5 spd in a 37 pickup with a 4.44 rearend.
 

What will my rpms be at 55mph? I'm running 15" radials. 6.75 R 15. Wondering if it will help. 5spd is a 1985 S-10. Thanks agian for the help, Jim. [email protected]

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

RPM equals MPH times the Transmission Gear Ratio times the Rear Axle Ratio times the constant 336 all divided by the Tire Diameter.

RPM = (MPH X TGR X RAR X 336)/TD

You know the tire diameter size you are using so you can look up the diameter.
You know the MPH you want the RPMs at, 55.
You need to determine the Overdrive gear ratio for your transmission.
You know the Rear Axle Ratio, 4.44.

So, RPM = (55 X TGR? X 4.44 X 336)/ TD?

I don't see a 6.75 tire, but a 6.70-15 radial is 28.24 inches.

Assuming a V6, the OD ratio of a 1985 S10 T5 should be 0.70 (think that should be 0.72)

RPM = (55 X 0.70 X 4.44 X 336) / 28.24
RPM = 2034 RPM

If my math is correct, 2034 RPM

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Wow. Thank you so much. The engine the t-5 came frome was a 1985 S-10 4 cylinder. Same ratio? Thanks again. Jim.

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Your tire size is right not mine sorry. Jim

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

You really need the tag number, but I can do a search. Looks like it could be an 0.86, if so the rpms would be: 2,499. Without the tag number it is difficult to be sure what OD ratio you have. I'm a Ford guy and only really know the Ford T5 numbers! :)

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

I'll get it tomorrow. Thank you, Jim.

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

I'm finding conflicting data just using year and engine type, the tag number would nail it down. The attached chart gives some of the tag numbers.

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

If that is indeed an S-10 trans, it's more than likely that the 1st gear ratio is going to be 4.03. I'd be more concerned that by combining that 1st gear ratio with a 4.44 rear end would just about make 1st gear useless. DD

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Yep, but can always drive it as a 3-speed with OD. :) I much prefer the Ford Cobra and later Chevy gearing (close-ratio), with a low rear axle gear.

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

I absolutely agree with the close-ratio derivatives. Even the EARLY Chevy and Ford gear sets had the 2.95 1st gear (close-ratio). DD

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Here is a handy calculator to figure RPMs. When I actually checked mine with a tachometer it was spot on with the calculator,

https://www.crawlpedia.com/rpm_gear_calculator.htm

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

These trannys are really simple units and different gears are available for first and such - you can try Ed Harnett in Maryland as he might be able to provide you with a decent gearset that would match your combo well. The tag would really tell the story but if there is no tag, and indeed the tag might not be correct, you can run through the gears and count the revolutions to come up with a good idea on what you have presently.


BTW, 55 mph at 2000 rpm isn't bad - your 5th gear ratio should be around 2500 at 75 MPH - that would give you plenty of power for the hills with that 4.44 rear gear I think.


Reagardless, have fun doing it - you will not regret it IMHO .....

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Got it in. Now to get rid of the vibration in the driveline. The shaft is balanced and U joints are okay. New slip yoke and bearing going in. LOVE that T-5.

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Are the angles and phasing correct between the transmission, driveshaft and rear axle?

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Checked with laser and it's right on. Reballanced driveshaft third time. Much better but still can feel it between 51 and 58mph. When below or above it's gone unless you push the clutch in and it really vibrates slowing down and disappears again at 25mph. What in heavens name is going on. I love this setup otherwise.

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Oh BTW. I a m using a gps for speedo accuracy. Still need to figure an new gear for tranny.

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Has the flywheel and clutch assembly been balanced?

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

Just think of the burn outs he can do in 1st, just light em up!!

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

A lot of times, you'll get that type vibration, when the tail shaft bearing is warn. The front yoke to tail shaft bearing.

Re: 5 spd in a 37 pickup with a 4.44 rearend.
 

New bearing in tail shaft, no difference.