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View Full Version : how do i drive this truck ???


P.Services
07-31-2007, 10:23 PM
let me start by saying if you just want to burn my goose on this one take it somewhere else, im looking for help not a fire storm



can some one who knows how walk me threw driving a 2spd rear end? its in a 1990 chevy kodiak with a 366 gas 5spd w/ 2spd rear do i go from low to high with the clutch in or out in gear or out of gear? and dose any one know the gear sequence 1L 1H 2L 2H 3L 4L 3H 4H 5L 5H i think

i know this is something that is very hard to explain to me in writing but any help will be appreciated thanks in advance !!:waving:

tthomass
07-31-2007, 10:48 PM
1L redline, lift off the gas and flip to 1H.......all up through 5H

Clutch is not needed for shifting. Use it until after 2nd......then once you are good you'll only need the clutch to start off.

*shifting without the clutch........keep your timing the same. Lift the gas and go to the next gear the same way and timing but just don't use the clutch. Once you learn the sweet spot you'll be golden. The stick will settle into the next gear once the rpm's drop. Also, you must have just finished excelerating as it won't want to come out of gear otherwise.

P.Services
07-31-2007, 11:03 PM
so i dont need to clutch at all between L AND H? to go to H i let RPMs drop and it will ingage and to go from H to L I incress RPMs right ? thanks

tthomass
07-31-2007, 11:39 PM
No clutch to shift UP.

So you're in 1 LOW. Redline the gear and at the same time you lift the gas flip to HIGH. Then redline again and go to 2 LOW.

Now, going from 1 HIGH to 2 LOW flip back from HIGH to LOW as you shift. Just to make things a little easier you may want to stick to using the clutch until you get the hang of LOW HIGH. So you would redline 1 HIGH, CLUTCH + FLIP to LOW and go into 2nd gear. Once you have the LOW HIGH down go ahead with not using the clutch........if all of this becomes a brain fart for you while driving.

Once you've got the hang of it.......its easy. Just think of learning to drive stick for the first time and getting 'smooth' with it.

Groh's Mows
08-01-2007, 01:43 AM
just to add to what has been said... I would not take the term redline literally, you just want to keep the engine operating between the peak torque and the peak horsepower. On a gas dedicted truck engine this occurs fairly low in the rpm band and you will learn to "feel the sweet spot" of the powerband just like the sweet spot shifting. I drove a nursery delivery route for about 2 years with an international 1600 gas v-8 5spd 2spd axle. Depending on your load, you can use the 2spd axle to get going and just use the high range once rolling on open roads. Just a little less shifting which is someting these old trucks will wear you out on.

Gravel Rat
08-01-2007, 03:25 AM
Just becarefull with the 2spd you can blow the range fork in the rear end. I wouldn't be making shifts on any hills with a loaded truck.

As the others said you will find where the truck pulls the best. The 366 is a gutless pig especially if its on propane.

Myself I don't drive two speed trucks I driven one once all the trucks I drive have 13spd road rangers.

Good Luck

Fatboy
08-01-2007, 09:25 AM
I'm trying to remember all the different trucks that I drove w/2sp axles, quite a few both gas and diesel. Tthomass is mostly wrong and if someone drove one of my trucks that way he would have found himself on the street in short order for abusing equipment.
Start in low axle/low gear and shift up through the transmission to 3rd or 4th before splitting the gears. Theres also one split that will actually result in a downshift in some of the trucks that I drove and is not used, 4th high to 5th low.
Most of the time I just got tired of splitting gears and would leave the axle in low until after getting into 5th in the transmission and then pulled the knob for high axle and releasing the throttle just enough to let the gears engage, then back on the throttle.
There should be a sticker in the cab explaining the shift sequence.
For splitting an upshift the button is down for low axle, at the correct speed pull the button up and slightly release the throttle to take the torque off the gears. When the axle shifts then reapply the throttle. Shift the trans to the next higher gear and just before engaging the clutch push the button down for low axle.
To go from high to low axle in the same trans gear don't release throttle but push button down at the same time as disengaging and re-engaging clutch. This removes the torque and brings the rpm up to match the road speed.

You have to practice.
Fatboy

tthomass
08-01-2007, 05:35 PM
If you want to go through all the gears......this is how it was done on the pig gassers at my previous company. Each truck is different and I shifted different depending on the load.

Redline does not = rev limiter.

Typically I did not split HIGH/LOW until 3rd gear. But again, if I've got 1000 perennials or 100 shrubs or that + a skid on a trailer depended upon how I shifted. If at all possible, I never messed with it unless it was really needed.

Fatboy
08-01-2007, 07:21 PM
The problem with turning a lot of rpm in the lower gears is that the axle will slam into gear as soon as you pull the button, good way to destroy the axle or break an axle shaft. Using the clutch to ease the shift will waste so much time that it's more work than it's worth.

One way to tell that a driver is inexperienced is that they tend to over speed the engine while accelerating through the gears. A lot of RPM gives them time to find the next gear.

