LT1 and LS1 T56 differences
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Teching In
Joined: Jun 2005
Posts: 23
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From: Lexington, KY
LT1 and LS1 T56 differences I know the input shaft is different on them but what else would I have to do to make an LS1 T56 work with my LT1... Im doin a full swap from auto to 6 speed
yes there is a difference. u need a different bellhousing, and possibly a different shaft.
the lt1 t56s were built by borg warner, and they were strong as hell. then when ls1s came in the game, the t56 was sold to tremac. so now the mexicans build our trannys outa paper.
the lt1 t56s were built by borg warner, and they were strong as hell. then when ls1s came in the game, the t56 was sold to tremac. so now the mexicans build our trannys outa paper.
yah Turbo needs to stuff paper in his mouth so he doesn'y spew more misinfo. The LS1/ T56 application started at Borg Warner( '98 model year begins in August of '97). The sale of the Borg Warner trans assets / Tremec start of production T56s completed for production '99 model year AFTER January 99. Ther was a "mix" of Tremec/ BW T56s for99. The casting labels( BW) were changed after that. So you could have a Tremec T56 with BW casting labels. On later units it was even possible to have both Tremec and BW labels on the same trans.
Its a little ironic what Turbo said: BW made T56s with paper blocker rings - It was Tremec that got the carbon-particle blocker rings into T56s and avalable to "upgrade" older units.
Its a little ironic what Turbo said: BW made T56s with paper blocker rings - It was Tremec that got the carbon-particle blocker rings into T56s and avalable to "upgrade" older units.
I've seen LT1 T56's fragged just like LS1 T56's - strength difference? Hah. The only subtle differences (other than what jessman mentioned) I've seen between the two is that the LT1 has a 2-piece selector plate thing (I don't know what it's called, but it rides on the shifter shaft and it slides around the selector plate). The LS1 is 1 piece. And I've seen LT1 trannies without the rubber bumper that's just inside the driveshaft socket. These are very minor cosmetic internal differences. Calhoon got it right... my 98 came with a "Borg Warner" labeled T56 as well... and was showing mainshaft wear on the 5-6 driven gear at 50k miles.
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Teching In
Joined: Feb 2006
Posts: 43
Likes: 0
From: baltimore MD
Camaroholic...That little lever your talking about is called a front offset lever and it rides in the shift guide plate. Just in case you really wanted that useless bit of info 
. I had no Idea the ls1 version was one peice! I never had an ls1 version open. My lt1 t56 has a rubber slip yoke bumper.Ironically I have no Idea what the actual name for that is! Allthough it could have been install on a previous refresh.
. I had no Idea the ls1 version was one peice! I never had an ls1 version open. My lt1 t56 has a rubber slip yoke bumper.Ironically I have no Idea what the actual name for that is! Allthough it could have been install on a previous refresh. What you are calling a rubber yoke bumper is not. If you are referencing the the round rubber "donut" that has a molded spline( matching the output spline) on the inside, it is a shipping seal. The trans is shipped to the assembly plant pre-filled with oil. That seal is placed in th rear lip seal where the yoke will later reside. When the yoke is first incerted in the trans, the rubber seal is pushed forward on the shaft and has no further function for the life of the trans. Missing one is an indication the box has been appart before. In fact it is possible to have two of these if the unit was a factory audit.
The two -piece offset lever was the original design . The top rail still has the 2nd roll pin hole even though only a one -piece part is now used.( another piece of useless info. I suppose)
The two -piece offset lever was the original design . The top rail still has the 2nd roll pin hole even though only a one -piece part is now used.( another piece of useless info. I suppose)
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Joined: Mar 2024
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yah Turbo needs to stuff paper in his mouth so he doesn'y spew more misinfo. The LS1/ T56 application started at Borg Warner( '98 model year begins in August of '97). The sale of the Borg Warner trans assets / Tremec start of production T56s completed for production '99 model year AFTER January 99. Ther was a "mix" of Tremec/ BW T56s for99. The casting labels( BW) were changed after that. So you could have a Tremec T56 with BW casting labels. On later units it was even possible to have both Tremec and BW labels on the same trans.
