gear. If the two diffs are the same the tires will rotate at the same speed. I'm going to try that next.
I already tried the go in circles 20 times thing, impossible to do with the fuse out, car would buck like crazy. Did it with the fuse in, no help. I was seriously dizzy and light headed for 2 days after that, not going to do that trick again!
One bright spot in all this, there is a fuse under the hood that is not marked. The map under the lid does not even show that location. I took the FWD fuse out and stuck it in there just to see what would happen. The radio now works, the security system now works, and the cruise control works. Finally something is getting better!
 

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I also read that you can unplug the trans control harness, jack up one side of the car, mark the tires and put the car in gear. If the two diffs are the same the tires will rotate at the same speed. I'm going to try that next.
I don't think that applies to the automatics with limited slip differentials.

If the FSM chart attached earlier is correct, the rear differential is limited slip. With one side of the car raised, engine running, and in gear (it would be 1st or 2nd) the raised rear wheel will spin fairly freely. The LSD (presuming it is still working) will then transfer torque to the opposite wheel on the ground, and as it appears the transfer clutch is fully engaged with the fuse out, the torque from the transmission output could cause the car to move forward on the jack(s).

The idea of raising one side does apply to the manual transmission, where, with the engine off and the transmission in gear, manually turning one of the raised wheels should cause the other raised wheel to turn the same amount, but in the opposite direction, allowing the rotation to be counted. In this case, because the wheels are being turned quite slowly, the rear LSD will allow the raised wheel to rotate without transferring the manual turning torque to the opposite wheel.
 

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2005 OBXT Limited, VF37, STI intake, 5MT
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You cannot easily swap-in the 5EAT. 100% of the components related need changed from the flexplate back. For the record, all 5EAT have sportshift.

The "fixed" with the fuse-in tells me you have a functioning fluid passage and duty C solenoid. Doesn't mean there isn't mechanical damage, but the lack of torque bind with the fuse-in is telling.

I would try to obtain a USB-to-OBD2 cable and using RomRaider or FreeSSM, you can "watch" the front and rear wheel speeds.

It sounds like the TCU is cutting-in the duty C when it should not be. Or you have mismatched ratios/tire sizes and the TCU is trying to compensate.
 

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A simple check would be to take a string and wrap it around all the tires to see if they are all the same diameter. If 1 tire is larger or smaller, you will torque bind.
 

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Discussion Starter #17
I tried the jack up one side and rotate, with the trans unplugged the car wouldn't even turn over. So I plugged it back in and it actually worked. It seems like both were spinning the same, but it's really hard to watch both at the same time from only a few feet back:nerd:
Best I can tell they rotated the same, when I shut the car off, the marks were still in the same places.
All 4 tires are the same brand and almost new. Air pressure is within 2 lbs. I', reasonably sure it's not the tires. I have owned and driven many Subies and never had mismatched tires cause torque bind this bad. When you turn the front wheels sharply it feels like the car is going to start hopping and you can hear it thumping.

My best guess is that the signal to the center diff is not working like it's supposed to. I know the clutches lock in, I know they unlock completely when the fuse is in. What is does not do is partially release like it's supposed to. The system is supposed to supply varying amounts of front to rear split, and only go to full 50/50 if the front is spinning much faster than the back indicating loss of traction.

Problem is, that may be a computer issue, maybe wiring, loose connector, could be lots of thing. I have both cables and the software to read both ECU and trans codes, guess that is what I'll have to do.

Thanks again for all the help, I was really confusing myself and you all put me back on the right track. Gotta love these boards!
 
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