48re shift problems

SPEEDSHIFT

SPEEDSHIFT

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Jan 30, 2007
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I just rebuilt my 48re and I am having some problems with OD engaging at the right time. I have a transgo shift kit, sonnax billet accumulator, servo cover, servo piston, 3.8 apply lever, and my tv is maxed out.

If I run the cable loose I get a bad 2-3 shift and if I run it maxed it won't shift into OD at wot or it goes from 3rd to OD then back to 3rd and finally OD again and stays. I have yet to put a line pressure gauge on it, but it is in the works.

One thing I was unsure of, is if I should have used the stock accumulator spring with the billet accumulator... Idk
 
Is the TV used to command a OD shift though? I didn't think it was.
 
I'm thinking it may need the throttle valve rebuilt. I noticed it didn't have much travel when I had it out. Had about a half inch of dead area before the lever touched it.
 
Give Goerend a call! Jeff or Dave will give you a good bit of advice on that issue!
 
SPEEDSHIFT said:
I'm thinking it may need the throttle valve rebuilt. I noticed it didn't have much travel when I had it out. Had about a half inch of dead area before the lever touched it.
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Half inch of cable movement? My 47rh probably had about that much also.


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Like a half inch gap from the tv lever to the actual throttle valve on the vb.
 
Yep. My 47rh was the same as that. Now I have this 48re and have a v2. I've been trying to get the transmission tuning where I want it for a while. O/D seems to not respond to tuning. It engages whenever it feels like and doesn't follow the tune. I'm beginning to think I might have a possibly hardware problem as my actual/demand pressure and such are very different. Sorry not sure I'm helping though.


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Ghostman said:
Yep. My 47rh was the same as that. Now I have this 48re and have a v2. I've been trying to get the transmission tuning where I want it for a while. O/D seems to not respond to tuning. It engages whenever it feels like and doesn't follow the tune. I'm beginning to think I might have a possibly hardware problem as my actual/demand pressure and such are very different. Sorry not sure I'm helping though.


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Click to expand...

I don't know how much the transmission tuning will do, from reading, not personal experience. I believe modifications to the valve body and transmission will be more effective than tuning/software.
 
ramthiscummins said:
I don't know how much the transmission tuning will do, from reading, not personal experience. I believe modifications to the valve body and transmission will be more effective than tuning/software.
Click to expand...


I was at least hoping I could get 3rd gear to carry out further before shifting to fourth.

I guess maybe the truck doesn't follow the tune to the tee or actually I know it doesn't. Maybe this is just how it is, idk? Can't get an expert to weigh in on it.


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Ghostman said:
I was at least hoping I could get 3rd gear to carry out further before shifting to fourth.

I guess maybe the truck doesn't follow the tune to the tee or actually I know it doesn't. Maybe this is just how it is, idk? Can't get an expert to weigh in on it.


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Click to expand...

Just to shed some light, I have been able to do plenty of transmission tuning on my rig using HP Tuners, up to and including extending the shift point RPM at WOT to 4K RPM for 1-2, 2-3, and 3-4 gear.

TCC Lock-up and Release is also functioning as expected.

Dialing in the TV motor settings is proving to be a little challenging to find the sweet spot (2005 truck), but it is responding to changes.

If you are using HP Tuners software for the tuning, be aware that they have the tables improperly labeled. Other than "WOT Upshift Force RPM" and the 2 Error parameters that follow it (WOT Upshift Error HI and WOT Upshift Error LO), it isn't input shaft speed that these tables reference. They reference output shaft speed.

One of these days I hope they figure that out and fix it.

Sorry, SPEEDSHIFT. I know none of this information is relevant to the issues you're experiencing. I hope you do get them figured out, though.
 
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I have HP tuners as well, maybe I can tune it to shift right? I don't have a table for 2-3rd though. Just 3-4 shift.
 
SPEEDSHIFT said:
I have HP tuners as well, maybe I can tune it to shift right? I don't have a table for 2-3rd though. Just 3-4 shift.
Click to expand...
Yeah, there is no table specifically for defining the 1-2, 2-3 shift points. You can sort of adjust it by playing with governor pressure ramp, and in the case of 2005 trucks, you can play with the electronically controlled TV motor vs throttle settings to change things up.

But what I found to make the biggest difference for 1-2, 2-3 shifts was adjusting the "WOT Upshift Force RPM", and the "Error Hi/Error Lo" parameters accordingly.

I don't know if those tables/parameters exist in the 04 calibration, though.
 
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