Low power for the first few miles

CATCRD · **Posted:** Tue Sep 24, 2013 9:59 pm

Perhaps an ether mishap.

jfra · **Posted:** Wed Sep 25, 2013 11:50 am

Just got the Jeep back this morning from the transmission service. Replaced both filters and fluid. Mechanic drained it overnight and got over 10 quarts out of it but it only needed 8 qts to refill it. He advised that I keep a close check on the fluid level.

He also checked out the exhaust and said it was in great shape and shouldn't have any issues. He said if I can't get the issues that I'm having with the power solved by replacing the MAP sensor and checking out the vacuum system then we can pull the cat and check it out. He didn't advise spending the cash on the exhaust if I didn't need too.

geordi · **Posted:** Wed Sep 25, 2013 12:31 pm

The catalytic converter is not causing your power loss. If it was, it would be continuous and not 'go away after the first few miles' like an electronic problem does.

As for the transmission, if he got 10 quarts out, then he was draining the torque converter too. You will want to have at least a couple quarts of fluid on hand in the CRD to put back. Start with a full big bottle of Lucas Transmission Fix. My transmission / engine shop (going to them over 25 years) has said that nobody has ever hurt their transmission with Lucas, but it has helped performance in many cases. It is the only additive he suggests, and he recommends it for everyone. On mine, it did help with the transmission drain-back issues.

What you may discover is that the transmission dipstick is not accurate, it reads too low. The performance will be sloppy and slow off the line or at low speeds, almost like a clutch is being held half-way in, causing slip. This is almost exactly what IS happening, because the transmission needs fluid pressure to grab and hold the input shaft. Slip is bad. Slip wears off your clutch materials, so be aware if it is happening.

papaindigo · **Posted:** Wed Sep 25, 2013 12:49 pm

X2 if they drained 10 qts out then that's how much they should put back in not some lesser amount. I hope it was ATF+4 also.

jfra · **Posted:** Wed Sep 25, 2013 1:08 pm

@papaindigo and @geordi Will check the level and purchase some Lucas and some ATF+4. They did use ATF+4 in the refill.

papaindigo · **Posted:** Wed Sep 25, 2013 2:51 pm

For what it's worth tranny fluid, just like coolant and oil, amounts are not exactly to be relied on in the OEM manuals. "Service" fill (e.g. new filters only) according to the FSM is right at 5qts but forum reports in the past have said a quick in and out filter swap usually results in draining 7-8 qts with higher amounts reported coming out for longer drains especially if you have even the slightest amount of the "tranny drain back" (actually torque converter drain back) problem.

Hence my recommendation is keep track of how much comes out and put back in the same amount if for no other reason than the amount that comes out varies between vehicles and for the same vehicle depending on drain time and tranny drain back issues.

If your drain pulls some fluid out of the torque converter (sounds like yours did) and you put less ATF back in than came out then as soon as you crank up and drive the torque converter gets pumped full. When that happens assuming the anti-drain back feature is working correctly the fluid will stay in the TC resulting in an equivalent drop in the amount of fluid in the tranny pan which can cause problems.

I suspect, personal opinion, that the tranny dipstick is reasonably accurate if and only if you measure fluid level after driving at least enough to make sure the TC is fully pumped up as what the dip stick is supposed to read is the level of the ATF in the pan when the TC is fully pumped up.

Rather long winded but hopefully this makes some sense.

jfra · **Posted:** Thu Sep 26, 2013 12:19 am

@papaindigo it made perfect sense to me. I checked it hot after driving home and it was right on full. I'll check it again tomorrow am to see the cold level. I'll keep checking it for a week or so and see how it goes. It drives and shifts great. The new MAP sensor arrives tomorrow and I'm hoping it will cure what ails the crd.

If I can figure out how to attach a short video you can see the issue as it happens. Watch the MAP reading on the ScanGuage vs rpm and mph.

Edit... Apparently I can't attach a short video.

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WolverineFW · **Posted:** Thu Sep 26, 2013 12:23 am

papaindigo wrote:

Hence my recommendation is keep track of how much comes out and put back in the same amount if for no other reason than the amount that comes out varies between vehicles and for the same vehicle depending on drain time and tranny drain back issues.

Ding..Ding...Ding....the correct answer.

jfra · **Posted:** Thu Sep 26, 2013 7:45 am

Working on it @WolverineFW. If @papaindigo hadn't told me that I wouldn't have been specific with the shop to tell me how much came out. I'm getting a pretty good education on here. I appreciate the comments and feedback.

BTW.. It's been really helpful to learn the terms and part names. It has made searching the forum a lot more productive. I didn't know what to search for before so my search results weren't that great.

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jfra · **Posted:** Thu Sep 26, 2013 10:44 pm

MAP sensor replaced. Now for some miles.

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jfra · **Posted:** Fri Sep 27, 2013 1:29 pm

So far so good. The new MAP sensor is working great. The ScanGauge was very helpful in diagnosis since it displays the MAP in real time. With the faulty sensor it would drop to 0.0 at idle. Now it is reading 14 or 15 at idle and it rises and falls with RPM. It would drop back to 0.0 at every stop before.

I also think that servicing the transmission was essential. It may not have been the cause of this problem but was definitely worth it and may have prevented a future problem since I don't know when the PO serviced it and I was getting hesitation when going into reverse. I have been checking the hot and cold levels everyday.

Thanks for your input:

@papaindigo
@gerodi
@CATCRD
@bugnout
@WolverineFW
@Hexus

Low power for the first few miles

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