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Old 08-04-2015, 12:34 PM   #1
Zener424
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Default Rear End Gear Ratio for T5 Transmission?

I installed a T5 transmission from a 1987 Chevy S10 in my Town Sedan. Overall I'm quite happy with it. However, 1st is very low. In fact I feel all the gears might benefit from a better rear end gear ratio but I'm not sure what gears would be best. I currently have a the stock 3.78 gears. I would appreciate any thoughts on this matter.
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Old 08-04-2015, 01:20 PM   #2
Rex_A_Lott
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Default Re: Rear End Gear Ratio for T5 Transmission?

A lot is going to depend on what you have for a motor. For a stock rearend you have a 3.54, a 3.27 and a 4.11 available, other than your 3.78.
In theory you can divide the ratios and find the reduction in RPM you will get for a given speed, but you eventually get to the point where the motor cant pull the taller gear. Good Luck
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Old 08-04-2015, 02:07 PM   #3
1931 flamingo
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Default Re: Rear End Gear Ratio for T5 Transmission?

I believe there are many diff tranny ratio's available also. You might try asking this on the HAMB or the EV8 forum. It may not be your rear end ratio.
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Old 08-04-2015, 02:09 PM   #4
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Default Re: Rear End Gear Ratio for T5 Transmission?

Here is a list of all the ratios http://www.britishv8.org/Articles/Bo...T5-ID-Tags.htm

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Old 08-05-2015, 06:27 AM   #5
Zener424
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Default Re: Rear End Gear Ratio for T5 Transmission?

Thanks to everyone for the feedback. I have a rebuilt, stock engine. I currently have a 3.78 rear. I have identified my transmission gear ratios from the chart:
3.39 3.50 2.14 1.39 1.00 0.78. The car runs fine, have had it up to 60 mph, no problem, but 1st is very low, 4th seems to be needed a bit early. With all this info., how do I proceed. Perhaps a 3.54 rear end ratio would be helpful? Or maybe just leave it alone?
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Old 08-05-2015, 07:06 AM   #6
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Default Re: Rear End Gear Ratio for T5 Transmission?

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How does the car feel in OD? If it does not feel like it needs another higher gear, I would leave it alone. Ron W
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Old 08-05-2015, 07:14 AM   #7
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Default Re: Rear End Gear Ratio for T5 Transmission?

Why did you change it in the first place ? Wayne
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Old 08-05-2015, 08:25 AM   #8
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Default Re: Rear End Gear Ratio for T5 Transmission?

well the t5 in my 4 banger 95 s10 your shifting every 10mph increase in speed. thats with the factory s10 ratio of 3.73.

you have a truck transmission which i feel is better in a model A due to its power to weight ratio. I dont think you would be happy if you had a t5 out of a camaro or something sporty.
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Old 08-05-2015, 08:39 AM   #9
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Default Re: Rear End Gear Ratio for T5 Transmission?

I have a banger with a t-5 . tried 3.54 but still to low . I just installed 3.27 hoping to help 1st gear ................ my t-5 is a 0.78 I believe .
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Old 08-05-2015, 10:25 AM   #10
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Default Re: Rear End Gear Ratio for T5 Transmission?

Quote:
but 1st is very low,
How does it work if'n you don't use 1st? Just start off in 2nd.
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Old 08-05-2015, 11:44 AM   #11
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Default Re: Rear End Gear Ratio for T5 Transmission?

Ron-5th gear is fine 60 -65 mph, and doesn't seem to want anything more.
As you said, maybe I'll just leave it. I'm guilty sometimes of seeking perfection.

V4F-please let me know how the 3.27 performs. When I look at the description of the 3.27 gears in the Model A vendor catalogs it always states: "must have a strong engine". What does that mean? Is a rebuilt stock engine, stock head strong enough?

katy-2nd is ok on perfectly flat ground, but the slightest incline and it's "boggy".
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Old 08-05-2015, 11:52 AM   #12
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Default Re: Rear End Gear Ratio for T5 Transmission?

I'm using the T-5 from a Chevy truck with a B engine equipped with a CRAGAR head, headers, etc. the rear end is 3:54. Add an F-100 steering box and yopu have the perfect touring car
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Old 08-05-2015, 04:02 PM   #13
31 Vicky
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Default Re: Rear End Gear Ratio for T5 Transmission?

