T56 Magnum Gear Ratios

[vdiaz133]

I have a 1998 C1500, extended cab that will soon be swapped with a 5.7 LS6. I am also doing a T56 conversion and have narrowed it down the to close ratio and the hybrid ratio transmissions. My question is should I go with the close ratio T56 or the hybrid ratio T56? I have used the Tremec gear ratio calculator but can't decide between these two.

My truck will have a stock LS6, 99.9% daily / street driver with a 14 bolt 3.73 gears and with stock 28.88" tires or 30.1" diameter tires. (235 75 R15=28.88) (295 65 R15=30.1)
I do plan on a mild upgrade in the future like intake, cam, and headers. I'm guessing that due to the weight of the truck I should go with the 2.97 but I want some legit recommendations.

close ratio T-56 (TUET11009) has the following gears 2.66 1.78 1.30 1.00 .80 .63
Hybrid ratio T-56 (TUET16885) has the following gears 2.97 2.10 1.46 1.00 .80 .63

 

[Supercharged111]

Man that is so weird the 5/6 is the same, on the T56 when you compare those gear sets the 2.97 trans gets a shorter 5/6 with the same gears because the input and counter are geared differently. I have an LS6 and 2.97 T56 in my C5 Z06 with 26" tires and a factory 3.42. I think a 3.73 would be a better match for me, or a 3.90 with a 2.66 trans. All that to say, I don't think your 3.73 will cut it either way. The 2.97 gives you better punch off the line without sacrificing cruising RPM like a rear gear change does. But in this case I think you should do a 3.90 or 4.10 with the 2.97 with the truck being as heavy as it is.

 

[vdiaz133]

This TUET16885 is somewhat of a newer transmission from TREMEC. I read somewhere that it's replacing the 2.97 / .50, hence a hybrid. I do agree that because of the weight, the 2.97 would probably be better. I'll have to see how it performs with the 3.73 before I start changing the rear.

 

[miroslav]

Did you ever complete this swap? I am starting this same conversion with my 97 and was also looking at the TUET16885. How do you like it?

 

[vdiaz133]

Did you ever complete this swap? I am starting this same conversion with my 97 and was also looking at the TUET16885. How do you like it?

I know this post is about a year old but i just now started the swap. I have spent the last year collecting parts. I just pulled the old engine and tranny out last week and currently starting the fitment phase. With all the other projects i have around the home, i can only work on it a little at a

 

[miroslav]

Nice clean truck! I wish mine was that clean.

I get it, I started collecting parts for my swap a while ago. Still have not gotten the trans yet, though... I decided to do an EFI Connection 24X swap on my original small block, along with the manual trans swap.

Please keep us updated on your progress. would love to see it.