08 jeep GC, slight mpg improvment

[meep]

2008, 3.7L 3.05 rear, 5spd wa580 trans. 25000 miles.

stock mopar (valvoline?) atf+4
stock mopar 75-140 syn gear lube.

swapped in 6 qts of Castrol ATF+4. wanted to use amsoil but it's got the lifetime powertrain warranty so I stayed in spec. Castrol had the closest vi and pour points to amsoil that I saw. oem fluid came out red-brown through the suction hose, looked DARK in the jug, didn't smell burnt (I drive it pretty easy) but smelled very dull compared to that normal atf sharpness.

swapped rear to M1 75-140 syn. oem came out yellow-gray, in the hose, grey in the jug.

trans used to be sluggish into reverse. delay is now much shorter. 1-2 shift is snappier.

Car "feels" different... can't describe how. kids in back said it was quieter.

the BEST avg mpg I could achieve since new was 22.5 on my commute, really trying. I hit 24.0 last week, really trying.

Hwy mpg with air was 21 mpg, now 22, round trip total.

yay!

 

[demarpaint]

Nice, I'm wondering does your Jeep have a dipstick? If not how did you check the fluid? I have no dipstick for my 08 Liberty just that stupid plug. I bought a dipstick from an 06, the last year they had dipsticks. I haven't gotten around to trying it. They certainly made it hard for the DIY'er to check or change the fluid.

Thanks!

 

[meep]

I waited until the engine cooled to ambient temp, 100°F, then sucked the atf out with a mityvac extractor, which has graduated markings on the can. Was able to remove just under 4 qts. So I put just under 4 back in. Ran it through the gears, sucked out an additional 2. Put 2 in.

I thought of making a dipstick out of a LONG white zip tie or some such, but this was easy enough.

Agree-- I've heard they did the dipstick delete b/c the trans is extremely sensitive to oil levels, but that doesn't make sense to me, as the level fluctuates with temperature anyway.... who makes an AT that is sensitive down to 1mm? The temp/measure procedure is an added PITA.

Odd though-- they quote 6 qts for the trans service.... so I was very surprised to only get 4 out by pump, and the pump tube made it all the way to the pan...

M

 

[rslifkin]

When you pull the pan, some will drip out of the valve body while you're cleaning the pan and changing the filter. Just sucking the pan dry doesn't get quite as much out.

 

[meep]

yea... but 2 quarts? I let it sit for 15 minutes then applied additional suction-- got additional 1/4 qt.. wonder if the FF was low? If it had a dipstick.... Thinking I'll go make one. Miller Tools wants $60-70 for the real one. grr.

 

[rslifkin]

It could have been low to start with, and in some cases, a decent bit more comes out once the filter is pulled, which, of course, doesn't happen with the pan still on.

 

[meep]

^^ yes. filter could hold a bit in it, and the quicker shift into R could be a fluid level item, low FF, fluid level lower when cold... it all jives. I guess I need to stick a tube, zip tie, piece of wire down there and measure actual level to verify.

Go Team!

I love the discussions that are REAL and don't bash X, Y, or Z.

M

 

[demarpaint]

I was going to do the same thing, remove via the dipstick, then measure and replace. My Jeep is pretty new [13,000 miles]. I'd like to drop the pan at 15,000 miles, clean it, remove and replace the filter, fill with new fluid. Then at that point draw it out via the dipstick once a year.

I might have a local reliable tranny shop do the pan drop and calibrate my dipstick from the 06. Or maybe in the fall do it myself.

 

[meep]

I've heard you need to be very careful re-torquing the pan bolts as the casing is soft AL and strips easily.

If you KNOW the level is right and then suck it out thoroughly, then you'll know exactly how much to put in every time you do a thorough pump-out. If mine was low from factory, it's low now... but it's running great.

The manual suggests 100,000 for "normal" service and 30 for severe. I am very easy on this vehicle on and occassional off-road with mild towing. But the fluid was def darker when it came out. I really think this trans will do better with the old-fashioned 30,000 fluid changes, if not more frequent.

I really like the feel of the castrol +4 vice the FF valvoline.

M

 

[santov]

I had a speed up in P > R times too. I bought a dipstick from eBay for ~$25, it was worth it. I discovered my transmission was grossly overfilled, had I put in the same amount I took out I'd still have the wrong amount. It was worth dropping the pan so I could clean the gunk off the magnet and change the filter.

 

[meep]

hmm. I will eventually do a pan drop... but suspect the filter is fine at this mileage. is it a media filter or just a screen?? There's a magnet in the pan?

Mikey!!