T5 first gear of 2.95 is about ideal, just slightly taller than stock.

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Old 08-05-2015, 06:05 PM   #14
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Default Re: Rear End Gear Ratio for T5 Transmission?

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Originally Posted by 31 Vicky View Post
T5 first gear of 2.95 is about ideal, just slightly taller than stock. . . Dave
Zener424's T5 from an '87 S10 would probably be a NWC case. You can't swap either the 2.95 or 3.35 gearset into it. You would need to swap the case for a WC and modify the S10 tailstock oiler to fit up to the WC case. Then you would have to deal with the different input spline count and length. I believe the NWC/WC shifter forks are a bit different, too?

More of a HAMB question. There's lots there about T5's.
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Old 08-05-2015, 06:28 PM   #15
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Default Re: Rear End Gear Ratio for T5 Transmission?

Don't forget: tire size also makes a big difference!
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Old 08-06-2015, 04:46 AM   #16
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Default Re: Rear End Gear Ratio for T5 Transmission?

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Originally Posted by V4F View Post
I have a banger with a t-5 . tried 3.54 but still to low . I just installed 3.27 hoping to help 1st gear ................ my t-5 is a 0.78 I believe .
It might help the low first gear, but your going to kill 5th gear, unless you have a pretty stout engine
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Old 11-20-2020, 07:32 PM   #17
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Default Re: Rear End Gear Ratio for T5 Transmission?

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Originally Posted by MikeK View Post
[FONT="Comic Sans MS"][SIZE="3"][COLOR="DarkRed"]Zener424's T5 from an '87 S10 would probably be a NWC case. You can't swap either the 2.95 or 3.35 gearset into it. You would need to swap the case for a WC and modify the S10 tailstock oiler to fit up to the WC case.
Lots of "not-so-good" info here. '83 thru '87 Camaro V8 T5 (Non World Class-NWC) comes standard with the 2.95 gear set. That is what needs changing... the transmission gear set. You would have two choices. Find a NWC Camaro V8 trans (it must be the V8 trans...easily identified by the 26-spline input) at a swap meet. Your S-10 tail housing, the lid with shift rail and shifter will bolt right on to the Camaro case. You'll have to slightly modify the speedometer gear location.

OR.......

You can swap the NWC Camaro main shaft with the S-10 main shaft, assemble the trans normally using the Camaro gear set, and the speedo will work as is. The Camaro gears are completely interchangeable with the S-10 main shaft. Now, you have a great gear ratio (2.95 1st gear), including a close-ratio gear set that shifts wonderfully, and a .63 OD ratio. The ONLY reason you ever need anything "S-10" is for the tail shaft housing and shift lid which moves the shifter farther forward. The S-10 gear sets SUCK hugely!

But, then again, this is a five year old thread! DD
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Old 11-21-2020, 12:02 AM   #18
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Default Re: Rear End Gear Ratio for T5 Transmission?

When looking for a 5 speed trans. I wanted an s-10 because of the shifter location. A trans out of a 4-cyl has a low 1st gear and a not too tall 5th gear which is what I wanted. Could not find one in So Cal that was not over $800 (Hot Roders love these transmissions) Did find a very good trans out of a V6. Changed the diff. to 4.10. The low 1st is for parade use and a close to stock engine can pull 5th gear. Very happy with that combination.
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Old 11-21-2020, 01:19 AM   #19
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Default Re: Rear End Gear Ratio for T5 Transmission?

Quote:
Originally Posted by V8COOPMAN View Post
Find a NWC Camaro V8 trans (it must be the V8 trans...easily identified by the 26-spline input) at a swap meet. Your S-10 tail housing, the lid with shift rail and shifter will bolt right on to the Camaro case. You'll have to slightly modify the speedometer gear location.
I have this exact setup in my Model A coupe with the same 3.78 rear gear set and it's great. Luckily, you have the more expensive part of the puzzle (the S10 tailshaft) and Camaro boxes can be had cheap.
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Old 11-21-2020, 11:45 AM   #20
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Default Re: Rear End Gear Ratio for T5 Transmission?

My Vicky has an S-10 trans. w/the 4:1 1st gear and 26% OD and a 4.10 rear end. I normally start in 2nd gear and with the 26% OD, it is great on the highway. I do use first when starting on a hill, and when hill-climbing.
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