I recently bought an automatic 2008 TL and under braking as it is downshifting I can feel the gears grab a bit and it makes the car buck slightly.
It's had "normal" ATF changes according to the maintenance records, only had 10k miles since last change but I was going to do a 3x3 flush anyways to start fresh. Maybe this solves the problem?
I'm curious if other TL owners have encountered this problem?
Would pressure switches fix this maybe?

 

I think what you are feeling is the standard programming of the transmission to "aid" in braking power by downshifting as you brake. Given my TL is a 6MT model I have virtually zero experience with the H5 transmission in your car, but I do know the 4-Speed automatic in the previous generation TL and the Gen6 Accord V6 were programmed to operate this way and I am assuming your transmission is as well.

 

Interesting, hopefully other 3gen TL owners can chime in.
Are the transmission fluid filters a normal service item? Wondering how dirty they get

 

Merry Christmas! Welcome to the club.
The 08s don't have a trans filter, and yes, changing the switches will improve the shifting.
A 3X3 is one of the first things you should do unless you know it was recently done.
And shoez is right about downshifting, but it shouldn't be harsh.

After you change the fluid and switches, do a reset so the trans will adapt to YOUR driving style.

 

Merry Christmas to you too!
Thanks for the insight; yeah it's not harsh but more than I think is acceptable? Ordered 2.5gal of DW-1 so I'll be doing the 3x3.
After you changed switches did you notice a difference (if you've ever done so). Or anyone else in the forum, I'm curious about your experience.

 

I do all the switches as part of the once-over when I get the car, unless I know it's been done. Pretty sure my TX bud does, too.
I've only done ONE 50K PM change-out 'cuz I don't drive so much these days, but I'd have to say that I recall a difference in the 3-4 switch a couple of times (not counting the one time I got bad switches and codes up the wazoo.) Try doing a reset first just to see if it makes a difference. The 3X3 should make an immediate improvement. Do switches if necessary or desired.

 

My 2008 TL automatic has been in the family since 30k miles when my dad purchased it (it's at 130k now). At around 70-80k miles I did pressure switches and the 3x3 service because my dad mentioned it had harsh shifts. That definitely smoothed out the shifts.

After I purchased the car (at about 120k) and drove it more I thought the shifting was harsh again. So I did the pressure switches and just a drain and fill of the transmission. It again seemed to smooth out the shifts. In my mind the pressure switches are a service item for these cars, and cheap insurance if it keeps the transmission in good shape.

 

Thanks, can you access the pressure switches by just taking the left front tire off on some jack stands?
I'm curious though why do these pressure switches go bad, they located on the outside of the transmission if I'm correct. Anyone know why they go bad?

 

Access is fairly simple, vids are available. Everything eventually goes bad. That's life. The switches slowly wear out and the trans shifts slower or harder. I haven't encountered any "sudden failure" on them. Replacing them is just to keep the trans shifting smoothly. PM.

 

couple things to correct here.


1. 07-08 TL does have the trans filter, however it located inside the bell housing. You will have to remove the trans from engine block to gain access.

2. 3x3 help elevate the hard shifting but not eliminate completely. Type S shift harder than Base model especially from 3rd to 4th.

3. I actually did 5x3 prior replacing pressure switches and the hard shifting almost gone completely.


As far as why the pressure switch goes bad you can perform a Google search, I had written a thread provide detail about it here on AZ.

 

Absolutely. Merry Christmas to you and yours!

 

I would clean the solenoid screens, replace 3rd and 4th gear switches and do the 3x3 drain and refill with new DW-1 fluid. Buy a case at your local honda dealer (12 quarts) and you'll save some $$$

 

Depending on terrain, but the grade logic programmed transmission at times will downshift and feel like the brakes
have been applied, especially when slowing, perfectly normal.

 

pressure switches, solenoid screens, trans filter, a 3x3 and maybe gear position sensor and you should be good. if its really bucking then maybe the clutch packs have worn but i would hope not. how many miles?

 

And you have a 2007 or 2008 automatic base TL? Yeah it definitely feels like it's the way it's programmed, it downshifts into each gear when I'm coming to a stop.
yeah I also drive a Honda pilot which has a similar transmission which is smooth as butter on down shifting.

 

I have done the 3x3 and it has improved for sure. Waiting on the pressure switches to change those out. Like someone else mentioned, the trans filter is inside on the 2008 models. It's only got 122k miles and the fluid was relatively clean looking and not much metallic parts on the drain plug when I changed it.