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i have a '72 GMC 7500 with a fuller 10 speed and it doesn't like shifting into any gear when i try to pick up speed on the road, but when i don't try to pick up speed, just shift it's fine what would the problem be. the truck only has 15 to 20K miles on it.

I'd be curious to know myself. I used to drive a '71 9500 with a 10-speed and never experienced any problems with it. Hopefully some of our trans experts will be jumping in to help. I'm sure that it goes without saying that you have checked the gear oil level.

i checked the gear oil and it was full then i drained out a quart and put in a quart of Lucas about a week ago and it didn't change anything. checked the oil again today it's still full and I'm still confused.

is this a recent problem or has it been on going gradually getting worse

47chevy6400,

Let me first say I don't know squat about a Fuller 10 speed. Having said that, I wonder if it isn't the transmission, but a clutch/pressure plate problem when it's depressed under load.


Stuart

Have you driven a Roadranger before?

For those who have not, They are not synchronized, so double clutching and or matching speeds is essential.
I prefer to not use the clutch once rolling and match speeds with the accelerator peddle, then slip it easily into gear.

Another problem you may have, is if it has a pull type clutch it should have a clutch brake. This brake will engage when the clutch is pushed all the way to the floor, and it will stop the input shaft and countershafts from turning. This is useful only when starting from a stop, say at a stop light out of gear clutch out, instead of pushing the clutch in and waiting for things to stop spinning so it will go in gear, you use the clutch brake and make them stop spinning, saves time.
If you depress the clutch all the way when driving/shifting, it will be very difficult to shift, as the clutch brake works and messes up your speed matching plans (double clutching).

I am by no means a professional at this, but I have driven several thousand miles with a Roadranger 10 speed, and worked on a few.
Grigg

try shifting without the clutch. as you let off the gas shift and as the engine is slowing down to about the speed of the next gear shift into the next gear...takes a bit...but old road rangers shift best without the clutch and learning your engine speed... in other words the diesel say wound out at 2200 or so...then drops down to 1800 or so for next gear....its hard to explain... have some old truck driver show you how to shift without the clutch... well except for starting like they said...its uhhhhhhhh sort of like driving and shifting a two speed rear end.... only the rpms have to be close....

Ditto on the above comments. A big rig clutch is for starting and stopping- - - - -once the vehicle is moving, stay off the clutch and just "float" the power, neither accelerating nor decelerating. The shifter will slip into neutral, and as the RPM drops, it will slip into the next gear without grinding. It will take several missed shifts before you get the hang of it, but once you get the moves dowm pat, shifts are much quicker and less stressful to the engine and trans than shifting by using the clutch.
Jerry

Just to add a little extra, I'm from the old school and always use the clutch. I can shift a Road Ranger actually smoother with the clutch than without. Every once in a while I would drive the truck without using the clutch and I wouldn't have any problems but really didn't like it.

The clutch with a brake is a new one to me. It seems like a truck having that kind of clutch needs to be shifted without the clutch. How new to the market is this type of clutch, as I have never heard of one. Is it's main purpose to prevent grinding when stopped and going from neutral to first?

Bill

all i know about the clutch is it looks like any other clutch just bigger. and are all fuller transmissions road rangers or is there another name? the only reason i said it was a fuller is because the shifter says it. i went and looked for a model # and found a plate that has two numbers one is 3820155 the other is 18827-F-1 I'm not sure which is the model number because the black paint is mostly gone.also never driven on the public roads before only have 6 months till i get my license but drive on the orchard roads all of the time with standard transmissions thanks. for all of the help.

I believe Fuller is the only one that makes the "Road Ranger" trans. Is the shift pattern: 5 with the button down and 5 with the button up like the pattern below?

R 2 4
1 3 5

Also did you try to shift it without the clutch yet?

