why cant i downshift my 18 speed without grinding

Put a piece of duct tape over your tach, you don't need it.

What you need to do is learn how to shift by the MPH gauge. Learn what gear you are in at what MPH by heart, then you will know what gear you need to be in at what road speed.

That is why you are screwing up your shifting, new truck, new trans, you have to learn the new shift points.

 

I stuck a gps unit over my tach. Then I realized that it had a speed readout on it so I stuck another one over the speedometer. I still forget where I'm going half the time, though.

 

my truck has a 400 big cam cummings in it now it came stock with a 425 cat i know now that the clutch brake is bad or has came apart or somthing i have an appontment to get it fix at our local kw dealer but i think there is another problem i have been shifting without the clutch after i figured at what i was doing wrong i found out that when i take my driving test that i have to use the clutch during the test or they will fail me for improper clutch use so i took the truck out a little while ago and tried to double clutch like i would have to do in my driving test and once again there i was again grinding and scraping could there posablely be somthing wrong with the truck because shouldnt useing the clutch be about the same as not useing the clutch? i would not think that the clutch brake would have anything to do with the shifting i know the truck had a clutch put in it about three months before i bought it if it was not adjusted right would that have something to do with it? the person that was rideing with me was also having the same problem before he thought it was just the cummings makeing it tempermental but he is starting to think something is also wrong with it he has been driving for a while and he can not shift with the clutch ether is it the motor or could there be somthing wrong inside the tranny or is the clutch just out of adjustment?

 

Are you pushing the clutch pedal all the way to the floor when you are double clutching?

 

no i am not pushing the clutch to the floor just far enough to release presure, about half way or so maybe not that far the clutch catches close to the top that is why i think it may be out of adjustment but the truck was suposseably a working truck up until about two weeks before i bought it and it has not sliped on me any but i also havent been loaded yet

 

That's strange. They only took a point off for floating the clutch. I asked the tester about it beforehand to make sure I wouldn't get a point every time I floated it instead of double clutching. She said it was just one point for the whole test so I took it.

 

thanks ill ask the tester about that im just going on what the new cdl manual that my girlfriend got the other day and what the dmv said. she is also getting hers after i get mine that way we want have to find someone to ride with her to that has been the biggest problem that i have had is tring to get someone to ride with me im to close to just take the truck out and wind up getting caught by the law driving on a leaners alone she is going i guess tomarrow to take her learners test that is why im tring so hard to get mine now so i can help her out

 

Clutches are for take offs only.........

 

If I had to retake my CDL driving test today I would most likely fail it for not double-clutching. Neither that after grinding the gears double clutching so bad the instructor wouldn't think I actually had been driving for over 17 years.

 

is it harder to shift a truck with a cummings in it than a cat or detroit?