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Path_0_logical

Annoying jolt when accelerating moderately past 2000rpm

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Hey all, so I noticed that my Pathy has this thing where when I'm accelerating moderately past 2000 rpm after a few seconds the RPMs drop about 500-1000 and there is a noticeable 'jolt' when the RPMs drop. I guess this may be the automatic transmission downshifting past a certain speed/RPM but I just wanted to confirm, and see if you guys know a way to make the jolt less rough. I had a recent oil change and transmission fluid change, and also did the whole Seafoam through the vacuum line thing to clean the engine.

 

Let me know what you guys think. Cheers.

P.

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Sounds like a hard shift to me. Any codes? The diagnostics for shift shock in the '03 manual suggest checking the accelerator pedal position sensor, line pressure, control valve assembly, various clutches and bands, and (if it's just from first to second that's harsh) the trans fluid temp sensor. I'd start by checking the pedal sensor because it's the one thing on the list that's not in the transmission. Looks like it's got two sensors inside. I would assume one is for the engine (drive by wire) and the other tells the trans computer how hard to shift and when, but it looks like both go through the ECU, so I could be wrong (maybe they're redundant in case one fails).

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Posted (edited)
43 minutes ago, Slartibartfast said:

Sounds like a hard shift to me. Any codes? The diagnostics for shift shock in the '03 manual suggest checking the accelerator pedal position sensor, line pressure, control valve assembly, various clutches and bands, and (if it's just from first to second that's harsh) the trans fluid temp sensor. I'd start by checking the pedal sensor because it's the one thing on the list that's not in the transmission. Looks like it's got two sensors inside. I would assume one is for the engine (drive by wire) and the other tells the trans computer how hard to shift and when, but it looks like both go through the ECU, so I could be wrong (maybe they're redundant in case one fails).

 

 

Hmm yeah a hard shift could be the issue. So far no codes related to this issue. For now I only see this in drive gear. In drive gear with overdrive off and flooring it (pretending I have a G35 turbo lulz) there isn't really any abnormal roughness, the other gears work fine as far as I can tell. I'll try checking the sensors you mentioned.

 

Cheers.

Edited by Path_0_logical

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Posted (edited)

If it’s not the transmission, I’d guess the driver’s side motor is split. Symptoms read like my buddy’s...it was basically the motor lifting from torque, and when torque dropped enough from transmission shift, the engine was dropping back down on the mount. Most noticeable in the 1-2 shift. 

Edited by hawairish
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I added half a quart of Seafoam Trans Tune and it seems to have dampened the jolt somewhat. As far as a cheap fixe goes, I think I'll stick to changing the fluids and see how it goes. Speaking of which, the next scheduled maintenance would be to change the transfer case and rear diff fluid.

 

Cheers.

P.

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My ex's 01 Quest was starting to slip between shifts at wot, I started changing the trans oil every time I changed the engine oil and it fixed the problem. There's no filter to replace. I just drained the pan, and then topped it back up. It went another 60K miles since I started that with no problems. It was still going strong when the dumb bitch parked it because the alternator quit around 200K miles! I do the same with my titan now, I just have to buy the special oil for it instead of picking it up at walmart.

James

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Tell us how you really feel, James!

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There's not enough room on the new server for that story!!

James

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