Bill

the shift pattern is the same with the buttons just 4&5 are in opposite places like this

R25
134

and yes i tried shifting without the clutch and it is better but still not easy

To the best of my knowledge, all Roadragers have had a clutch brake, at least for the 30+ years I've been working with them. To stop the transmission input shaft from turning so 1st gear can be selected at a stop, the linkage is adjusted so the brake applies when the clutch pedal is pushed all the way down. It's only used at a dead stop. It's a lot easier to ease the shifter into 1st. as the vehicle comes to a stop, rather than fighting with it after it's completely still. Of course, on initial startup, etc., that might not be an option, or when a rig has been idling in neutral for a while.
Jerry

The reversed 4th./5th. shift position is only on the "RTO" series transmissions, with 10th. gear overdrive. It's possible to change from direct drive high gear to overdrive by simply assembling the cluster gear differently. I've converted direct-drive transmissions to OD by swapping 2 gears on assembly.
Jerry

if it has a clutch brake i dont think it works because i have to wait about 5 seconds before it will go into gear

Jerry,

The ones I drove were from the early 70's. It was a little bit of a problem going from idle to first, but when driving it, I always would put it into first before a complete stop and it would go right in.

Are the ones today reasonably drive-able using a clutch if one preferred?

Bill

Jerry is right on the money about the reversed 4th and 5th shift position on the early roadrangers. Eaton made a bunch of the RT910 transmissions from the mid 60's on up to the early 80's that worked on the 250 to 300 horsepower diesels common back then. Final gear was direct 1 to 1 and not an overdrive. Overdrive could be achieved by switching the 4th and 5th gears on the countershaft. RT510 and RT610 transmissions were lighter 10-speed roadrangers suitable for the gas engine trucks with airbrakes. With a little practice they are all easy to shift without the clutch

That is exactly what I drove. It was a '71 GMC 9500 Tandem, 637 V-8 gas, Air Brakes and a 10-Speed RR, which I believe was a RT610. The GVW was at 46,000 though.

Some of the things that can make them hard to shift can be rusty or galled shift rails in the shift cover or the wronglubricant. When this transmission was produced it was designed for straight mineral oil. Using the wrong lubricant can make them hard to shift. I now use 50 wt synthetic on all of my Fuller transmissions. They last forever and shift much easier. Just because the truck is extremely low mileage doesn't mean you can't have bad bearings in the transmission. The smaller fuller 10 speeds were also more difficult to shift because of the higher rpm's of the engine. Todays over the road engines operate between 1200 and 1600 which makes them easier to shift every generation of fullers shifts easier. I learned to drive on fullers in the mid 60's without using the clutch. The old engines were so underpowered and had such a small operating range that a person was constantly shifting and shifting without a clutch was the way the old timers of that day did it. Old habits are hard to break. I still drive one of our trucks occasionally and I only use the clutch to start

so how do i know what transmission i have? also what is the correct way to adjust the clutch?

most of the time there is a decal or plate mounted to the dash or on the backside of the sunvisor on 70's era trucks with the shift pattern and transmission model on it. also check for decals inside glove box. When you adjust the clutch you will want to adjust the clutch brake as well. You never specifically said you were familiar with non synchronized transmissions the clutch and adjustment may be fine it may just be a matter of fine tuning your timing. shift speed-rpm drop-road speed-gear ratio= smooth shift

how do you adjust the clutch brake? also it is military and i cant find any decals anywhere.

By the way, what engine do you have in there?

Bill

401M and when i bought the truck there was a cab and chassis with it that has the 401M and a Allison 4speed auto that i want to use in my 47. I'm not sure it runs yet but i hope it does

I never saw (or heard of) a GMC V-6 with a Road Ranger. Is it factory original?

it doesn't look original because the frame mounts look like plate steel bent with some supports welded in instead of a stamped peace, but the shop manual said it could have had that engine and trans. the guy i bought it from, bought it from an air base in oregon.

This type of clutch is easy to adjust but you either need two people or some way to hold the clutch pedal down to the floor to make the adjustment.

Remove the 4 bolt cover from the bottom of the flywheel housing. Turn the engine over by hand until you find the adjusting window on the pressure plate. Older clutches have a 3/8 bolt (9/16 wrench) that holds a 'tang' about 1.5" long. This tang keeps the adjustment ring from moving on its own. The adjustment ring is make of cast iron and reminds me of a castle. Remove the tang and put a bolt with a nut on it to use as a prying fulcrum to turn the adjuster ring.

With the clutch RELEASED, that is, no one pushing on the pedal, a properly adjusted clutch with a clutch brake will have a gap of 1/2" between the throwout bearing and the clutch brake disc with the brake disc shoved tightly against the transmission input housing. If this gap is too large (usually the case), have your buddy hold the clutch pedal down to the floor while you turn the adjustment ring clockwise as viewed looking forward in the vehicle. The adjustment ring can be stubborn to move, especially if it hasn't been moved in a while--you may have to get things started with a hammer and punch.

