Question on GS400 3.26 rear diff in a gte swapped auto SC... - Club Lexus Forums


Question on GS400 3.26 rear diff in a gte swapped auto SC...

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Old 08-10-14, 04:34 PM   #1
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Default Question on GS400 3.26 rear diff in a gte swapped auto SC...

Hey guys, I'm hoping someone has done this swap already so I can get some insight.

I have a 95 gte swapped SC400 with a built boostlogic auto tranny. Now that the bugs are kinda worked out on the car I can really get on it. I noticed that highway rpms are kinda high at 70-75. I'm seeing about 3100 - 3300 rpms or so.
Was thinking about puttin in a 3.26 rear which I know the pumpkins bolt up. This will give me some more gear for highway racing and drag racing since I shouldn't be using O/D under full boost since it hurts the tranny.

Has anyone else done this swap in an auto SC?
I have seen ppl do the swap in a 6 spd car.

Thanks for the insight everyone.

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Old 08-11-14, 06:20 AM   #2
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3.77 or 3.54 gets my Vote, IMO 3.26 is too long specially on the auto.

Stock SC400 92-97 is 3.92, is that what you have now?
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Old 08-11-14, 06:35 AM   #3
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Ya I got a 3.92 rear. Single turbo S366, boostlogic trans with an aem v2.
On the highway or standing starts it just seems to run out of gear to fast esp when I can't really use overdrive under full boost since the trans can def be broken that way.
I was gonna go tt auto rear but I'm not really gaining all that much gear back from 3.92 down to a 3.76.

This is my quandary.
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Old 08-11-14, 06:47 AM   #4
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3.54 would be perfect in that case.

Are you 100% sure it has a 3.92?
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Old 08-11-14, 07:02 AM   #5
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As far as I know the car was mechanically stock when I bought it which means it should have a 3.92 rear since it's a 95
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Old 08-11-14, 07:03 AM   #6
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Quote:
Originally Posted by 99SC42 View Post
3.54 would be perfect in that case.

Are you 100% sure it has a 3.92?
Which car had the 3.54 in it?
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Old 08-14-14, 08:15 AM   #7
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Quote:
Originally Posted by PaCowboy View Post
Which car had the 3.54 in it?
Im wondering the same thing

Have you thought about the LS400 3.62 gears? Seems like the balance point between the 3.26 and the 3.76.
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Old 08-14-14, 09:45 AM   #8
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Quote:
Originally Posted by turbodremz View Post
Im wondering the same thing

Have you thought about the LS400 3.62 gears? Seems like the balance point between the 3.26 and the 3.76.
I have thought about it. Might go that route. Or maybe just run a 28 inch tire at the track.
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Old 08-14-14, 10:26 AM   #9
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Im in a similar dilemma I'm assuming. Im running my car with the LS1/T56 with my stock 4.27 rear end, and although the acceleration is amazing, Im hitting 5th gear on the big end.

Im debating on gear ratio's, and also plan on jumping to a 28" tire. At the moment Im considering the 3.62 from the LS, but still need an LSD, so also toying with the fitting of a Ford 8.8 IRS with 3.55's and a locker.

I think the 3.26 may be too high for the auto at the track unless your going to 2-step from the line to keep your 60' acceptable. Im even pretty weary to use the 3.26 gears with the T56 in my car..so many choices, yet so limited.
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Old 08-14-14, 10:50 AM   #10
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Quote:
Originally Posted by turbodremz View Post
Im in a similar dilemma I'm assuming. Im running my car with the LS1/T56 with my stock 4.27 rear end, and although the acceleration is amazing, Im hitting 5th gear on the big end.

Im debating on gear ratio's, and also plan on jumping to a 28" tire. At the moment Im considering the 3.62 from the LS, but still need an LSD, so also toying with the fitting of a Ford 8.8 IRS with 3.55's and a locker.

I think the 3.26 may be too high for the auto at the track unless your going to 2-step from the line to keep your 60' acceptable. Im even pretty weary to use the 3.26 gears with the T56 in my car..so many choices, yet so limited.
Ya I'm thinking it might be. I would be 2 stepping it off the line at the track tho. But hell I would be potentially trapping 140 mph at like 7000 plus rpm with the stock rear. Which makes me a little uneasy.
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Old 08-14-14, 11:27 AM   #11
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I said 3.54 because I was just talking to my friend with a 240sx and he needs the 3.54 out the Q45T...I stand corrected.

Yeah the older LS400 96-97
3.62 out of the LS400, I know 96-97 are , not sure about the rest of the older ones.
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Old 08-14-14, 03:32 PM   #12
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Quote:
Originally Posted by 99SC42 View Post
I said 3.54 because I was just talking to my friend with a 240sx and he needs the 3.54 out the Q45T...I stand corrected.

Yeah the older LS400 96-97
3.62 out of the LS400, I know 96-97 are , not sure about the rest of the older ones.
I wish we didn't have transplant gearsets out of the LS into our pumpkins. It would make this whole decision process easier.
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