My new transmission for review

[wolffcub]

Was using a 3 speed on my truck last year but with no OD. It was singing around 3200rpm to just do a bit over 60mph. I got a fairly recently rebuilt t-5 that is from a 85 s-10 with tag number 146. The 150 tag is listed as having ratios of 1st. 4.03 2nd. 2.37 3rd. 1.49 4th 1.00 5th 0.76. Currently have a 3.73 ratio rear end installed.

Attached are a few sheets I printed with different T-5 transmission tag numbers. I currently own the tag #146 but can also get my hands on tag number 072 and swap its guts into the s-10 t-5. What you guys think of the different ratios and what t-5 I have currently purchased ?

Using a 1955 235 with some goodies installed.

Tag #146




Tag #150




Tag #072

[wolffcub]

Oh and my current 3 speed setup

[octanejunkie]

I like the t-5 #146 ratios, you'll really get the truck moving quickly with that 4:1 1st gear and still be around 2500 at 65 MPH in 5th (not even Sammy Hagar drives 55)

You could use the #150 gearset also, which has a lower 5th gear ratio, but you already have the deeper gearing in the 146. I say run it!

But in all honesty, depending on the cam you are running and where you are making the best torque - you might want to look at the big picture to decide which gearing to run.

[1project2many]

Does your truck tow or carry anything heavy? Do you do a lot of city cruising or mostly highway driving? Are there more hills in your region or is it fairly flat? Do you like to shift?

The 1-2 split forces you to run to peak hp at 3800 or so then takes you well below peak torque on the shift while the 2-3 split. I'm not sure how much the head flow improvements help but the basic curve is the same so you might always feel like the 1-2 is lacking. And if you're in town or like to cruise light to light you'll either be shifting frequently like an old dump truck (1-2 @12-15 mph, 2-3 @22-25 mph, then 3-2 as approaching the light and clutch in to coast remaining distance) or be forced to leave the trans in gear and listen to the engine at higher rpm. The 146 gearset is going to feel most like adding an extra gear to your current trans.

If your truck doesn't tow much weight and is mainly used for cruising and trips to the drive-in and relaxing then I think 150 is a better match. The 072 will work but is going to be the most noticeable change. If you've ever driven a car with a close ratio transmission that's what the 072 will provide compared to the 146 or your current transmission.

[wolffcub]

The truck will never tow or move anything. Mostly city but a fast drive at highway speeds to get to work in the mornings. I was thinking about changing the rear ratio to the 3.42 offered for the GM 7.625" rear end i have. I also see a listing for one 3.55 ratio setup but i need to confirm the exact details of my rear end to see if that one will fit it properly.

Thoughts on the #146 t-5 now combined with a 3.42 rear ratio?

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[curmudgeon]

Wow, you really have given this a lot of thought. The T-5 is a good choice for the 235, since the hp is close to the s-10 2.2 liter engine and was also mated to the 3.42 rear. I have a #193 T-5 that I am planning to put behind a 6-cyl, but I think the low 1st gear, 4.03 leaves too much of a gap for the 1-2 shift. (drive a stock s-10 with the 2.2 liter) I think putting the Camaro T-5 gears, 2.95, 1.95, 1.34, 1.00, 0.73(?) into the s-10 T-5 tailshaft housing (for the more forward shifter position) with the 3.42, rear is the way to go.

[wolffcub]

Guess what im really after is opinions on the ratios of the #146 I just bought if i used it with my current rear end and tire sizes. I was using toms chart but it has conflicting info. I'm assuming he is using the stock tire size that i think comes in at 28" tall unlike my 25" tall ones. His A- rating has a first ratio of 14.02, the B+ has a first ratio 14.3. His other tech article on his site says a first ratio of 12 is desired, 10 requires slipping and 15 is going to get annoying. Currently my first ratio is 10.6 with the 3 speed but changing to the t-5 #146 will put me at 15.03. The truck does not have that much of an issue now taking off because I am sure the smaller dia tires are helping me out. I am assuming a 10:1 ratio for first as tom notes is probably an issue for taller tires.

I chew thru the gears so fast as it is now im in third as i just drive down the street.

Granted i can just stuff the t-5 in the truck but im trying to get a proper handle on this prior to the install so i can make changes to the ratios now and not have to drop the trans again later.

[curmudgeon]

A 15.03 1st is very low, and with 25" tires, on the way to being a "stump pullin" ratio. You mentioned that even with your current set-up you are geared low enough that you are in 3rd just to get down the street.

By way of comparision, since I live in Silicon Valley, Califorinia, I've tried to gear my ratios high so I don't get run off the freeway going "only" 70 mph. I run a 4-speed Saginaw with my 6 cyl, 3.11 1st with a 3.08 rear, the 9.6 first ratio, just enough to get off with 27" tires

The wide range of the #143 will give you a 13.7 1st and a 2.6 5th with the 3.42, more than low enough to take off and still able to run 70+ mph comfortably. (although you're not going to win any drag races with this set up).