After you get the 1/2" gap right, look up on either side of the throwout bearing to see the fingers that pull the throwout bearing away from the clutch. With the clutch completely released, there should be a 1/8" gap between the throwout bearing and the release fingers. If this gap is not correct, make sure the clutch linkage is free and that the pedal is indeed going clear up in the cab. IF these conditions are satisfied, adjust the linkage to provide this gap.

When you are done there should be 1.5" - 2" of free travel at the pedal in the cab. AS the clutch wears this free travel distance will decrease and the clutch will require readjustment. However, it should only require an internal adjustment. If you feel carefully when pressing down on the clutch pedal with the engine off you might be able to feel the clutch brake as increased pedal resistance at the very bottom of the pedal travel.

Newer clutches require the same procedure except that the adjuster ring is turned with a small rack gear in the pressure plate. If memory serves a spring-loaded 9/16 bolt head turns the gear. This is similar to a manual brake slack adjuster. Just remember to get the adjuster ring to turn clockwise you need to turn the gear counter-clockwise.

i don't see the clutch brake, could it be that someone used the clutch off of the original transmission on the roadranger?

The clutch brake is about 5 to 6 inches in diameter it is a floating ring at the back side of the throw out bearing around the transmissions input shaft it will have a tooth on its ID that rides in a slot on the in-put shaft ensure it is still keyed to the shaft.
When the clutch is fully depressed it gets squeezed between the back of the throw out bearing and the front of the transmission to stop the in-put shaft from freewheeling. When the truck is in gear and rolling you should never fully depress the clutch peddle so that this brake is engaged it is meant only to stop the transmission's input shaft from free wheeling. The first time that the clutch brake is engaged with the weight of the truck pushing on it, it will most likely break it buy sheering of the teeth that key it to the shaft.
That said the clutch brake is adjusted with the linkage in the pedal the clutch is not it is adjusted in the manner Racecarl described above. First step is to see if the clutch break is in good shape and adjusted properly it should be tightly held between the front of the transmission and the throw out bearing when the pedal is fully depressed right at the bottom of pedal travel. If this is the case the clutch brake should function fine and don't mess with the pedal linkage any more.
After the clutch bake is in order it is time to adjust the clutch. If the pedal is at the top of travel when the clutch engages and disengages it will need adjustment find the adjuster on the pressure plate through the square inspection hole at the bottom of the bell housing you may need too bump the motor over till it comes to the bottom and is excisable thought the inspection hole. Their are a few different types the easiest to do will have one or two smaller bolts that hold a retainer on that prevents a larger bolt from turning this larger bolt is the adjuster. This adjuster will not turn unless the pedal is fully depressed so have a friend push in the clutch while you turn the adjuster clockwise for more free play counter clockwise for less give it two or three turns let the clutch up and check the free play at the peddle continue this process till you have your two inches of free play and the clutch is fully disengaged well before the clutch brake engages replace the adjuster retainer and inspection cover and you should have a properly adjusted clutch and clutch brake.
Remember the linkage should only be messed with if the clutch brake is out of adjustment it is not used for adjusting the clutch but the brake adjustment must be done fist if needed if the brake is in adjustment leave the linkage alone the clutch is adjusted with the adjuster on the pressure plate not the linkage.

so if it has a clutch brake the throw out bearing would move towards the transmission instead of away from it? mine moves towards the engine.

There should be a data plate somewhere on the transmission that shows the manufacturer and the series number. It might be buried under decades' worth of grime, or even be missing altogether.

Most of the Roadranger transmissions use a double-disc Spicer clutch that pulls, not pushes with the throwout bearing to disengage. The clutch discs fit inside a deep counterbore in the flywheel, and there's a "floater" plate between the two discs that splines into the recess in the flywheel. There is a threaded ring built into the pressure plate that is adjusted in or out by turning it with a specially-shaped pry bar to achieve just enough clearance for the discs to disengage when the clutch is depressed.

