Need advise on 04 r48e problem

[BSchulte]

I am still having problems with my trans not shifting (continuosly) into over drive. It seems to have a lazy shift before going to OD. Torque converter seem to unlock but then goes back to 3rd. until 45+mph is reached, then goes to OD. Had it at the dealer twice to check it out. They say it's the way it is, and don't see any major problems.

I read a older post descibing how to adjust the APPS (Accelerator Pedal Position Sensor) This described how to disconnect the batteries for 30 minutes, turn the key to run, depress the accelerator slowly, then turn the key off. This was explained to radjust shift pattern.

Is this true for 3rd. Gen R series trannys?

Help?

 

[txhawg]

Mine won't go into overdrive until 51 MPH. I thought that was normal

 

[DJamrose]

same here around 50 she goes right in

 

[Rams-n-Hogs]

Same here - between 45 and 50. I would think that was normal.



Jim

 

[BSchulte]

Sorry for the mistake in question.

"It doesn't always shift into OD @ 45mph. "

The torque converter disengages always @45-48. But, sometimes shifts back to 3rd. until the truck get's to 55.

Sorry for the confusion.

Based on this, Any thoughts on my original post?

 

[yycguy]

Sorry for the mistake in question.

"It doesn't always shift into OD @ 45mph. "

The torque converter disengages always @45-48. But, sometimes shifts back to 3rd. until the truck get's to 55.

Sorry for the confusion.

Based on this, Any thoughts on my original post?

That's about the way mine works! IMHO seems normal for a 4 speed auto

 

[Wal_mart]

Friend had similar symptom. Got to where it would not go in OD. 2004. 5. Dealer changed valve body

 

[WoodChuck]

I think that most of you guys are mistaken on the shift pattern on the 48RE. The "shift" you feel at 50 is the torque converter locking not the transmission shifting. For proof pay close attention to your tach at about 45 and slightly let off and then slightly press the go pedal and you can see the change in RPM without much change in road speed. Then after it locks above 50 try the same thing and you can tell the engine is locked to the axles without slippage in the converter.



Something interesting I've noticed is that once the converter locks at about 50, you can set the cruise control then decell as slow as 35 mph and it will stay in 4th lockup. If you keep the cruise on and hit the accell button it will accelerate in 4th lockup.

 

[Bill Stockard]

Something interesting I've noticed is that once the converter locks at about 50, you can set the cruise control then decell as slow as 35 mph and it will stay in 4th lockup. If you keep the cruise on and hit the accell button it will accelerate in 4th lockup.

Yep, I used that trick when I had my '97 CTD w/auto and a PacBrake on it. The downside was that I couldn't shift down to a lower gear while the torque converter was locked.



Bill

 

[BSchulte]

Tri Guy.

Wow interesting discovery!

Does any one know about the APPS as I described earlier?

Is this a function on a 3rd Gen. truck?

I'm not too confident with my dealership's mechanics.

If I changed to an aftermarket torque converter, would the trans act the same way?

thanks for your reply's thus far

Brad

 

[OT-OF-HERE!!]

48RE shifting problem

I'm don't think this situation is normal,... it only happens with a box on the truck. At WOT when it shifts from 3rd to OD there is a delay that seems to take a second or two for the transmission to lock up. That's happening somewhere around 75 to 80 mph. With the box off it doesn't do it. I'm putting an ATS TC and a custom VB on next Friday and raising the pressures internally in the transmission. Will let you know how that works for eliminating the problem.

 

[WoodChuck]

I don't know about APPS but I cant see how doing anything with the key when the batteries are disconnected would do anything. I've read about disconnecting the batteries and cleaning the terminals helping the 2nd gens with shifting problems.



It sounds like your trany is working normally. If you only change the torque converter the operation will be the same as before only you'll have more holding power before the converter slips while in lockup mode. Something you really don't need unless you've bombed the engine.



If you have bombed the engine the next thing to slip under extreme loads would be the clutch packs inside the transmission (of which there are three).



Changing the valve body too would help with slippage to due to increased line pressure.