I have some mechanic questions?

[sbatson]

I'm driving a 05 century with a 500 detroit and say youre going up a hill or on flat ground and when it coast ( governed at 73) it makes a grinding noise untill you can get on the gas again and it sounds like it is coming from the trany and it only does it when I'm hooked to a trailer loaded or not, any ideas? Also with a trailer loaded or not and I hit a bump, big or small it sounds like it bottoms out in the rear, could it be bags or shocks back there?

[TGTLLC]

i would have the carrier bearing/center support bearing checked out.

my classic did that and it was the bearing on the drive shaft.

could also be the bags aren't inflated enough causing a wired drive shaft angle.

[sbatson]

That might be right because like I said it bottoms out in the back like something is bad so bags being weak probably could cause something else down the line, makes sense to me.

[TomB985]

Sounds like your suspension ride height is too low...I remember the mechanics telling me that if they set it too low, it will change the driveline angle too much, and it will cause all kinds of problems in the driveline...as well as bottom out...

[Windwalker]

Sounds like your suspension ride height is too low...I remember the mechanics telling me that if they set it too low, it will change the driveline angle too much, and it will cause all kinds of problems in the driveline...as well as bottom out...

Use a tape-rule, and measure the height of the frame on other tractors and then measure yours. If you have a problem with the height, you'll notice the difference in height.

[Kranky]

Best way to check ride height is to obtain the manufacturers specifications for the type of air ride on that particular truck.

The service manual will outline the proper dimensions and exactly where it is to be measured.

That might be right because like I said it bottoms out in the back like something is bad so bags being weak probably could cause something else down the line, makes sense to me.

Improper ride height is not caused by "the bags being weak", it is caused by the ride height control valve or linkage rod being out of adjustment, defective, or broken.

Air ride when working properly will maintain a constant ride height whether the truck is empty or fully loaded, unless the truck is so grossly overloaded that full reservoir pressure (120 lbs.) applied to the bags cannot support the weight.

[TGTLLC]

for freightliner classic`s and fld`s lift is supposed to be 3 and 1/2 inches if i remember correctly. not 100% positive for other makes but might be a starting point to look at if your manual doeset tell you,

[Doghouse]

Best way to check ride height is to obtain the manufacturers specifications for the type of air ride on that particular truck.

The service manual will outline the proper dimensions and exactly where it is to be measured.

That might be right because like I said it bottoms out in the back like something is bad so bags being weak probably could cause something else down the line, makes sense to me.

Improper ride height is not caused by "the bags being weak", it is caused by the ride height control valve or linkage rod being out of adjustment, defective, or broken.


Absolutley right on the money Split.
The guys put in 2 trannies before I,...repeat I figured out they had the ride height set wrong.

Air ride when working properly will maintain a constant ride height whether the truck is empty or fully loaded, unless the truck is so grossly overloaded that full reservoir pressure (120 lbs.) applied to the bags cannot support the weight.

[sbatson]

Well I talked to the office today and they said they checked the bags and they are good, but said I had the tandems all the way back on the trailer, well ya I did so my load would weigh out but it does it no matter heavy or not, so I told them about the ride height and carrier bearing so we will see what happens.

[Doghouse]

So what if you had the trailer tandems all the way back. If you were legan on the tractor,...why would this make any diff?
Are they pullin' your leg?

[sbatson]

Thats what I said , I told my manager I had to put in the back to get the load to weigh and I know it will ride like crap that way but that dont explain the bottoming out in the back and the grinding noise under the trany.

[sbatson]

Well I forgot to report on here what my problem was, it was the self leveler for the rear susp., replaced it, amazing it was like new no problems since then.

[heavyhaulerss]

Well I forgot to report on here what my problem was, it was the self leveler for the rear susp., replaced it, amazing it was like new no problems since then.

thats the same as air bag prob. lol. i adjusted mine the other day & adjusted the rear bags too low & it made a grinding noise. pulled over & adjusted the adjusting rod to rais bags & noise went away. your bag must have been bottoming out. the leveling sys prob let the air out but would not activate to put air in. anyway. glad you got it fixed & glad you posted what the prob was.