I have an 03 HO 48re, since new till 50k now, when shifting into OD at moderate throttle it will slam into OD. Now with light throttle or half to wide open thr., it shifts perfect. With that said I have installed a triple lock converter, and it has magnified the harshness at moderate thr. I assume it is because there is probly zero slippage in lockup. My only concern is breaking an input shaft or something else, is this possible? Also is there any kind of adjustment or reflash that could come it down. I have flushed it once before the converter, and again when new converter was put in. I have always controlled it with my foot, but when I'm pulling my goose or bumper trailer I forget sometimes. Is this a problem that a V.B. could help with?

 

Guess nobody has any input?

 

Was hoping someone would have something to say about this also. Mine is stock and does what you describe: seems to want to shift into OD and lock up the convertor at the same time, but only if you are part way into the throttle. Lean on it harder and it holds the shift longer, smoother. Back out of it a little before it wants to shift, and it slides in nice. I don't think there's anything wrong with it that will cause premature wear or anything, but it is kind of annoying. Planning to try a trans. fluid change in the spring to see if it makes any difference.

 

Exactly Tim, I was just curious if there was anyone out there that did converter that had this so called problem. Then if maybe they tried a VB and if that helped any.

 

what's a VB?

 

A VB is a valve body.

 

Well Tim, guess you and me got the only 2 bastards round.

 

Not that this will help much, but mine shifts erratically also, ever since it was new. I've seen this to be common on the 48re. I am glad to hear that a TC makes it more pronounced, that just assures lock up. I wouldn't be worried about wear and tear unless you are heavily modded. Just my .02

 

I think mine is like that as well. What you're feeling is 2 different events. TC lockup is one of them. Depending on throttle position/load it can sometimes feel harsh. Additionally, sometimes lockup will occur at the same time as the 3-4 shift once again depending on throttle position/load. Unfortunately I believe this is normal 48re behavoiur and I have learned to drive around it. My truck did it since new and still does it now that I'm modded.

 

When I first got my truck, I was freaked out by this but after a few people explained the events to me, I was good with it. It is even worse now that I installed a shift kit. Sometimes it is really bad but I just changed the fluid and filter again and everything looked great even with 37,000 miles and 25,000 after the shift kit. I am telling ya, if I don't pay attention to the throttle position, it will jar your teeth. Under heavy throttle or towing the race car and enclosed, it is great.

 

Mine has always done that since new also. At 45000 I had the fluid and filter changed. The tech also upped the line pressure some and adjusted the TV cable. I hardly ever does it now.

 

I think maybe the reason you're not getting a lot of responses to this is that not everyone notices, for whatever reason. I've owned noting but sticks for as far back as 20+ years...the quirkiness of the auto sticks out like a sore thumb for me no matter who's auto I'm driving. Driving a stick regularly (regardless of platform) tends to give you a "feel for machinery" that an auto can sometimes shield you from. That said, the 48RE needs work to feel in sync with the CTD.

Just seems to me that the TC and valve body doesn't seem to agree with the CTD. They're essentially on a different page. I think therein lies the beauty of the Duramax/Allison combo...

It's not the HP potential of the LBZ, but the tranny's ability to know what the engine is trying to do. All that said, I think the 48RE/610CTD combo, has more potential....as soon as one of us figures the darn thing out

Pure HP aside..... build HP that the tranny knows how to use, and you'll have one wicked animal.

 

I thank all of you for your responses. I was thinking exactly like BigGunZ. Buddy's Ram, you say upped line pressure and Tv adjust, these 2 things helped quite a bit then? I've drove and rode in a few other 03 and newer trucks, but never felt it in them. Kinda glad this is pretty much normal. thx again. The only things done to mine is TS mp-8 , 4" turbo back, AFE intake, and the converter. It's a 4x4 dually, and the more I think of it the 3.73's could be more pronounced than a truck with 4.10's?

 

I've driven a few 48re's and I like the quick, firm shifts. There's not much slipping going on and it goes to lock up pretty fast. I don't know that much about automatic transmissions but it seems to me this would reduce heat build up. The 47re I have now is slushy in comparison ....if I had my choice between the two it would be the 48.

 

It's only bad at say 1/4 throttle. Think of like this, if you were driving a 5 speed and shifted from 4th to 5th without the clutch and without letting of the throttle thats what this would compare too. I road in a friend of mines 03 today with a Suncoast in it and it shifts the same. What I did do today was adjust the TV cable and that seemed to help so far. I adjusted like the old TH350 and 700r4 that GM used, 2 people is easier. Have someone hold the throttle on the floor while you remove the white plastic retaining clip on the cable carefully, and pull the cable housing toward the firewall till the cable gets snug and reclip it while holding it.