Engine, Tranny, Driver? All 3?

[shewolf]

Questions about this "new to us" truck we're in. '99 Int, 9400, M11 Cummins Engine 370 hp, Eaton Super 10 top 2.

Hubby has never driven the Super 10 before and this is the first truck with manual trans I've driven. SOOO, neither of us know much about this thing.

First question Hubby has is, "Is it normal with trans in neutral and you move the stick back and forth for it to sound like you are switching the splitter back and forth?" No other truck/trans he has driven did that so he's wondering :wtf: ?

Next question/problem, With trans in 10th if you push in the clutch to attempt a downshift, or any other reason, truck starts bucking and jumping, will do that for several seconds until it apparently decides to stop, nothing you do will help.

We thought it was driver error/maybe we should let it auto downshift to 9th and it does appear that once it auto shifts to 9th you can push in the clutch safely (most of the time). However once on a pull today the trans had auto downshifted to 9th, we were at approx 50-55 mph and it began to jump in the same manner. :wtf:

Talked to truck owner, first thing he asked was "Does it do it when you push in the clutch in 10th?" Yes, it does. He says it has been doing that ever since he had the new engine put in in July. New engine has approx 40,000 mi on it.

Anybody ever had this problem? Sounds to me like could be anything from some kind of transmission valve? fuel related? ecm or other sensor like throttle sensor?

I know if it was my truck and I had just paid $18000 plus for a new engine I would be back at Cummins asking some questions. :D

[Foxfire]

The air sounds are normal. The bucking is not. I never used the clutch with a super 10 unless I over reved it and got it "stuck" in a gear....lol. When you are in 10th and it starts to lug down, let the RPM's go down and then simply let up on the fuel for a minute and then back on the pedal. It should make the drop all by itself. Driving a Super 10 is all about listening to the RPMs and preselecting the upper or lower gear on that one button on the side.
Super 10 is made to automatically down shift from 10th to 9th. And from 9th to 10th. This is the new Super 10's I am talking about. The old ones weren't like that. I may be wrong but maybe you aren't giving it enuff fuel to keep it from bucking like that. Just a thought.

[shewolf]

Thanks for the input Foxfire. At least we know from someone who has driven one that the air sounds are normal. :D

As for the bucking, we have tried everything when it starts, to more fuel, less fuel, pushing in the clutch, letting out the clutch, it still does it after you get the shifter into neutral until you brake enough for rpms to fall way down, then it stops and you can get it into another gear and try again.

Here are 2 examples of when it happened tonight.

First one I was driving, going up thru the gears from a stop. I was going up a hill and apparently messed up and preselected "low" before going into 9/10 position. I quickly realized what I had did and put selector button into high, let off throttle and it shifted into 10th normally. All was well for a couple miles until the first time I had to get on the brakes and start slowing for a stop. As soon as it downshifted into 9th it began to buck like crazy.

The truck owner told us this is one of the scenarios that will make this happen in his experience. He doesnt know why either. Apparently it confuses the transmission if you mess up and dont leave selector in high 8th, then shift the stick into 9/10th with selector in high. :wtf:

The other scenario he says it happens is when you push in the clutch for any reason while still in 10th gear.

The second time it happened tonight Hubby was driving. He says he shifted correctly from 8th, leaving the selector in HI and going into the "big hole" to let 9th and 10th autoshift. He got on the brakes to slow for a turn, the trans auto downshifted to 9th and immediately began bucking.

We are puzzled by it for sure. Hubby says he has forgot several times and put the selector back into low b4 going to 9th/10th and that is probably the culprit for several times its happened to him and Im sure that is what I did both times it has happened to me. Something about that makes it go crazy the next time it downshifts to 9th. :wtf: ?

He also probably pushes in the clutch when stopping earlier than I do, I got used to driving the auto shift and letting it downshift thru all the gears for me when coming to a stop, so I waited until the last moment before pushing in the clutch and probably wait longer with this manual too. I know I at least wait for it to downshift to 9th and even longer until Im forced to try and downshift further or brake to a complete stop. BUT shouldnt you be able to push in the clutch in 10th or are u at the mercy of that auto top two?

Any help is appreciated. Chatting the other night I gained some good advice thanks to Foxfire! I learned to preselect with the button instead of waiting until neutral to try it. I'm also floating the gears and having more success than with the clutch. The only time I'm using the clutch is just like u said FF, when I've overrevved it and then I just tap the clutch to get it out of gear. Also figured out tonight I was trying to shift too high RPM so I just started shifting ASAP and had a lot better success. Doing pretty good with that method on flat ground, got my first taste tonight of stop lights, and starting out on steep hills, need some more practice for sure but Im undaunted, it was fun. :D

[HSLD]

I removed the auto on the top two in my truck. Maybe it was my driving style, but I couldn't master it. Example, I'm in 9th, go to pedal it a little up a slight grade, and it pops up in 10th, and bucks a little. Same thing when you go to slow down (like you mentioned for a curve), you're in 10th, where you want to be, back pedal it slightly, and she drops down to 9th. I hated it. So, I removed it.

