Topic: 4.1 vs 4.7:1

[Hilux92]

Hi guys I just ordered 4.7:1 crawler gears for my 92 Hilux. I am just curious to find out if I am in 1st low with standard 2.28 now, where will the same ratio be with the 4.7:1 fitted. I am running 5.29s with 33's and a 2200 cc 4y engine.. Also any Idea what my top speed will be in 5th if it is advisable to run in lowrange? I am just concerned about sand and mud where speed is a bit of an issue.

[cheap sunglasses]

I think 3rd gear will get you closest to what you had with 2.28 low in 1st.

3rd gear will be 1.93 x 4.7 x 5.29 = 47.98559
1st gear is 3.93 x 2.28 x 5.29 = 47.400516

[cheap sunglasses]

5th gear low range will be equivilent to your hi-range 1st gear. So whatever you top speed in 1st gear is.

5th gear/low: 0.83 x 4.7 x 5.29 = 20.63629
1st gear/hi: 3.93 x 1 x 5.29 = 20.7897

[BigMike]

Hilux92,

When you say "1st low with standard 2.28" are you referring to "1st gear in standard 2.28 low range"?

If so, then here is the ratio break down of a Single T/Case, one with 2.28:1 and one with 4.70:1, using a W56 transmission and 5.29:1 axle gearing:

Gear	2.28:1	4.70:1 Marlin Crawler
1st (3.95:1)	48:1	98:1
2nd (2.14:1)	26:1	53:1
3rd (1.38:1)	17:1	34:1
4th (1.00:1)	12:1	25:1
5th (0.85:1)	10:1	21.1
rev (4.09:1)	49:1	102:1

So as you can see, your current 1st gear will be like your new 2nd gear, your current 2nd gear will be like your new 4th gear, and your current 3rd gear is just a bit higher than your new 5th gear.

So to get a good idea of what 5th gear with 4.70:1 gears will feel like, shift your truck into 3rd Gear Low Range and see how that feels. That will basically be your new 5th gear.

Here are the speed comparisons with (true) 35" tires with the above setup up held to 4500 RPM:

Gear	2.28:1	4.70:1 Marlin Crawler
1st (3.95:1)	10 MPH	5 MPH
2nd (2.14:1)	18	9
3rd (1.38:1)	28	14
4th (1.00:1)	39	19
5th (0.85:1)	47	22
rev (4.09:1)	10	5

(Calculations made with the Marlin Crawler Speed Calculator)

So again, the same relationships exist, with the close approximation of your current 3rd gear acting as a slightly-faster new 5th gear.

I hope this answers your question.

The beauty of only replacing the gearing in a t/case is that there are no driveline or shifter modifications as required with dualcase setup.
The horrible thing about only replacing the gearing in a t/case is that once you engage low range, you will be stuck in Really-Really-Low-Range. You loose the factory range. This of course is sustained in a dualcase setup as you can simply engage just one low range lever if desired.

I know there exist some sand and mud situations that would require speeds in excess of 20 MPH (32 KPH), but I find that in the snow, I always have the greatest success with my 4.70:1 low range in 2nd and 3rd gear with 37" tires. Works like a charm.

Regards,
BigMike

[BigMike]

5th gear low range will be equivilent to your hi-range 1st gear. So whatever you top speed in 1st gear is.

Ahhh good observation.

[cheap sunglasses]

Ohh I must've been looking at the wrong tansmission's gears. Go with mikey's numbers.

[BigMike]

Ohh I must've been looking at the wrong tansmission's gears. Go with mikey's numbers.

You've got 3rd gear as 1.93:1 when its supposed to be 1.38:1

[Hilux92 [OP]]

Thanks guys. And it all started with a rear locker and 31's. How do I post pics of my Hilux?

[cheap sunglasses]

Thanks guys. And it all started with a rear locker and 31's. How do I post pics of my Hilux?

Hit preview your post and theres a button (under the italics button) to insert an image. You will need to host the image somewhere, I recommend www.photobucket.com, it's free.

You've got 3rd gear as 1.93:1 when its supposed to be 1.38:1

Yeah I was looking at R-series trannies. Only numbers I could find at the time.

[BigMike]

Hit preview your post and theres a button (under the italics button) to insert an image.

You'll first need to click on the "Additional Options..." link to expose this button.