how do you determine the gear ratios

[mikie_1980]

i have a 1980 f-150 4x4 its got the 4 speed with granny low and im just wondering what the gear ratio is

 

[DNFXDLI]

I fairly sure if you have a T18 the ratio for first is 6.32:1 and if it is a NP435 is is 6.69:1

 

[Beach66Bum]

another Gen.7 owner
the T-18 is fully synchronized in second to fourth, except first and reverse.

first gear: 6.32
second gear: 3.09
third gear: 1.69
forth gear: 1.00

 

[5.0Flareside]

Trans or rear axle?!?

 

[fatherdoug]

I fairly sure if you have a T18 the ratio for first is 6.32:1 and if it is a NP435 is is 6.69:1

Wow! I didn't realize that first gear on a 4 speed was that low. That's the only thing I miss about a 4 speed.

 

[Alvin in AZ]

I fairly sure if you have a T18 the ratio for first is 6.32:1 and if it is a NP435 is is 6.69:1

x2

Gear ratios...
1st 2nd 3rd 4th 5th -R-
T18 =========== 6.32 3.09 1.69 1.00 === r7.44
ZF M5OD-HD ==== 5.72 2.94 1.61 1.00 0.76 r5.24 <--- 1st and especially reverse is a little bit too high IMO
Mazda M5OD-R2 = 3.91 2.24 1.49 1.00 0.80 r3.39
NP435 ========= 6.69 3.34 1.74 1.00 === r8.26 <--- check out NP435's reverse
E4OD =========. 2.71 1.53 1.00 === 0.71 r2.18
Clark282V ====== 6.99 4.09 2.17 1.17 1.00 r5.89
NV 4500 ======= 5.61 3.04 1.67 1.00 0.73 r5.61
T19 = http://www.novak-adapt.com/images/graphics/t19_specs_gasket.gif

 

[SuperCab]

Trans or rear axle?!?

That's what I was gonna ask...

Sent from my iPhone using Forum Runner

 

[DNFXDLI]

Trans or rear axle?!?

That's what I was gonna ask...

Sent from my iPhone using Forum Runner

I just assumed the 1st trans ratio...but good question.
If it's rear axle and it is original, I'd look at the jamb sticker..if not, chalk the wheel at the bottom and chalk the driveshaft on the yolk and diff housing...count how many times the driveshaft turns to 1 wheel rotation..that should give you a rough idea...barring that, pull the cover and count the ring and pinion teeth and divide.

 

[5.0Flareside]

for rear axle ratio...

 

[Alvin in AZ]

8.8" (Visteon) tag...

Top two are Ford-9-inch tags...

...bottom two are T18 tags.

Alvin in AZ

 

[mikie_1980]

The rear axle

 

[Beach66Bum]

see post #9 from Chris in this thread, he has a great video for you.

 

[mikie_1980]

Ok thanks I appreciate it

 

[5.0Flareside]

Don't forget to like favorite subscribe!!!!!

#youtubemoney

 

[fatherdoug]

Don't forget to like favorite subscribe!!!!!

#youtubemoney

Good video, Chris. But you really should have a jackstand under that axle if you're rolling around under the truck.