Adjust the pedal linkage first, to apply the small, single-disc brake at the back of the throwout bearing when the pedal is pushed all the way to the floor, then adjust the clutch disc engagement with the adjusting ring. There is usually a sighting window built into the bellhousing to eyeball the throwout bearing, and to use the adjusting pry bar. When everything is working properly, lock down some anti-rotate brackets on both adjusters to prevent the settings from slipping. Unless the clutch really gets abused, it's unlikely you'll need any more adjustment for a long time.
Jerry

Edit:
Hevi Hauler, I posted my reply before I saw yours! You did a better job of explaining the procedure!
Jerry

the plate has two numbers i cant read any of the paint but the first one is 3820155 the second is 18827-F-1.

I have only seen one Roadranger with a push-type throwout bearing and that was in a Ford 8000 truck with a 3208 Cat engine. This truck had a air push button on the gear shift lever that sent air to a piston that pushed against the input shaft and stopped the transmission gears from turning. It was kind of a wierd set-up but it worked.

so could someone have used the throwout bearing setup from the original transmission.

Wow, I am gone 3 days and there are 33 post on this thread. I'll have time to reply more completely once I get back from the Kansas show.
Sounds like most all of you know a little bit about these clutches and transmissions, I'll try to pull all the good bits together and make sense of it next week.

Later,
Grigg

Not all Fullers are the Road Ranger. The road ranger is split in 2 sections. You go through the first 5 gears (or more if it is a 12 or more speed trans), then shift to the high side & shift through the next 5. You don,t split shift like a 2 speed rear end. The brake on the clutch acts like the syncros. It stops the shaft so it doesn't clash.

The brake is only used too stop the input shaft from free wheeling when the truck has been idling in neutral with the clutch engaged. They are used on most heavy truck transmissions with heavy internals that act like a flywheel and don't like to stop spinning after being set in motion.
I always hate getting in a truck after an inexperienced driver has blown the clutch brake out of it.

Pull type clutches with clutch brakes are quite old, very old actually, my 1925 Mack AC had one.

A normal automotive clutch is push type, the throwout bearing is pushed forward against the fingers of the pressure plate to disengage it.
this is a picture of the throwout bearing (but not totally correct, as it has the wrong input shaft bearing retainer and input shaft.)
[IMG]http://thumb9.webshots.net/t/69/469/4/22/46/2270422460080251109ThOpat_th.jpg[/IMG]
In a big truck with this type of clutch and a transmission with a lot of rotating mass they will often have a "counter shaft brake" essentially it is an air cylinder that is forced into a PTO gear to slow it down by friction, the momentary pushbutton to operate it is mounted on the shifter and has air lines on it. I installed one of these on a truck I had, worked great at stop lights. When warm the transmission could take 10 or 15 seconds to stop without it, long enough that people would blow their horns at you, stopped in seconds with the brake.


Many big trucks, and almost all semi trucks have pull type clutches. The throwout bearing is actually assembled as part of the pressure plate, and the "fork" pulls the throwout bearing back toward the transmission to disengage it.
If it is equipped with a clutch brake the clutch brake disc that is keyed to the input shaft will be squished between the stationary input shaft bearing retainer and the throwout bearing, thus stopping the input shaft, clutch, and counter shafts from turning.
Here is a picture of a pull type clutch and the throwout bearing.
[IMG]http://thumb9.webshots.net/t/69/469/4/18/90/2838418900080251109kpCRzW_th.jpg[/IMG]
A clutch brake "(or counter shaft brake for that matter) is not to be used while driving, only when putting it into gear when you are stopped. So for a clutch brake you never fully depress the clutch when shifting through the gears, as fully depressing it engages the clutch brake.

Grigg

It is adjusted when you adjust the clutch, usually by turning an adjustment on the clutch its self.
This manual may help: http://www.roadranger.com/ecm/idcplg?IdcService=GET_FILE&dID=165924

I don't know all the details, as my pull type clutch is self adjusting, and I have not messed with a manual adjust one.

Grigg

No, not all fuller transmissions are Roadrangers.
A Roadranger transmission, which is made by Eaton/Fuller, is a twin counter shaft transmission with a 5 speed box and at least a two speed box all made together. The 5 speeds are shifted with the stick, and any range or splitter shifts are by air cylinders.

Fuller also makes single counter shaft transmissions (up to 6 speeds I think) all controlled by the shifter. These would not be called "Roadrangers".

Those numbers don't tell me much. The model number is the important one, it should have something like RT-#### or RTO-#### or RTOF-#### (the #'s are for numbers like 9510, 6610, or similar.)

Grigg