shift points change with fresh fluid/filter?

[AZjeff]

Just serviced the transmission on my "new" 69K '06 Jeep GC with a new OEM filter and 3X 4qt drain/refill of Valvoline ATF+4. I'm convinced it upshifts sooner and holds the gear longer before it downshifts. Is this possible/normal? Driving the same road at the same speed I know where the shifts are and it's different now. The old fluid had 50K due to warranty work at 19K, the pan was clean with very little deposit on the magnet. The service was flawless and while the pan was off I had my son weld a bung on so now drains are easy!

 

[beast3300]

Adaptive transmission, it can change fairly quick to changes in driving style. Sometimes with new stuff the driver may change their throttle positions to favor/try out new fluids etc.

 

[AZjeff]

Running on cruise control at same speed.

 

[dparm]

I guess if the original fluid was horribly broken down and thick it MIGHT shift a tad differently. Or if it had something ridiculous like straight-90 and you changed to 75w90.

 

[AZjeff]

The fluid was replaced by a Jeep dealer under a warranty repair, one would have to assume they used ATF+4. It didn't look thick, slightly darker than new is all. Must be imagining it.

dparm, just replied to your handgun post.

 

[ltslimjim]

Sounds like it's working right to me and old fluid vs. new fluid will always have a reaction from the TCM in adaptive automatic transmissions.

 

[unDummy]

If you can feel a noticeable difference with new ATF, you went too long on the old ATF. Practice a more frequent drain/refill or exchange interval.

 

[ltslimjim]

Originally Posted By: unDummy
If you can feel a noticeable difference with new ATF, you went too long on the old ATF. Practice a more frequent drain/refill or exchange interval.


I'd tend to agree here.

My older Stratus recommends every 30k.

 

[AZjeff]

Originally Posted By: unDummy
If you can feel a noticeable difference with new ATF, you went too long on the old ATF. Practice a more frequent drain/refill or exchange interval.



That's good advice unDummy. Thing is I just bought this Jeep. It had warranty transmission work at 19K with new fluid, it has 69K on it now, the manual calls for 60K service so I'm 10K early but want to start my ownership all fresh. Thought I made it clear in the OP it was a "new" used Jeep, sorry.

I don't know much about adaptive transmissions so that must be it.

 

[widman]

60K is way too long.

And remember you only changed less than half of it. Repeat after 1000 miles or so.

 

[AZjeff]

Originally Posted By: widman
60K is way too long.

And remember you only changed less than half of it. Repeat after 1000 miles or so.


So we think that factory OCIs are too short but transmission service intervals are too long?

I drained/filled 3 times using 12 quarts, some complicated math tells me I've got slightly over 75% new fluid in there and a new filter. It's greatly diminishing returns now, every quart I dump now contains 75% new fluid. What's your service interval for auto transmissions?

 

[ltslimjim]

Chrysler/Dodge/Jeep transmissions used to be on the side of needing 30k intervals. I'm sure the newer transmissions that came with ATF+4 instead of ATF+3 are a little more lenient, depending on transmission. My 99 has the 41te transmission, it still has some ATF+3 in it. I'm having to add some LubeGard to mine on top of Valvoline ATF+4 because of the difference in the two fluids(old gummy ATF+3 with 4 quarts of ATF+4 currently). I hope to be able to get it all out when I get more service done to the car later this week. It wasn't serviced until 100k miles either, so I'm having to take more drastic steps, since the torque converter is giving some symptoms as well. The Haynes manual says every 30k, some cars say 'first change' at 50k etc, but then every 30k after.

 

[widman]

Originally Posted By: AZjeff
Originally Posted By: widman
60K is way too long.

And remember you only changed less than half of it. Repeat after 1000 miles or so.


So we think that factory OCIs are too short but transmission service intervals are too long?

I drained/filled 3 times using 12 quarts, some complicated math tells me I've got slightly over 75% new fluid in there and a new filter. It's greatly diminishing returns now, every quart I dump now contains 75% new fluid. What's your service interval for auto transmissions?


I use the machine to do the changes, so I get 100% each time. Conditions vary, but most transmissions that come in with 30,000 to 40,000 KM are burnt smelling and dark.

I normally recommend 30,000 km on group II Dex/Merc and 40,000 to 50,000 km on synthetic Universal.