Older pickups -- low gear?

[Raven]

One last place I worked at had a 70's chevy 1-ton pickup with a three speed manual transmission. It also had the L gear (low). Someone I met once said his dad's pickup on the farm also had the Low gear (lower than 1st) because it was cheaper than 4WD -- poor mans four wheel drive. (He also said his tractor was a two-stroke diesel with supercharger. This dates back to the 40's or 50's.)

Anybody have the ratios for those transmissions? You don't see them much these days, and even then when you can shift into LOW on an automatic transmission (like our '05 Tundra) it's just 1st gear anyways.

Also, experiences of using those gears, and whether they're worth it. Of course if you have a switchable high-low transfer case then it's pointless, but then you have 4WD right there.

 

[Chris142]

Usually in the 6 to 7xx range. Good for pulling a boat out of a lake or getting a horse trailer moving instead of smoking the clutch. My 4x4 ford has a "granny" gear and a low range in the transfercase. It will go about 2 mph @3000 rpm

 

[Chris142]

http://www.novak-adapt.com/knowledge/np435.htm

 

[wirelessF]

The ZF S6-650 in my 04 F250 has an L gear. On the floor it looks like a 6 speed trans but it's L,R,1,2,3,4,5. L gear ratio is 5.71 vs 1st gear ratio is 3.31. L and R is also on the same leg which makes for convenient vehicle rocking if stuck.

 

[Chris142]

http://cjford.stormloader.com/Tech/mantransinfo1.htm

 

[SwampSurvivor]

Granny gear. It's so you can take off with a heavy load without burning up the clutch.

I miss driving a vehicle with a granny gear. Seems weird having to give gas to take off from a stoplight.

 

[Stewart Fan]

The 1st gear in my '07 Ram 3500 with the 5.9 Cummins was 6.29:1

It was low enough to be basically useless. I never used 1st empty. The truck and my fifth wheel were 21,000lbs combined. Even at 21,000 combined I rarely used 1st.

 

[Zaedock]

I use first gear in my Wrangler all the time. The 7.05 first, combined with the t-case and axle gears make my Jeep drive slower than you can crawl.

 

[ecotourist]

My dad called it "Bull Low". Useful on a farm when you're hauling a load of wheat on loose soil.

Ecotourist

 

[cpayne5]

That old Chevy had a GM Muncie SM465 transmission. L is geared at 6.55:1.

My parents had a '78 Chevy C30 regular cab dually with a 454 and this transmission. It's what I grew up in. It was the first manual transmission I drove. I was 10, driving it around in the fields on our place.

My parents had horses and they used it towing horse trailers around the east coast.

 

[hattaresguy]

Unimogs have them for the PTO's.

 

[ls1mike]

My old 71 K5 had a granny low. Loved it for overloading.

 

[Smoky14]

Granny gear and first gear had no syncro so you had to double clutch to get in gear without grinding a pound. Good rig to learn how to drive when I was 14.

 

[SwampSurvivor]

Originally Posted By: Raven
(He also said his tractor was a two-stroke diesel with supercharger. This dates back to the 40's or 50's.)


2 and 3 cylinder detroit diesels on small tractors were pretty common. They require a roots blower to aspirate.

 

[Raven]

Right, thanks for those helpful answers! Would such a crawler gear be useful for rock-crawling, by any chance?

 

[supton]

Yes, it would avoid having to run crazy deep gearing in the diffs, which would then make for high rpm's on the highway. Not that you'd hear those rpm's, not with gnarly off-road tires, nor could you tell from your pocketbook, again from said gnarly tires; but many do like granny gearing for that purpose (slow going over obstacles).

 

[SwampSurvivor]

4.88 gears, 2.72:1 transfer case and 5:1 first gear ... some jeeps will crawl ... at a crawl.

Gear ratio is directly proportionate to broken axles, U-Joints, differentials. People will gear their Jeeps super low, put it in 4LO and 1st gear and bounce it off the rev limiter and dump the clutch with 35'' tires.

Things go bang quickly.

 

[jimbrewer]

Dad always called it "double low" on the 1970 Ford pu. had limited slip so it could go about anywhere. Its possible to have it on 4x4. Mine had a top speed of 6 mph in double low 4x4. Its used for rock crawling, stump pulling, that kind of thing. Not street driving, generally.

If I had manual truck, its something I would pay for.

 

[rslifkin]

Most newer manual 3/4 ton and 1 ton trucks still have a granny 1st. It's just the 1/2 tons that don't (although manual trucks are getting rare in all 3 types).

 

[SwampSurvivor]

The only manual trans you can buy in a 3/4 or 1 ton truck (or even half ton) is a dodge with a cummins.