i have a 04 LLY durmamax allison with 11,500 miles and today going down the interstate it felt like it downshifted and started banging rev-limiter. i slow down and it stops. i go to the off-ramp and it does it again this time going 40. i slow down more and now it won't go above 25 and 2k rpms. anything i can look at? it does this in every gear.

You done any mods or flogging to the truck?

You done any mods or flogging to the truck? no 100% stock. i did dyno it i guess?

No Service Engine Soon light on The drivers information center? If your in Tow Haul and you lift and slow it wouldn't be uncommon if heading down hill for a grade brake to occur as your describing.


What I don't understand it was you describe some what as limp Mode with not going over 25 MPH at 2000 rpm's.





Being that new and with a SES light illuminated it would be best to bring it in for service as oppose to messing with anything.


Good luck and please let us know how you make out.


Mac





On edit a Dyno run is nothing.Edited by: Mackin

No Service Engine Soon light on The drivers information center? If your in Tow Haul and you lift and slow it wouldn't be uncommon if heading down hill for a grade brake to occur as your describing.


What I don't understand it was you describe some what as limp Mode with not going over 25 MPH at 2000 rpm's.





Being that new and with a SES light illuminated it would be best to bring it in for service as oppose to messing with anything.


Good luck and please let us know how you make out.


Mac





On edit a Dyno run is nothing. no, no lights. and no tow/haul just going 65 down the interstate making a lane change. http://www.dieselplace.com/forum/smileys/smiley19.gif

Then I would just drive it ,if it's normal,now. Perhaps a growing pain that will either disappear or rear it's ugly head for diagnostics.





You could call your service department and see if they would like to scan it or take it for a spin and scan . They might just say cannot repeat ,can't help ,although.


Good luck


Mac

Then I would just drive it ,if it's normal,now. Perhaps a growing pain that will either disappear or rear it's ugly head for diagnostics.





You could call your service department and see if they would like to scan it or take it for a spin and scan . They might just say cannot repeat ,can't help ,although.


Good luck


Mac no it isn't normal now. it still does it. i plan on taking it in tommarow, just wondered if anyone had any insite? im going ot have to get it towed there becouse it makes some crazy noises now.

What kind of load were you pulling? Did it feel better after ignition recylce ( the next time you ran the truck after shut off)? This problem now will not go way.

mike

What kind of load were you pulling? Did it feel better after ignition recylce ( the next time you ran the truck after shut off)? This problem now will not go way.

mike nothing at all. only thing the truck has pulled is a reg. cab short box truck 400 miles and a few things around town. it does the same thing again and again. no matter how many times i shut it off.

What kind of load were you pulling? Did it feel better after ignition recylce ( the next time you ran the truck after shut off)? This problem now will not go way.

mike ok i could reproduce it 3 times now its acting like nothings wrong. although its whining really bad? this is confusing lol

if the RPM's wont go up, that problem is on the engine side, not the trans.


Likely a code could be set and not trigger a light "type B DTC"


Get it in to the dealer and see what they can find.

well i took it in today and it started doing it again on the way to the dealer. they suggested fuel filter? doesn't seem like a filter problem to me though, well see. i also rembered that 2 tanks ago i put about 10 gallons of off-road diesel in. would that do anything?

Sure it might a bad load of fuel can easily mess with performance.Eric I'm sure has this pinned down and is right on the money.


I'd stay away from off road fuel. If it's dyed and the dealer gets wind of it you may have to part for the repairs in the future.





Mac

http://www.dieselplace.com/forum/smileys/smiley5.gif Greetings, I'm new to this forum. I was on vacation for several months and had consideral problems like yours, truck would lose rpm, couldn't get over 20 mph, and pulling a 33.5 fifthwheel. Changed the fuel filter, that did help but it was mostly bad injectors. I don't know if it is the same problem as yours but that may a source to recon with.


Good luck