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Discussion Starter · #1 ·
As in the title I have a 2000 jeep grand cherokee limited with the v8 in it, for some reason I can't figure out when your accelerating and the rpm's get to about 3k it seems like there's a Rev limiter and I have no power, I've replaced the throttle position censor, idle air controll censor and the fuel pressure regulator along with the fuel pump and a full tune up (plugs n packs) I need help on learning where to start next. When it does the 3k rpm limit if you let off and back on 3 times it finally will go on through and you can accelerate then sometimes it takes a 4th try and I know that's not good for my tranny or my drives haft. Help me please and thanks
 

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2001 WJ/WG, 3.1TD VM Motori. Torque- 367 Nm/271 lb-ft @ 1800 rpm
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Hi Crisco, and welcome to the Jeep family.

I've never come across this before as my gearbox changes at 2200 rpm (un-flashed 45RFE) and if I get to 3k rpm...I've never tried it before to be honest, so I'm going to see if I can get it that high on the motorway tomorrow, just to see what she does and compare to your issues. The restriction may be there to indeed protect the engine. Where does it red-line on the rpm gauge? Restrictions usually cut in about 1k revs before the red-line if I remember right, but I'm hoping others will correct me if I'm wrong as I don't want to give wrong advice and this may be regarding older engines from information read years ago.

If she used to shift no problems, then could a diagnostic reveal anything through an OBD scan? Maybe a sensor on the way out from either a speed sensor in the 45RFE gearbox or its solenoid? I've put a few posts up with schematics and issues with transmissions on other posts- look for gearbox issues in the forum titles.
Could it be a TCM issue? The TCM is referred to in the other posts, including where it's located in the engine bay for the 4.7. (4 litres work from PCM, I think?)

Anyway, good luck but I'd check the system with an OBD scan, check for any error codes and also look at the Transmission Control Module (TCM)

Keep us updated (y)
 

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Discussion Starter · #3 ·
Hi Crisco, and welcome to the Jeep family.

I've never come across this before as my gearbox changes at 2200 rpm (un-flashed 45RFE) and if I get to 3k rpm...I've never tried it before to be honest, so I'm going to see if I can get it that high on the motorway tomorrow, just to see what she does and compare to your issues. The restriction may be there to indeed protect the engine. Where does it red-line on the rpm gauge? Restrictions usually cut in about 1k revs before the red-line if I remember right, but I'm hoping others will correct me if I'm wrong as I don't want to give wrong advice and this may be regarding older engines from information read years ago.

If she used to shift no problems, then could a diagnostic reveal anything through an OBD scan? Maybe a sensor on the way out from either a speed sensor in the 45RFE gearbox or its solenoid? I've put a few posts up with schematics and issues with transmissions on other posts- look for gearbox issues in the forum titles.
Could it be a TCM issue? The TCM is referred to in the other posts, including where it's located in the engine bay for the 4.7. (4 litres work from PCM, I think?)

Anyway, good luck but I'd check the system with an OBD scan, check for any error codes and also look at the Transmission Control Module (TCM)

Keep us updated (y)
It happens only when I'm trying to accelerate on the interstate at 3000 rpm. I wish i could video it and be able to show someone exactly what I'm trying to say
 

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From what you're describing could possibly be slippage from the torque converter lock up clutch or a tranny issue.
Does it shift into the highest gear automatically?
I had a similar issue with my XJ where it wouldn't go into 4th gear. Turned out to be a simple tranny linkage adjustment.
 
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