Hard 4th to 5th shift

I've read on other threads people getting a reflash of the trans on their 13s and 14s and some saying that they may have come from the factory with low fluid.

 

My '15 will sometimes have a very slightly clunky 4th to 5th shift but only under specific conditions. But it's never been very bad at all.

1. Cold temps, below 50°F, but especially in freezing temps and the transmission has to be cold as well.

2. Light throttle being applied. If I'm a little deeper into the pedal it's less likely to not do it.

If the outside temps are warm/hot I tend not to experience it, even if the transmission is cold.

So what I do during cold weather....is I simply leave it in 4th gear. After a few minutes to warm the transmission up I shift back into drive without issue.

In fact, if I'm driving in the city, I tend to leave it in 4th gear regardless of conditions. My speeds are typically under 45 mph. The rig is more responsive and there's no race for it to get to 5th gear.

 

I can relate to this to a T. Exact same experience. I do the same thing now with using 4 around town and D when going above 50.

 

Thankfully it's never been a real issue for me. Any clunky 4th to 5th shift I've had been minor compared to what others have reported.

I think it's just the nature of the A750 transmission. And despite what some claim, low fluid level and old fluid are not the reasons. My fluid level was spot on and I've done several drain and fills for the years....so the fluid is in great shape.

It's just a quirk. Not a problem.

4th gear is the answer if it's bothersome.

 

My 2014 w/109k does this when the temps drop into the low to mid 30's or below after a cold start. Above 40 it's smooth. Most noticeable at light throttle as when going down a gentle hill near my house. About one mile or so later, it's gone. I leave it in 4th for five minutes or so if I notice it and it's gone.

It's an Aisin Seiki transmission: I'm not worried about it. It's kinda old school, which I'm fine with, so it's not going to shift like the newer ones; it also doesn't hunt all over the place trying to make up its mind like some of the newer ones either. I had four Volvo's with 4 speed Aisin automatics. I put 200+k on two of them and 190k on another and currently have 157k on a 1998 S70 GLE-SE Intercooled 5-cyl Turbo. (It doesn't live a quiet, sedate life: too much fun to drive.) I towed a nice-sized pop-up with all of them. Not one issue on any of them. With the exception of the S70, I put external B&M stacked-plate external transmission coolers on all of them. (Same cooler on a Blazer and Bronco that I also had over the years.) Fluid all looked cherry-red with those coolers, but with the Aisin transmission,

I came to believe the Aisin transmissions didn't really need them. The Ford (FMX): maybe. The Chevy 700R4: absolutely: even with a tow pkg which on that truck, amongst other items, included a power steering cooler, a heavy duty transmission cooler in the radiator side-tank and an external engine oil cooler.