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-   -   Odd idle when shifting... (http://www.jeepgarage.org/f5/odd-idle-when-shifting-1964.html)

Martyp 08-09-2009 06:13 AM

Odd idle when shifting...
 
Well, just recently (after getting the trans fluid changed a month ago) the idle has gone a bit funny.

Starting the motor its fine, sits at ~600 rpm once warmed up for a few secs, but once I shift from park to drive it dips to 400 and then bounces back to 600. It does it regardless of the engine being hot or cold tho.

Its never done this before, so I'm just wondering if any of you know what might be causing it??

Thanks! :thumbsup:

Scottina06 08-09-2009 06:24 PM

Re: Odd idle when shifting...
 
hmmm....4.7 with which tranny?

mjl2610 08-09-2009 09:53 PM

Re: Odd idle when shifting...
 
Using the mopar fluids? What other services did you have performed to the Jeep while it was there if any?

Martyp 08-10-2009 05:04 PM

Re: Odd idle when shifting...
 
Quote:

Originally Posted by Scottina06 (Post 45077)
hmmm....4.7 with which tranny?

err... According to WJJeeps its either the 45RFE or 545RFE?

Quote:

Originally Posted by mjl2610 (Post 45236)
Using the mopar fluids? What other services did you have performed to the Jeep while it was there if any?

It was done at the main dealer and Mopar ATF4+ was used. No other work was done along with it, as nothing was required.

Oddly it never done it today. Its been doing it the past couple of weeks so I've got a feeling it will return tho. :rolleyes:

Scottina06 08-10-2009 09:06 PM

Re: Odd idle when shifting...
 
hmmmm.....could be any number of things....

Intake Air Temperature (IAT) Sensor(on intake)
Throttle Position (TPS) Sensor
Idle Air Control (IAC) Motor(on TB)

check all of these for kinks in the wiring or breaks, shorts etc.

NHWK05 08-10-2009 09:16 PM

Re: Odd idle when shifting...
 
Go out and Add 1/2 to 3/4 a quart of tranny fluid to the dip stick tube to the tranny. It fixed this issue on my jeep in seconds. Buy ATF+4 tranny fluid.

BigE3 08-11-2009 05:43 AM

Re: Odd idle when shifting...
 
check the fluid level. clutches could be going dry OR the torque convertor is draining down when sitting. try letting the thing run a few minutes to let it circulate and see if it still does it.

Martyp 08-11-2009 02:23 PM

Re: Odd idle when shifting...
 
Quote:

Originally Posted by BigE3 (Post 45733)
check the fluid level. clutches could be going dry OR the torque convertor is draining down when sitting. try letting the thing run a few minutes to let it circulate and see if it still does it.

Your scaring me here! :eek:

I'll re-read the guide on WJJeeps on checking the fluid level and do that tomorrow but I would've thought the dealer would get it right - now thinking about it I don't know why; I had ATF in my diffs when I bought the Jeep!!

I always let the motor idle for a few mins before changing gear/moving. I know the oil pressure is built up in seconds but what the hell....

---------- Post added at 11:23 AM ---------- Previous post was at 11:22 AM ----------

Thanks for all the help guys! Once I've properly checked the fluid I'll report back.

NHWK05 08-11-2009 03:47 PM

Re: Odd idle when shifting...
 
For some reason jeeps with the 4.7 have strange TQ issues that can be solved by slightly over filling the tranny with atf. i dont know why but it works.

Martyp 08-11-2009 05:40 PM

Re: Odd idle when shifting...
 
Hmm.. So I guess even if its full and I add a 1/2 quart of extra fluid it won't hurt anything??

I mean if you add to much oil to an engine it causes issues, but I assume the tranny is different?

NHWK05 08-11-2009 06:08 PM

Re: Odd idle when shifting...
 
Yes, thats been the issue is that the tranny needs just a bit more fluid to build pressure, this tip came to me from a master jeep tech. I did it after questioning it for weeks and it worked perfectly. 1/2 to 3/4qt wont hurt anything.

BigE3 08-11-2009 06:52 PM

Re: Odd idle when shifting...
 
Quote:

Originally Posted by Martyp (Post 45895)
Your scaring me here! :eek:

I'll re-read the guide on WJJeeps on checking the fluid level and do that tomorrow but I would've thought the dealer would get it right - now thinking about it I don't know why; I had ATF in my diffs when I bought the Jeep!!

I always let the motor idle for a few mins before changing gear/moving. I know the oil pressure is built up in seconds but what the hell....

---------- Post added at 11:23 AM ---------- Previous post was at 11:22 AM ----------

Thanks for all the help guys! Once I've properly checked the fluid I'll report back.

Ever since 94 jeep has been putting a 1 way check valve inline to prevent the torque converter from draining down. If you ever put it in gear and it just sits there for a few seconds and it just bumps. you got an issue that needs to be fixed. either fluid, clutch, pump, tc, cv,etc...

and as far as dealers are concerned. always find out what they are supposed to do so you know what to look for after they are done doing it.
a friend of mine that used to work @ Jeep and people would bring in their lease cars for oil changes and etc. you'd be horrified if i told you that some jeeps wouldnt get oil changed till almost 50k miles. sure they would put on a new filter to make it look like its been done. so the reason they would ignore the car is because it doesnt make them any money doing warrenty work. so from now on. DIY


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