PDA

View Full Version : Lt1 T56 Gear ratios



BigBlockOlds
08-15-2005, 07:03 PM
I bought a Weir Hot Rod bellhousing kit that will allow me to bolt an LT1 style T-56 behind my 455 Olds.

My question is regarding the gear ratios for the LT1 T56. I know the '93 trans had different ratios than the later versions but are there any other years that may have been different? Do they all have the .5 6th gear?

Are there any numbers or tags on the transmissions that will give me this information? Or what year/model car should I ask for at the junkyard?

Thanks for the help!

chicane67
08-15-2005, 08:24 PM
2.97:1, 2.07:1, 1.43:1, 1.00:1, 0.80:1, 0.62:1 forward, and 3.28:1 reverse.

This (http://www.5speedtransmissions.com/t56_early_gm.html) link will provide you more information.

BigBlockOlds
08-16-2005, 02:36 AM
According to that link it says the '93-'97 T56 (at least the one's they sell) have the 2.66, 1.78, 1.30, 1.00, .74, .50.

If I get a used trans that needs to be gone through or rebuilt, I assume I can just buy the gear ratio(s) that I want and have them installed correct?

I guess another question would be what rear gears would you run with each different transmission gear ratios? I'd like to keep my cruise rpm @ or below 2000 rpm at 65mph. Rear tire diameter is 25.7".

Thanks for the help,

Mkelcy
08-16-2005, 09:23 AM
According to that link it says the '93-'97 T56 (at least the one's they sell) have the 2.66, 1.78, 1.30, 1.00, .74, .50.

For your purposes there are two LT1 T-56's: those with the gear ratios Chicane posted and those you listed above.


If I get a used trans that needs to be gone through or rebuilt, I assume I can just buy the gear ratio(s) that I want and have them installed correct?

I'm not sure you can. Tremec seems to have roguhly two sets of ratios from first to sixth. I don't know that you can mix and match which ratios you want in a particular box. Take a look at this link for more info. http://www.ttcautomotive.com/English/products/T-56.asp#Car


I guess another question would be what rear gears would you run with each different transmission gear ratios? I'd like to keep my cruise rpm @ or below 2000 rpm at 65mph. Rear tire diameter is 25.7".

I have a 2.97 first gear T-56 with 4.11's and roughly 26" rear tires and turn about 2300rpm at 65.

BLUE72CAMARO
08-16-2005, 10:31 AM
You can I.D. the tranny by the aluminum tag hanging on one of the tailshaft bolts. As far as 93 only having the 2.97:1, 2.07:1, 1.43:1, 1.00:1, 0.80:1, 0.62:1 forward, and 3.28:1 reverse ratio is not true. I have a 93 t-56 that has the .5:1 6th gear. But it also is an odd ball on the part number compared to what they reference for f-body transmissions.

white79bu
08-16-2005, 11:40 AM
I have a 95 t56 in my 79 Malibu with 4.10 gears and 255/45/17 tire. It run's around 1800 rpm at 65 mph.

Ralph LoGrasso
08-16-2005, 01:43 PM
According to that link it says the '93-'97 T56 (at least the one's they sell) have the 2.66, 1.78, 1.30, 1.00, .74, .50.

If I get a used trans that needs to be gone through or rebuilt, I assume I can just buy the gear ratio(s) that I want and have them installed correct?

I guess another question would be what rear gears would you run with each different transmission gear ratios? I'd like to keep my cruise rpm @ or below 2000 rpm at 65mph. Rear tire diameter is 25.7".

Thanks for the help,


With the stock rear tires on my '01 SS (25.7" diamater), I turned 1500rpm at exactly 66mph in 6th. This is with 3:42 rear gears and an LS1 T-56. I'm not sure if 6th gear is .50 or .62. Use one of the calculators out there to dial in the perfect gear for your needs. I think there is a link to a bunch of them in the outhouse.