[wolffcub]

I took 3 of my graph charts from above and marked them up a bit with some more info.

I don't think i mentioned that the T-5 i already bought with the #146 tag i only got for $50. Its in perfect shape and needs no servicing. I would like to stick with it if possible and maybe take in to consideration changing out the rear end ratio to possibly a 3.43 to help things out. A rear end kit is only $180 ish and im ok with that because i don't think i will find a tranny around here for near $50 again lol. Other used ones are selling between $850-$1200 with a different ratio but the wrong housing. I can always visit that idea later.
Also I am in Canada so im going to start talking in kph and marking my graphs in such. Basic speeds posted on my travels are 30,50,60,80,100,110. 90% of my driving is the 30 to 80 range. My engine torque curve is in the 1800-2200 area with the stock cam. Thinking about changing that out possibly this year or next so that rpm range will move up altogether a bit.

Chart with the current 3 speed and 3.73 rear ratio. You can see here when doing 30kph im either at 2800rpm in first or 1500ish in second. 50km im at 2800rpm in second or 1600ish in third. 60km is 1800ish rpm, 80km is 2500rpm,100km is 3200ish rpm.



Chart with the T-5 #146 speed and 3.73 rear ratio.



Chart with the T-5 #146 speed and 3.42 rear ratio.

[curmudgeon]

I spent more than $50 in gas to pick up my T-5. Peak torque for 235's is just over 2000 rpm and max hp at 3200 rpm so the #146 with the 3.42 will put you in the engine's torque sweet spot for highway cruising.

Have you figured out which clutch disc/pressure plate set-up you are going to use?

[wolffcub]

Originally Posted by curmudgeon

I spent more than $50 in gas to pick up my T-5. Peak torque for 235's is just over 2000 rpm and max hp at 3200 rpm so the #146 with the 3.42 will put you in the engine's torque sweet spot for highway cruising.

Have you figured out which clutch disc/pressure plate set-up you are going to use?

I was hoping to reuse the existing pressure plate and just get a new disk to suit the spline count on the t-5. My current pad and pressure plate were rebuilt and only have about 1000miles on them. I read that people are just using a new 10" dia disk. from a s-10. Others are using a 11" from a astro van. Im not sure what my current disk size is as my truck was originally a 3/4 ton then i moved everything onto a 1/2ton chassis.

[NEWFISHER]

I'm running the 146 with a 3:42 ratio 1955 rear in my 1946 Burb with a 235 stock--no upgrades. Running 225/75/15 tires and it works GREAT! I also used the Jeep input shaft and retained all of my 235 clutch parts as they were new. $80 for a Jeep shaft shipped was a no brainer.


Here's a thread I started when I did the swap that has some valuable info in it.
http://67-72chevytrucks.com/vboard/s...d.php?t=644565

[wolffcub]

Originally Posted by NEWFISHER

I'm running the 146 with a 3:42 ratio 1955 rear in my 1946 Burb with a 235 stock--no upgrades. Running 225/75/15 tires and it works GREAT! I also used the Jeep input shaft and retained all of my 235 clutch parts as they were new. $80 for a Jeep shaft shipped was a no brainer.


Here's a thread I started when I did the swap that has some valuable info in it.
http://67-72chevytrucks.com/vboard/s...d.php?t=644565

I can kiss you Fisher. I hope you thread has a part number for that shaft as that is something i will do for sure now.

[wolffcub]

Originally Posted by NEWFISHER

I'm running the 146 with a 3:42 ratio 1955 rear in my 1946 Burb with a 235 stock--no upgrades. Running 225/75/15 tires and it works GREAT! I also used the Jeep input shaft and retained all of my 235 clutch parts as they were new. $80 for a Jeep shaft shipped was a no brainer.


Here's a thread I started when I did the swap that has some valuable info in it.
http://67-72chevytrucks.com/vboard/s...d.php?t=644565

What is the actual transmission tag number on your setup?

[tinyjaime]

Where can i get a copy of that spreadsheet in excel form. I have some numbers i would like to run. That sheet is a good sums it all in one place.

[wolffcub]

Originally Posted by tinyjaime

Where can i get a copy of that spreadsheet in excel form. I have some numbers i would like to run. That sheet is a good sums it all in one place.

First one here is the same one i used in my above posts.

http://www.12bolt.com/gearing_calculator

I also like this one as you can overlap 2 options at the same time.

http://www.teammfactory.com/gear-calculator

[tinyjaime]

yup pretty cool I just ran mine I am running the similar set up except for the 0.72 final gear

thanks