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Gearbox problems

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Mon May 22, 2017 9:32 pm PostPost subject:
ayebalpaul
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Another question.

I now have Alex's spare box. It is from a 1996 STI and has a different final ratio,4.111 vs my 3.900. Can I use my rear diff or should I put the matching one in?

Was reading on the net, dangerous I know, and I believe I can pop the back plate off the diffs and make sure they have the same ratio's. That my best option??

Paul
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Mon May 22, 2017 10:23 pm PostPost subject:
AK
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If in any doubt use the matching diff... you DO NOT want to run unmatched gearbox/diff

Taking off the rear cover for diffs and reading the numbers is easy to do. From mem they are stamped (no of teeth on crown by teeth on pinion)... divide large by the small.

Then you have to consider the gearbox.... if known lol
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Tue May 23, 2017 7:12 am PostPost subject:
Arch
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ayebalpaul wrote:
Another question.

I now have Alex's spare box. It is from a 1996 STI and has a different final ratio,4.111 vs my 3.900. Can I use my rear diff or should I put the matching one in?

Was reading on the net, dangerous I know, and I believe I can pop the back plate off the diffs and make sure they have the same ratio's. That my best option??

Paul


Do you have the gearbox code for the box, there were not that many 4.11 Impreza's mainly early imports. As Adam mentions easy to check the diff ratio on the crown wheel, it's not that easy to see when wet but it is stamped on there. It's also easy to assume the gearbox is as it says but Sen people come a cropper if the tail cone has been replace. As an example I have a TY754VN6AA which has a FD of 3.9 with 1:1.1 drop gears giving rear diff ratio of 3.54 but I have changed the tail cone to one with 1:1 drop gears giving a rear diff ratio of 3.9 so always better to get diff and box at the same time especially when dealing with the less common boxes.
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Tue May 23, 2017 7:16 pm PostPost subject:
ayebalpaul
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Joined: 26 Jul 2016
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Location: Central Scotland

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Arch wrote:
ayebalpaul wrote:
Another question.

I now have Alex's spare box. It is from a 1996 STI and has a different final ratio,4.111 vs my 3.900. Can I use my rear diff or should I put the matching one in?

Was reading on the net, dangerous I know, and I believe I can pop the back plate off the diffs and make sure they have the same ratio's. That my best option??

Paul


Do you have the gearbox code for the box, there were not that many 4.11 Impreza's mainly early imports. As Adam mentions easy to check the diff ratio on the crown wheel, it's not that easy to see when wet but it is stamped on there. It's also easy to assume the gearbox is as it says but Sen people come a cropper if the tail cone has been replace. As an example I have a TY754VN6AA which has a FD of 3.9 with 1:1.1 drop gears giving rear diff ratio of 3.54 but I have changed the tail cone to one with 1:1 drop gears giving a rear diff ratio of 3.9 so always better to get diff and box at the same time especially when dealing with the less common boxes.


Hi Arch,

My box is a TY752VB3EA, RA box I believe, or so google tells me. The replacement is a TY752VB4AA, again checking online I believe its a 1996 STI box and I have the matching diff.

Cheers to you.and Adam for the help. Defo would come a cropper if I didn't ask and matched my diff to the new box... Really don't fancy taking it apart again.

Paul
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Sun Jun 11, 2017 10:27 pm PostPost subject: Gearbox
tommo
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Joined: 19 Jan 2012
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I use the ty752vb3fa and similar codes in my Impreza in the smrc last year 1 gearbox for the season this year I'm going onto my 3rd box and my cars 300hp @ wheels. Any info on how to make it last longer much appreciated
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Mon Jun 12, 2017 10:44 am PostPost subject:
AK
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Location: Aberdeen

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6speed
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Mini Race Car - SMRC
911 - 1981 Air Cooled 3.0
500 - 1969 Fiat 500 L
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Mon Jun 12, 2017 4:24 pm PostPost subject:
tommo
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AK wrote:
6speed
budget doesn't go that far + it's 35 kgs heavier
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Mon Jun 12, 2017 4:51 pm PostPost subject:
AK
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i was running about that power (400bhp) on a 5 sp (code TY752VB5CA) - supposed to be the strongest of that type... supposed to be. Has DCCD too which is a massive plus point in my opinion.

The TY54 (newer) are supposed to be a stronger casing too. I'd suggest a top of the line 54 would be the best bet. TY754VB1CA

Dont bother considering things like PPG dog boxes..... just a pain in the ass.

Either treat 5sp boxes as consumables or move to 6sp.

PS - i'm not buying you car has only 300whp Laughing It must weigh about 100kg less than ours if it does Very Happy
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Impreza Race Car - SLS/SMRC
Mini Race Car - SMRC
911 - 1981 Air Cooled 3.0
500 - 1969 Fiat 500 L
Toureg 262 RLine
Track Scotland
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Wed Jun 14, 2017 8:25 pm PostPost subject: Whp
tommo
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AK wrote:
i was running about that power (400bhp) on a 5 sp (code TY752VB5CA) - supposed to be the strongest of that type... supposed to be. Has DCCD too which is a massive plus point in my opinion.

The TY54 (newer) are supposed to be a stronger casing too. I'd suggest a top of the line 54 would be the best bet. TY754VB1CA

Dont bother considering things like PPG dog boxes..... just a pain in the ass.

Either treat 5sp boxes as consumables or move to 6sp.

PS - i'm not buying you car has only 300whp Laughing It must weigh about 100kg less than ours if it does Very Happy
Russ does a good job I'll show you my print out the first time I see I've got it lying in my van it's still got all the doors complete winders and glass 😄
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Wed Jun 14, 2017 8:31 pm PostPost subject: 4aa
tommo
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Joined: 19 Jan 2012
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ayebalpaul wrote:
Arch wrote:
ayebalpaul wrote:
Another question.

I now have Alex's spare box. It is from a 1996 STI and has a different final ratio,4.111 vs my 3.900. Can I use my rear diff or should I put the matching one in?

Was reading on the net, dangerous I know, and I believe I can pop the back plate off the diffs and make sure they have the same ratio's. That my best option??

Paul


Do you have the gearbox code for the box, there were not that many 4.11 Impreza's mainly early imports. As Adam mentions easy to check the diff ratio on the crown wheel, it's not that easy to see when wet but it is stamped on there. It's also easy to assume the gearbox is as it says but Sen people come a cropper if the tail cone has been replace. As an example I have a TY754VN6AA which has a FD of 3.9 with 1:1.1 drop gears giving rear diff ratio of 3.54 but I have changed the tail cone to one with 1:1 drop gears giving a rear diff ratio of 3.9 so always better to get diff and box at the same time especially when dealing with the less common boxes.


Hi Arch,

My box is a TY752VB3EA, RA box I believe, or so google tells me. The replacement is a TY752VB4AA, again checking online I believe its a 1996 STI box and I have the matching diff.

Cheers to you.and Adam for the help. Defo would come a cropper if I didn't ask and matched my diff to the new box... Really don't fancy taking it apart again.

Paul
your car will accelerate better with the 4aa box that's a close ratio one if you don't use it give me a shout
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