Jimi Hondrix

1998 Civic EX (stock D16Y8), A/T. 148K miles. Purchased 6 months ago.

Have been experiencing hard shifts in all gears since purchase. Shifts better at higher RPM's/speeds compared to lower RPM's/speeds. I did a 3 x 3 drain and fill the first week of ownership.. used Valvoline Max Life full synthetic ATF Dex/Merc and a small bottle of Lubegard red. After drain and fills the transmission did shift smoother but, not as smooth as it should. It does not flare or slip and there isn't any hesitation during launches and passing speeds,.. just hard shifts. I've been reading up on this for the past few days and through various resources online..here's a few related responses from various threads I have copied:

1) I'd guess it could be the linear solenoid (as you first mentioned) FIRST-be sure the connections for the linear solenoid are clean and corrosion free. The solenoid can become sluggish or bind with dirt/contaminants--but that again *may* be fixed by draining and filling the fluid 3x. If not, check resistance between #1 & #2 terminals on the solenoid itself. If it's between 4.0-9.0 ohms, you are within spec. If that checks out I'd check the clicking of the valve by connecting #2 to battery positive and #1 to battery negative to be sure it clicks. If it's sticking/binding/sluggish, either remove and clean the valve and the attachment channels or remove and replace.

2) check their resistance with an ohm-meter. Here are the specs.
Lock-up solenoid: 5-25ohm
Shift solenoid: 5-25ohm
Linear solenoid: approx. 5 ohm

3) The G! Acura Legend auto transmissions have the same issues with the solenoids getting clogged. Try connecting the electrical connector to the battery and grounding the soleniod body to activate the solenoid. Spray brake cleaner in the solenoid while activating the connection. Also, smack the solenoid onto a folded up towel on a hard
surface to dislodge the filings. I've done this many times on my G1 Legend auto trans and the results are incredible.

These threads touch on the possible benefits of TPS adjustment:
a) https://honda-tech.com/tech-misc-15/...e-tps-2947986/
b) DIY Modifying the stock Throttle body for more air flow

Does this sound like a good course of action:
1) Remove and clean linear solenoid, spray connections with electronic cleaner or clean and replace dielectric grease.
2) Inspect VSS (variable speed sensor), spray connections with electronic cleaner or clean and replace dielectric grease. My speedometer is not fluctuating.
3) Test TPS and report results here.
4) After posting results hack off TPS and adjust setting to hopefully improve shifts.

tony_2018

All of the above.

Former User

Given the improvement, might be worth doing a few more drain-refills with Castrol for Imports ATF.

Jimi Hondrix

Thanks for the replies. There's an Amazon review of Castrol 03521 Transmax Import Multi-Vehicle ATF from an owner of a 1997 Del Sol:
" recently purchased a 97 del sol with 154k on the odo. It was in really great condition(no modifications) and I got it for a great price but the AT shifted hard especially from 2nd to 3rd which is a common on this era of honda trans. I feared the clutch packs could be spent and I would need to get it replaced. I checked the fluid which was a dark brown probably original. I got 9 qts of Honda dw-1 and changed the fluid three times over the course of a month so it had time to mix in. The results were better with 2nd to 3rd being smoother but there was still a jolt and the torque converter clutch still didn't kick in at highway speeds. I checked the specs and while dw-1 is considered backwards compatible for older z-1 trans it has a lower viscosity and normally as a transmission ages the seals decay and requires a thicker fluid to maintain seal pressures. This is what stop slips normally do, but I've heard reviews and they can help or make the problem worse and I didn't want to take the risk. I researched other 3rd party fluids for Hondas and I saw that Castrol viscosity was slightly higher than dw-1 and z-1. Other brands were either thinner than dw-1 and some were significantly higher some almost twice as thick. I just needed a scalpel not a sledgehammer. I decided to try it and change out 3 qts for castrol in system full of new dw-1. I unplugged the battery to reset the transmission computer and after about 10 mins of driving it shifts buttery smooth. Its been about a month now and the jolt from 2 to 3 is gone, the highway speed clutch kicks in finally and the top speed has gone up from 75 to something I probably shouldn't say. I recommend you use in concert with dw-1 just to give it a little extra thickness. I hope this info helps you."

I may try it. I've also read that older Civics were known to shift fairly hard and that hard shifting is better for automatic transmissions (longevity) than soft or delayed shifts.

tony_2018

The old design was always harsh. I've heard the same.

Former User

After multiple VML and Castrol ATF drain and refills, my 00 Civic EX now shifts quite smoothly, not harshly.

tony_2018

Ron drives auto? awesomeness.

Jimi Hondrix

Is it okay to mix those two brands? If so, I'm thinking I'll add Castrol a quart at a time over a few weeks or months and see if it helps smooth shifts.

CivicxTree754

Awesome read and great info. Sub

Former User

The whole point of drain-refill is to dilute the old ATF. One quart at a time defeats the purpose. Do full drain-refills.

tony_2018

No, you need to do a complete 3x3. Not a good idea to mix fluids but if you perform the 3x3 properly than most of the old fluid will get flushed out.

Jimi Hondrix

I just did the 3 x 3 using VML about 3,000 miles ago. Maybe I'll wait a while. It's only at lower speeds that it bothers me.

Former User

You created the thread apparently looking for potential solutions.

Do whatever you want.