I have noticed on two occasions recently right after I have started my truck and put it in reverse it didn't move for a second or two.

I recently took a trip from south Louisiana to northern Alabama pulling a 24' trailer. No problems going up but on the return trip I estimate I was pulling a gross weight of between 15-18,000 pounds. In the hills It felt like the trans was slipping and at times it sounded like a jet engine was under the truck and then all of a sudden everything would quiet and the rpm's would drop to about 2000. The trans temp never got above 190 and the engine rpm's never really went above 2800. Other times the trans would shift normal with no loud sounds. At first I thought it was the fan clutch but the engine temp never varied much.

Was wondering if the trans is slipping and if it is what would fix it or just upgrade it ??? Any help is appreciated.

Thanks in advance for the help it is appreciated. Jeff

PS truck is stock and I really havn't done much towing with it.

Jeff
Need more info. year, mileage, mods, how often Ally was serviced.
mike

04 with 35,000 miles, completely stock,spin on for allison changed every oil change, all at about 5000 mile intervals. I might also note that I have noticed my fuel mileage has dropped off some, about 1-1.5 miles per gallon, I hand calculate every tank.

hi,could be you are hearing engine fan engauging and your trans slipping

Jeff La
I think you are hearing your fan clutch and very possibly are experiencing Torque converter slippage under load. Tech 2 would show you if converter was slipping. You can call me if you like.
mike

I just have had the same problem...It even was happening when not towing. Not as much, but alittle. Does anyone know if this excessive noise is normal.. It would sound like the fan cluctch would ingage and sound like a jet engine like you said and then go back to normal after a few minutes. The rpm,s did not increase. It would happen mostly on an incline. Also, going down a steep hill it would down shift with the brake to slow the vehicle down and when I would hit the excellerator to continue it would shift excessively hard out of the down shift. Whats going on here.

alsup by no means am I a tranny guy but it sounds like you might have your tow/haul button on the tranny has a built in thing that will help you slow the truck by downshifting when you are slowing Hopefully MikeL will chime back in

Thanks, Yes, I had the tow/haul on and I realize it helps shift down to help in slowing, but when you hit the accellarator to continue it should not shift eccessively hard out of the down shift back to normal with a cluck....Thanks and I would accept all info from everyone who has any......................

I would believe it to be my torque converter slipping. At first I thought it was my fan clutch but I watched my temperature closely and having experienced this before I saw the temp fluctuate when the fan does come on but this time the engine temp stayed steady with no fluctuation. If I remember correctly the engine temp was only around 210 degrees, but I'm not sure (CRS).


If it is torque converter slippage how long will it do this before the torque bites the dust ??

Thanks I really Appreciate the information. Jeff

210 degrees is normal activation of your fan clutch I do believe. At least mine does.