When I think back about the worst trucks that I ever drove, right at the top of the list is a F model Mack cabover single axle tractor with a 5sp trans and 2sp rear. The frame had been lengthened and had a tag axle installed. It was ok on the road but it was easy to highside the drive axle in holes and RR tracks, not good with a 48,000# load in a 42' trailer. Most times I could get going by dumping the air bags on the tag but every once in a while I have to get help and always carried a chain.

Fatboy

SiteSolutions
08-01-2007, 10:35 PM
I've got a similar setup, a few years older. I don't split gears when lightly loaded, until maybe the top. I found out through practice that on my truck, 4H is almost exactly the same gear as 5L, so I might go up through 2,3,4 (1 is the "creeper" on mine) all on the L axle, then shift the axle to 4H by pulling up, clutching briefly until I hear/feel it change, then run out 4H and then shift to 5H. I have found that clutching the axle shifts lets it shift without putting so much strain on it. Definitely something to consider on these older beasts. Besides, with this set up, you really can't go much slower anyway. Clutching only takes a little effort and will hopefully extend the service life of a bunch of stuff I don't want to replace. If you drive this truck so often that clutching is wearing you out, then start saving for a newer one. If you're staying that busy, hopefully you can afford it.

Also, when downshifting the split axle, you have to not clutch so you can bump up the revs so the axle will go into the lower ratio.

My 5 spd is such a pain to shift that I often double clutch it. I can float gears just fine in an Eaton Road Ranger 8 spd, but all the 5 spds I have driven seem to resist being driven this way.

Just my opinion. I've driven them a bunch of different ways for other people, but this is how I treat my old dump truck.

twj721
08-01-2007, 10:42 PM
just depends if it is what they call a working 4th and 5th if it is then it 1 L H do this till 4th L then you go 5 L then back to 4 H then back to 5 H

SiteSolutions
08-01-2007, 10:56 PM
just depends if it is what they call a working 4th and 5th if it is then it 1 L H do this till 4th L then you go 5 L then back to 4 H then back to 5 H

Yeah, I have used the top two gears like that when loaded down. It's funny cause it shifts like you describe, from 5L to 4H, but the sticker on the visor reads out 4H to 5L! Guess you can't believe everything you read. In practice, 5L is so close to 4H that I usually just skip 5L unless I'm on a slight grade. (On real hills I can't even get near the top end of the tranny)

twj721
08-01-2007, 11:06 PM
check this old truck out on U tube http://www.youtube.com/watch?v=xAADEoJpTFQ be sure and turn volume up lol

twj721
08-01-2007, 11:07 PM
Yeah, I have used the top two gears like that when loaded down. It's funny cause it shifts like you describe, from 5L to 4H, but the sticker on the visor reads out 4H to 5L! Guess you can't believe everything you read. In practice, 5L is so close to 4H that I usually just skip 5L unless I'm on a slight grade. (On real hills I can't even get near the top end of the tranny)

the old GMC 366 with a working 4th and 5th really sound sweet when they are working

Gravel Rat
08-02-2007, 03:56 AM
I have watched that Tube video before. Its not easy running a 5+4 you can get lost in geardom. Shift the main box shift the aux box shift the main box shift the aux box. Todays trucks are a piece of cake to drive compared to yester year with gas pots 5 and 4 gearing or 5 and 2spd rear.

The big thing with 2spd rear axles is don't be rough with them they blow real easy. The gear that runs the range selector in the 2spd can grenade.

South Florida Lawns
08-04-2007, 10:13 PM
holy crap that looks complicated. I wouldn't even know where to Begin.

twj721
08-04-2007, 10:51 PM
simple easy as falling off a log as long as you don;t have some one sitting next to you that will rap your knucles when you miss a gear or scratch a gear OR LORD help if you get them hung up LOVE THE OLD TRUCKS they were real metal and very little plastic and sure no freaking computers

Gravel Rat
08-04-2007, 10:55 PM
The only thing with 5+4s is don't get lost in the gears. The A box is usually low-direct-high-over.

That guy on You Tube is using all the gears in the A box.

SiteSolutions
08-06-2007, 10:31 PM
I just test drove my 84 GMC at the mechanic's shop this afternoon. (I will have to wait till payday to pick it up, the bill was almost 3 grand) Holy Cow what a difference a little mechanic work makes. Well, okay, it was a LOT of work but that truck has never felt that good before. New carb, new header on one side, fixed leaking header on other side, new starter, completely new brakes on rear, new lights, rear end seals, adjusted clutch, and they put fluid in the tranny... which is what leads me to post in this thread: Now that I have had the clutch adjusted and there is proper fluid in the transmission, the gears actually float real nice! I figured I had better add that in light of my earlier comments on 5 x 2 setups being too stiff to float gears easy. I'll probably still double clutch it under load but nice to be able to save my knee a little bit when empty.

Fatboy
08-07-2007, 03:37 PM
And then there's the three speed rear axle....Fun.

FatBoy