Loss of power 04.5 LLY Duramax - Page 2

**BigRedChevy** · 07-16-2008, 08:53 AM

If you was stuck in 3rd gear you slipped the clutches during the shift. You have a couple different options. Back the power down and keep running it, you need to do this anyway until you do upgrade because it will be easier to slip since you have done it once. Your other option is a upgrade. The upgrade won't be cheap so i suggest backing the power down a little and keep running it, just watch the WOT shifts into and out of 5th gear. Either way start saving because you will need a rebuild, but you can make yours live a while longer if you back it down and go easy on it.

gr8shot · 07-16-2008, 01:07 PM

ya, what bigred said. The almighty allison will break!!! You cant just throw tons of power at it and expect it to take it forever.

They were designed to last a LONG time, but only with the stock power.

What you did like bigred said was slip the clutches in the tranny. It went into limp mode because you damaged the transmission.

If you want things to go back to normal save up for an upgraded transmission. Then you can run your programmer at whatever setting you want, and not worry about it. (there's other supporting mods you'll have to do too... lift pump, FPRV shim, and more) But the point is that the stock tranny will only handle about 90hp extra, and then it'll limp.

You just started the ball rolling downhill. Put your truck back to stock and your tranny will last a while, depending on how hard you are on it. But it won't last that long so start saving!!!

jcurry · 07-16-2008, 01:38 PM

Thanks Guys I'm A diesel Newbie. Based on these threads I think I limped my stock 05 the other nite pulling a 20ft trailor. Suddenly uphill it would not rev over 2000 even in park. Chsanged fuel filter and revved fine in park. left at midnite and it would not rev over 2000. managed to get home (slowly). Ihad a SES but After I repurged THefuel filter & runner It went away.Did the key & door thing, and now it seems fine. Do you think I did any damage.jcurry

**Meyerperformance** · 07-16-2008, 01:46 PM

if lots of smoke it could be a problem with a egr valve

gr8shot · 07-16-2008, 02:09 PM

Sounds like you had the engine limp not the tranny limp, and it sounds like it was caused by a dirty fuel filter, so most likley no, you didn't cause any damage. did you get a chance to get the SES code read? If so what was it?

luke0490 · 07-16-2008, 03:57 PM

My truck never got stuck in third gear it just would not rev above 2000 rpms each time i was climbing a hill. It happened to me twice and each time i cleared the codes with my programmer before i knew i could check the codes with it. Since then then the light hasnt come back. I just went on a 500 mile trip with my trailer hoping it would set a code off but it never did but the power is not the same.

**BigRedChevy** · 07-16-2008, 04:07 PM

If you didn't get stuck in 3rd gear then it wasn't a tranny limp. The 2000 rpm rev limiter is a engine limp most likely caused by a low rail pressure. If you was running a larger tune and had a clean fuel filter you will probably need to shim the FPRV (fuel pressure relief valve).

luke0490 · 07-16-2008, 04:16 PM

Im taking it to the dealer on monday is their anything else i should have them check? It also feels like it has more power in the begining of the haul and it seems to fade towards the end. Sorry for all the questions but it sucks when the dealer says there is nothing wrong with it when i know there is.

**mattfromwy** · 07-16-2008, 05:01 PM

Somthing must be up because i have been runing constant 7.8s with 35s on a stock tune.

jcurry · 07-16-2008, 07:41 PM

jcurry again, can i change trans fluid &filter myself or should i take to a garage? what's involved. thanks