Its a little ironic what Turbo said: BW made T56s with paper blocker rings - It was Tremec that got the carbon-particle blocker rings into T56s and avalable to "upgrade" older units.
Its a little ironic what Turbo said: BW made T56s with paper blocker rings - It was Tremec that got the carbon-particle blocker rings into T56s and avalable to "upgrade" older units.
my fear is this was unknowingly bad fluid to use back in 2000 and people have gotten more educated since.
i have people tell me to use what gm suggested when they stopped making dex three and that’s some kinda partially synthetic 70-80w ****.
most things just point to atf 3. Im more lost now then when I started.
I've seen LT1 T56's fragged just like LS1 T56's - strength difference? Hah. The only subtle differences (other than what jessman mentioned) I've seen between the two is that the LT1 has a 2-piece selector plate thing (I don't know what it's called, but it rides on the shifter shaft and it slides around the selector plate). The LS1 is 1 piece. And I've seen LT1 trannies without the rubber bumper that's just inside the driveshaft socket. These are very minor cosmetic internal differences. Calhoon got it right... my 98 came with a "Borg Warner" labeled T56 as well... and was showing mainshaft wear on the 5-6 driven gear at 50k miles.
Camaroholic...That little lever your talking about is called a front offset lever and it rides in the shift guide plate. Just in case you really wanted that useless bit of info . I had no Idea the ls1 version was one peice! I never had an ls1 version open. My lt1 t56 has a rubber slip yoke bumper.Ironically I have no Idea what the actual name for that is! Allthough it could have been install on a previous refresh.
. I had no Idea the ls1 version was one peice! I never had an ls1 version open. My lt1 t56 has a rubber slip yoke bumper.Ironically I have no Idea what the actual name for that is! Allthough it could have been install on a previous refresh.Yup that LT1 part had two pieces and some in the LS T56's, I've seen a couple. Most of the LS T56's are that single powdered metal piece. I've got a few in my parts bucket.
I tossed the second one for the Skip Shift out and kept the primary one for the Guide Plate when I built my T56 for my SS. I put a plug in where the Skip Shift goes too.
Last edited by the_merv; Jul 7, 2024 at 07:05 PM.
Those people don't know what they are talking about, Dex III ATF is 10W fluid. You put that 70-80W in there, which is not the replacement because it's Dex VI, it'll be like syrup compared to Dex III. Do not listen to them people.
Last edited by the_merv; Jun 29, 2024 at 06:21 PM.
Fluid is a much debated subject but supposedly the hottest fluid out (pun intended) is from Schaeffer's.
https://www.schaefferoil.com/204-atf-supreme.html
I ran Redline D4 in all of my T56's but they say that it is hard on the blocker rings... never caused me any issues. New transmissions or rebuilt ones just use the cheapest non synthetic DexronIII you can find and after 1000 miles of break in or so... dump it for something like Schaeffer's.
To swap from LS style to LT you need front bearing plate (midplate), input shaft, and bellhousing which will be well over $1K in parts if not more. It would be better to simply buy an LT style T56 that is rebuilt preferably... otherwise you are buying a 27+ year old transmission that most likely needs a rebuild. At that point you should just buy a new T56 Magnum F ($3550) then then you need a quicktime LT style bellhousing ($850). The swap isn't cheap that is for sure.
https://www.schaefferoil.com/204-atf-supreme.html
I ran Redline D4 in all of my T56's but they say that it is hard on the blocker rings... never caused me any issues. New transmissions or rebuilt ones just use the cheapest non synthetic DexronIII you can find and after 1000 miles of break in or so... dump it for something like Schaeffer's.
To swap from LS style to LT you need front bearing plate (midplate), input shaft, and bellhousing which will be well over $1K in parts if not more. It would be better to simply buy an LT style T56 that is rebuilt preferably... otherwise you are buying a 27+ year old transmission that most likely needs a rebuild. At that point you should just buy a new T56 Magnum F ($3550) then then you need a quicktime LT style bellhousing ($850). The swap isn't cheap that is for sure.
That brings up a good point. Given this thread is from 2006, nowadays if anyone for some reason needed to convert an LS T56 to LT type, sell the LS T56 for what they are worth and buy an LT T56. You'll have money left over to rebuild it.