He's the key to shifting a Super 10. If you do use the clutch for shifts, barely depress it. Say 1/2" to no more than 1" on a properly adjusted clutch. Try to shift without the clutch or any clutch pressure. Like any other trans, it'll let you go through the gears at the right RPM without the clutch.

Begin the shift at 1500 RPM and complete it by the RPM drop at 1100 RPM to 1200 RPM depending on the truck. Some trucks like the shift completed at a little higher RPM and like the shift begun at a little higher RPM. But, 1500 & 1100 works on a lot of trucks. It's a good starting point until you get used to the trans.

Beyond 6th gear going up or down, think 25 MPH for 7th, 35 MPH for 8th, 45 MPH for 9th. That's a good rule of thumb for most trucks with a Super.

The lazy way to go back down through the gears (without auto shift)(did I mention I hate it?), go from 10th to 9th, let the speed drop to 25 MPH, shift to 7th, let the speed drop to 15 MPH, shift to 5th. Or, from 10th, let the speed drop to 35 MPH, shift to 8th, let the speed drop to 20 MPH, shift to 6th. you know the rest...........

v/r

HSLD

[Foxfire]

The lazy way to go back down through the gears (without auto shift)(did I mention I hate it?), go from 10th to 9th, let the speed drop to 25 MPH, shift to 7th, let the speed drop to 15 MPH, shift to 5th. Or, from 10th, let the speed drop to 35 MPH, shift to 8th, let the speed drop to 20 MPH, shift to 6th. you know the rest...........

v/r

HSLD

This is what I was talking about when I said shifting from box to box on the downshift. You are most welcome she. Anytime I can help someone figure out something I am familiar with I am glad to help. You might want to talk to your boss about doing like HSLD and take that autoshift out of 9-10. Personally I hate it too.

[Capt._Chaos]

I drove a Super 10, and it wasn't a bad transmission once I was used to it. The Top 2 Feature needs to be disabled though.

If you're having trouble with it bucking, kep in mind the Intenational will drive differently than your old Freightliner.

For now, I would suggest making sure the fore-aft isolator in the driver's seat is locked (seat won't move) and see if that helps you get used to the truck a little easier.

Gently rolling into the throttle during acceleration will help smooth things out too.

[shewolf]

What is involved in disabling the top 2? We will suggest that to the owner and see if he is agreeable. After first of the year we may become the owners but NOT until I know whats up with the truck.

Are you saying it is impossible to shift the Super 10 without disabling the top 2 or do we have a mechanical issue with our Super 10? The owner apparently experienced the same thing when driving this one too.

As for the bucking, I know which bucking you are talking about Capt. Chaos, the one where you get on the throttle a bit much, that throttle is VERY sensitive. We understand the wheres and whys of that one. the throttle on this truck is almost TOO sensitive, have to baby it when starting out and sometimes it just bucks anyway. Then when you start hitting bumps in the road in that straight truck your foot starts bouncing on the throttle but thats not the same things thats giving us a problem.

Its the one that happens when you are totally OFF the throttle and push in the clutch that we cant figure out. Or you can simply be stepping on the brake and and be off the throttle to slow down which makes the trans downshift to 9th and the instant it drops to 9th it begins to buck. When this happens it sounds and feels like the engine is revving up and down by itself, feels almost like the accelerator on a car when it "sticks" if you've ever had that happen. And for a few seconds you have no control of that beast, its like its stuck in gear and depressing clutch doesnt appear to do anything. Kind of similar now that I think about it to when Hubby had a clutch with broken springs on it and it would hang him in gear, almost couldnt stop.

Thanks again everyone for the help. Keep it coming if you can come up with anything else. The owner said if it keeps it up we will go to the shop, sounds like that may be the plan.

[HSLD]

No, it's not impossible to shift with the auto feature, it's just hard to get used to. I think (especially my truck) that the throttle was a little to sensitive which caused the auto on the top two to shift up and down when I didn't want it to (like slowing slightly for a curve or pedaling it a little for a slight grade). I found this to be a real problem on some on and off ramps. You're in 9th, you want to wind it a little tighter in 9th before shifting, and bam, the auto pops it up into 10th.

I'm not sure what exactly it takes to get it off, but it took the dealer a few minutes to disable it. Maybe it's a change to the ECM? I fought with the auto feature two days after buying the truck, then took it back and had it removed.

v/r

HSLD

[nitestar]

I was at my Freightliner shop the last time I was home and a driver was there with a shifting problem,. It was a Super 10 and they found it to be the computer for the tranny and it needed to be upgraded some how. I think it was called something else but that is the jist of it.