When accelerating moderately to heavily, and with the OD NOT locked out, the TC will lockup while still in 3rd gear once the truck reaches ~47mph. Then, when the speed of the truck combined with the position of the accelerator dictates upshifting into OD, the TC will unlock, the tranny will shift into OD and the TC will re-lockup. These last 3 sequence of event happens very quickly - less than 1 second. Doing so sometimes creates quite a shudder in the drive. Basically, I'm wondering if this is normal? It was my understanding that the TC shouldn't lockup until OD is reached if the OD is not locked out.

I hope I have given a good enough description to explain what is going on.

The truck has 60k miles and, to my best knowledge, it hasn't been BOMB'd in any way. The tranny is stock. 90% of my driving is commuting with the remaining 10% being pulling our 19' traveler trailer with an ATV in the bed.

Any advice/feedback is appreciated.

 

Mine does not do that.

 

doesn't the 03 have a 47r not the 48?

 

Mine does the same thing.I wouldn't call it a shuder thoe.It shifts fast enough that the T/C is unlocked for a second.It does hit 4th gear kinda hard at some throttle positions thoe.Sounds normal to me for an 04-05 truck.

 

03 47r will act like this! There is a vb and shift kit on here somewhere that will fix it. I hated my 47r in my SO 03. HATED, HATED, HATED!!!!!! I was new to the automatic when I bought the 03 and I swore that I would never buy another auto again- - - - - - - - - - but I'm happy so far with the 48r!!

 

My 47 has done that since the day I bought it. 102k with 398hp going through it and it's still ticking.

 

Is your truck a SO or HO? The HO came with the 48re. I have learned to leave the OD off until I get to around 50mph unloaded or 55 or so loaded. It helps to prevent the hunting for a gear as I call it.

 

My '04 does the same thing - always has.

 

Thanks very much for the feedback. It was always my understanding that my '03 had the 48RE but it's a SO truck so I guess maybe it has the 47RE instead. I'll have to verify that. In any case, it sounds like I'm not the only one with the described behavior so I can rest a little more at ease. Again, thanks.

 

If you have a 47RE THEN start worrying cuz that is definitely not good. If its a 48 its normal.

 

Dumb question...is there a VIN-number cross reference guide out there somewhere that I could punch in my VIN and verify which tranny I have? I have a busted up leg and getting under the truck right now to visually verify would be a real pain for me. Or is the tranny model stamped or printed somewhere on the truck?

 

See my signature. Normal operation for mine.

 

Ok, so here's a question - does my 2004 (305hp) have the 48 or the 47? I was under the impression it was the 48RE.

 

05 mine does the same thing. had it rebuilt twice by dealer, still same thing. just nature of the beast.

 

Mine does that , minus the shudder