Disgusted with Cat 7155

[OPCOM]

Cat haters! Complaining about hissing under the floor!

 

[reb87]

give me a call 402-527-5212 and Ill tell you how i run mine... too much typing for me...Ive hauled about 100000 bushels grain in the last two months with mine...

 

[Floridianson]

James thanks for your comments, I was hoping you would chime in. This is where I am confused. Coming off of speed, I have been downshifting all the way to 1st, keeping the engine speed over 1400 like the manual says to. Right before the stop sign, I pop it into N. Are you saying to stop from high speed, you use leave the trans in 16th, let the engine idle down, and apply the brakes all the way to a dead stop? That sure would be easier than what I am trying to do. I just thought it was a big no-no to leave the trans in gear under 1400 rpm. The manual is not specific about any of this.

Right don't down shift and just let the truck coast to the stop then lift handle and place in you starting gear. I can start on a flat no load in 5 or 6th. Just when starting if the speed does not pickup in 3 seconds you chose to high of a gear smack it down one and try to get it going again. Around town I am in 15 th most of the time cause of the slower speed and traffic. Inless I am going for the 67mph I dont use 16th. With a heavy load then shift one at a time and work your way up if not skip two at a time and wind it out. 21 or 24 if you can go there and just a slight let up on the fuel peddle not all the way off.

 

[Floridianson]

From the cat service manual. The clutch starts to engage at approximately 775 rpm and is fully ingaged at approximately 1100rpm. The slection of a correct gear ratio must be made to pervent a long period of time in the 775 to 1100rpm range. If the truck does not accelerate ( pick up ground speed) above 1200 engine rpm in three seconds or less , go to a lower gear.

So it is on starting not coasting we can mess up by takeing to high of a gear.
Keep at it and find the gear that your truck will start correctly at and that will be the gear that after you stop you lift handle and drop in in there and be ready to wow the crowd with one bad @ss truck.

 

[Floridianson]

give me a call 402-527-5212 and Ill tell you how i run mine... too much typing for me...Ive hauled about 100000 bushels grain in the last two months with mine...

To be honest you can't tell someone how to drive a big rig you must learn your truck and then you will be one with the machine.

 

[reb87]

Ive run mine enough there are some little tips when upshifting and downshifting that really help the trans shift smoothly. When downshifting you can just hold the throttle at an even point(not accelerating or decelerating) and shift down. It makes for a smooth jump free downshift. If you are loaded you need to do some downshifting to make good use of the jake brake. I bring the rpm down to 15 or 17 hundred rpm and then hold the throttle even, downshift and hit the jake right after the shift. Repeat till close to the stop and then just cost in, stop and lift the shifter and bypass down to neutral. You dont need to look at the shifter just keep pressure to the left and when you hit the little step left, make sure you pull up so you are solidly in the step and drop the shifter into neutral. I will usually coast in the last few feet in neutral but you dont want to hit neutral while at high speed or for very long. My fuel shutoff solenoid burned up on me at full speed and I coasted to the edge of the road. I thought I should go to neutral and did. The trans started making a little noise after freewheeling for a little ways. I think I should have left it in gear until I stopped....

 

[jrm917]

Hi I am new to this site thanks for all the information guys. I have a m917 dump truck and I want to junk the 7155 transmission and put in an eaton fuller 18 spd can someone tell me where I can get all the parts that will fit, to make this work and how many modifications I will have to do thanks.

 

[NDT]

Holy thread resurrection Batman! Have I owned my 916 for 6 years now? Actually I have come to like the 7155, as opposed to my thread title. JRM917, to swap it out will require a donor truck in a wrecking yard that is equipped with the 855 CID Cummins, and the transmission you want. Grab the flywheel, and verify the SAE number of the bellhousing is correct. You will have to fabricate a clutch linkage and jackshaft.

 

[Karl kostman]

I spent last Spring working on my 920 and when it came time to drive it even after reading all about HOW to shift the 7155 and getting suggestions from folks here that did also help BUT with that said it takes time behind the STICK in this case. I probably put around 500 miles on my 920 this summer and you really cannot hurry this transmission along any faster than it wants to go, at least that seems to be my experience! My shifting improved over the summer by about 300% but again with that said it still requires a certain level of driver concentration on a few things to get it to want to play nice! Its INTERESTING!!!!
Give it and yourself some time it will come around!
Karl