Transmission question?

[Truckie]

I got a transmission question for ya all. I feel kinda dum asking this question but you know what the say the only dumb question is the one you don't ask. So here it goes.
When shifting or splitting the upper gears I don't use a clutch so all I really have to do is pre selecting the upper gear I want to split and when I shift I let off the throttle and let the Jake crack and it splits the gear really nice. This is what I have been doing and no problems, and down shifting pre select and hit the throttle. The only problem I have once in a while is when shifting from like 6 high over drive down to 7, once in a while I get some gear grind and have to rise the rpm for a smooth shift. Am I doing this right? And not using a clutch I am guessing this is also right? I have not had it hang up in any of the gears and it is shifting really smooth, I just want to make sure IM doing this right.
This is the first 13 speed I have driven that has acutely shifted nice without hanging up in gears or any other problems.
I got 10 years of driving under my belt and believe it or not 99% of my driving has been shifting 8 speeds 8 double LL 9, 10, and 15 speeds.
Man do I miss not having the deep reduction. But IM slowly getting use to it.

 

[Pacific]

Is your truck Mack powered or another brand ie Cat Cummins ?

Most Macks pull pretty low or atleast the older ones did the last one I drove had a 8spd Mack transmission.

The trucks I drive all have 13spds and they are all slightly different shifting. Burp shifting with the JAKE is ******* the transmission you really shouldn't do it another thing is you get used to shifting with the Jake then you have troubles shifting without it.

You try burp shifting a older 9000 Ford you end up with a Jake stall thats scary I had it happen lucky it was on a dirt road. The newer trucks have oil pressure switches to prevent it from happening.

When splitting you should dip the clutch you have to remember the splitter isn't really designed for floating. Its alright to float the rest of the transmission most of the time its smoother to float than use the clutch.

Check your air tanks do you drain them every night ?

If you don't drain your air tanks drain them see if you get lots of snot out of them if so its into your air lines which means its in your splitter lines. When the snot gets into the transmissions air lines the transmission starts getting lazy and slow shifting.

How much weight are you pulling ?

How much power do you have under the hood 470 ?

Most of the time you can use full gears and use the splitter when your really heavy or does the truck have tall gears in the diffs.

As for deep reduction most of the time we don't need it here and we are pulling out of steep driveways etc. Usually Low gear is good enough the only thing you need deep reduction for is trucks with low power.

Guys with 15spd rarely use the 5 deep reduction gears the truck is shifted like a basic 10spd.

The 8LL is a nice transmission for vocational uses but for trying to get the rpms down on the highway a splitter would be good.

Anyhow try get used to shifting without the Jake and try use the clutch splitting shifts all you need to-do is quickly break the torque.

I think I would have more problems shifting a 10spd because I'am so used to the 4 on the bottom 4 on the top and flipping the splitter.

 

[Truckie]

The tranny is an Eaton Fuller, and the engine is a Mack 460 HP. 90% of the time I am at 80,000lbs or more with the permit loads which are around 90,000lbs.
Running empty I don't always split the gears, but when loaded I do. Low gear in this truck is pretty low and works well, but with my other truck with the 8LL deep reduction was a must when loaded, it was a Mack also with there 460 engine.
I Drain my air tanks everytime I fuel up which is every 3 days.

 

[maniac]

I NEVER use the clutch in my 18 speed, BUT you shouldn't pre- select either, when your ready to shift just move the button and release the gas pedal.

Pre-selecting puts unessesary stress on the fork in the back half of the trans.

How do I know, I replaced the back half ONCE, that was all it took for me to learn not to do it.

 

[Pacific]

Well that rules out the snot in the air lines that is usually the culprit for a lazy splitter. Have you checked the oil level in the transmission lately or changed the 80/90 ?

It sounds like your Mack might be geared on the tall side I know guys grossing 90,000lbs with trucks with M-11 Power. As our legal gross weight here is 140,000lbs a 80,000lb gross is considered a light load most trucks are licensed for 116,000lb gross. The guys that pull super Bs are licensed for max 139,900lbs.

If you keep having problems with your transmission you may have to have a shop look at it you don't want to second guess problems or it may turn into something expensive.

When you drain your tanks you should open the petcocks and let them drain over night then if there is snot in the tanks it has a chance to drain out. The sign of alot of oil snot means your compressor is passing oil and its about to give up the ghost. A slobbering compressor also plugs up your air dryer if you have one.

I had to change the compressor on a International gravel truck with detroit power it was a sob to change because everything had to be done through the dog house in the cab. Its a sob when your laying on your side all cramped up working with one hand trying to get the bolts out then lift the compessor out with one hand

 

[Truckie]

Pacific IM not having trouble shifting or it hanging up I just wanted to make sure what I was doing was right. Some of the other 13 speeds I have driven have had a problem like you are describing. The oil snot in the tanks and what not. When I drain the tanks I let them blow all the way down till they blow clean. This truck so far has had no problem with wet tanks, snot or a bad air dryer. It just had a new cartridge put on the day I picked it up. This one is just fine, with the exception of when I screw up. ;p As far as pre selecting I do like you have stated maniac, just flip the splitter and off the go pedal. I just call it pre selecting, I don't acutely ride around with it flipped, flip it and switch it all at once.

 

[Ak HDM]

Fuller says not to preselect the splitter, just the range , as the range cylinder won't shift untill the shift lever is moved to the neutral position, where the splitter cylinder is trying to shift when the button is moved.
On the back of the trans there is a filter/regulator that cuts the pressure down to about 60psi for the trans air system. You might want to check the pressure coming out . The filter may be getting a little dirty. If the grinding gets worse or more often, I'd get it checked out as the splitter synchro may be going away. By the way the filter/regulator is up high on the rear and will have the line from the truck air supply going to it.
Hope this helps.
Mike

 

[Pacific]

Like I meantioned it doesn't hurt to dip the clutch if shes grinding and flip the JAKE off because its pulling the engine down too quick.

As they say if you can find it grind it

 

[maniac]

I just call it pre selecting

OK, I misunderstood.

 

[Brickman]

I've heard that 13s can die with no notice. Suddenly you have no gears.

I almost always Jake shift, flip the little red button, one "blap" from the Jake and its back to Kitty powering down the road.




Some thing I learned when belly dumping was to stab the clutch on the first few shifts until you get the speed up. Like the first half of a double shift. You have to be quick to let off the throttle otherwise the engine revs too much and you have a really hard time to grab the next gear.
Worked really well when pulling max loads on the soft ground of construction sites. If you've ever belly dumped on site like that the loader ops would not quit loading until dirt was spilling off all sides.