2016 8 speed Tranny - gear hunting after 100K miles and fluid change

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rscoleman

rscoleman

Joined
May 15, 2018
Threads
16
Messages
468
Location
Round Rock, TX
Not sure if I am imagining it or actually have some gear hunting issue. What I am noticing is 7 to 8 up/down shifts over same roads at same speeds that I did not notice 20K miles ago. Few things of note I change to 10w30 oil at 90K. I had transmission fluid replaced by dealer at 100K. I just past 110K and changed oil this past Wednesday. On most recent trip back from Southeast TX to Austin I noticed some gear hunting 7 to 8 running in 85 to 90mph range. Anyone else with 100K plus miles on 8speed having any similar issues?
I thinking of running back to dealer and having them confirm fluid level that I am not low. Any other suggestions?
I do tow monthly but only about 3000lb of boat. I recently towed a boat back from Missouri it was little less than 2500lb. I ran 7th as highest gear for that trip home and it was after the 100k service.
 
Obviously hard to say whether something is going on. Checking the fluid level in the trans is always a good thing.

Must say at 85 to 90 mph I am not surprised it does not hold 8th gear. I typically go 70 to 75 and without head wind and going flat it stays steady in 8th, however any bridges it will often switch back more so than other cars I have driven. I do have stock tire size for now and a rhino roof rack, which will create some more drag. Any mods recently which can result in this? Perhaps head wind conditions? Obviously 15 mph or more head wind makes a big difference.
 
Engine oil weight would not affect this so let’s remove it from the list of potentials.

Is the highway at speed between 80-90mph the only place you are experiencing this? You mentioned this scenario sort of separately from the towing so I’m just trying to make sure when the issue is happening.

If it’s only on the interstate at those speeds I can’t say it’s unusual. Could you have been experiencing a headwind at this time?

The trans fluid change would draw attention since you think you’re experiencing a difference in shifting since this service but if it’s never been done before I don’t think it’s crazy to experience a difference in it’s shifting characteristics. Was this the first fluid service on this transmission? Do you track the torque converter and pan fluid temps while towing it driving? Some more detailed data while driving could shed some light on things. Also, double check the fluid used during this service and make sure is the ATF WS. Checking the level for isn’t simple like pulling a dipstick so there’s room for error there as well.

All this to say that some more data points would help. At 80-90 mph the wind resistance alone could cause some down shifting to maintain that speed, especially if there’s a headwind so don’t panic.
 
So no mods stock LC200 running Nitto Terra Grapple G2 with 50k miles on them.
Can not say I notice this at lower speeds I usually have cruise set between 85 and 90 running 290 Highway between Houston and Austin it is rather hilly road. Just can't remember this issue before the fluid change.
Yes it could have been windy as it often is on this drive.
Yes first time I changed trans fluid was 100k.
I do not have any software for tracking real time trans temps or anything above what LC will display on dash.

Will schedule a service visit and confirm what fluid was used and confirm that level is correct. Dealer did all the work so they should check there work.

Thank you all for the feed back I will update after I get it to dealer. I use Cedar Park Toyota.
 
rscoleman said:
So no mods stock LC200 running Nitto Terra Grapple G2 with 50k miles on them.
Can not say I notice this at lower speeds I usually have cruise set between 85 and 90 running 290 Highway between Houston and Austin it is rather hilly road. Just can't remember this issue before the fluid change.
Yes it could have been windy as it often is on this drive.
Yes first time I changed trans fluid was 100k.
I do not have any software for tracking real time trans temps or anything above what LC will display on dash.

Will schedule a service visit and confirm what fluid was used and confirm that level is correct. Dealer did all the work so they should check there work.

Thank you all for the feed back I will update after I get it to dealer. I use Cedar Park Toyota.
Click to expand...
If it was a dealer, they (hopefully) used the OEM WS trans fluid, so the fluid type should be uniform across the dealer network. Unless they're using some BG stuff which some dealers/owners swear by for transmission fluid servicing (I have no experience with BG products). I'd be curious about the level maybe being low as you're considering too.
 
I'm not as convinced this is a problem with the transmission/ fluid. Usually the transmission is in lockup at those speeds. I would just as much suspect this is a fuel problem where the engine ECU was pulling timing and not making as much power as normal. Could also be something like a dirty air filter.
 
GrouchyTech said:
The transmission memory is where your transmission’s wear values and driver adaptations are stored. Resetting is worth a try.
Click to expand...

I was under the impression that the transmission memory would reset by simply disconnecting the battery for a period of time - no GTS+/Techstream necessary. Is that not the case?

TIA
 
gaijin said:
I was under the impression that the transmission memory would reset by simply disconnecting the battery for a period of time - no GTS+/Techstream necessary. Is that not the case?

TIA
Click to expand...
No, the idle learn, fuel trims and similar can be wiped with a long battery disconnect, but the transmission values persist. They ARE constantly updated, though. I don’t know details beyond that, though.
 
rscoleman said:
Not sure if I am imagining it or actually have some gear hunting issue. What I am noticing is 7 to 8 up/down shifts over same roads at same speeds that I did not notice 20K miles ago. Few things of note I change to 10w30 oil at 90K. I had transmission fluid replaced by dealer at 100K. I just past 110K and changed oil this past Wednesday. On most recent trip back from Southeast TX to Austin I noticed some gear hunting 7 to 8 running in 85 to 90mph range. Anyone else with 100K plus miles on 8speed having any similar issues?
I thinking of running back to dealer and having them confirm fluid level that I am not low. Any other suggestions?
I do tow monthly but only about 3000lb of boat. I recently towed a boat back from Missouri it was little less than 2500lb. I ran 7th as highest gear for that trip home and it was after the 100k service.
Click to expand...
Were you using cruise control? At those speeds and with hills or wind, the cruise programming will definitely cause some gear shifting.
 
GrouchyTech said:
No, the idle learn, fuel trims and similar can be wiped with a long battery disconnect, but the transmission values persist. They ARE constantly updated, though. I don’t know details beyond that, though.
Click to expand...

Helpful, thank you.
 
Gas was one of my thoughts although I am consistent with my gas stops being the Buc-ee's in Giddings, Waller, Baytown. I should make it to dealer before I run the same route again in 3 to 4 weeks. FYI no issues in around town, to grocery store, to dinner, etc...
 
Made it to dealer on Friday. I was about 1/2 quart low so I doubt that was issue. I have never done a fuel system service they recommend that and I was already there so I had them do that. I got another trip to parents next weekend so see if hunting issue is still there. 15K more miles till front and rear diff fluid and transfer case change. 40k till transmission fluid again and coolant. I will likely replace radiator, water pump, thermo, all pullies, tensioners etc... at that 150K service.
 
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