I've had a 99 EX auto with about 100k on the clock for a couple of weeks now. The previous owner put a cold air intake on it which I just left on it, although I do have the stock parts. My problem is this: the trans seems to shift rather late. Even at part throttle on flat roads it seems to rev up into the 3000+ range before it does shift. As a matter of fact, sometimes it will be hanging in third gear (have it in D4) and I'll pop it out into neutral, then back into drive. It will come back into thrid, then quickly into fourth (like it just realized it should have been in fourth to start with). I wonder if the CAI has an affect on automatic transmission operation due to the way it must affect the MAF sensor or some such thing? I changed the transmission fluid and the nothing changed.

At higher throttle the car seems to operate just fine, shifts quickly and appropriately.

I guess I just figured that the CAI must make the overall pressure in that system lower, and thus make the motor think the load on the engine is higher than it actually is.

Last little tidbit, if somebody knows: does a CAI increase or decrease gas mileage? I've heard both stories...

Thanks-

K

 

im not sure about that cai, but you can try changing the trans fluid and see if it shifts better

 

I think the '99 still has a mechanical controlled transmission. In that case, check the cable from the throttle to the transmission. It tells the transmission to let the engine rev higher (shift later) when you have the throttle wide open. If it's stuck that way you will get what you're getting.

I agree on changing the ATF is a good idea anytime you buy a used car. You don't know how many miles are on the old stuff. Get it from the Honda dealer, don't use generic ATF.

 

mk, it looks like 96-00 Civic ATs receive the throttle position information electronically (see diagram). Does this mean that gear shifting cannot be adjusted? Might the problem instead be with the throttle cable or throttle body?

Is the CEL ON or the D4 indicator light on the dash blinking? You might want to check whether a CEL code for the transmission is being thrown. Try pulling codes from the ECU as detailed at the link in my signature.

 

Would you categorize the problem as erratic shifting or flaring (see charts below)?

 

My 2000 EX shifts between 3000-4000RPMs. I have owned it since 76k miles and it has 91k now. I changed the fluid when I replaced the RH half shaft at 81k. I talked to a Honda dealer tech and he said thats normal for the higher revving before shifts. The tranny shifts just fine, I just thought it would shift at a lower RPM then 3000-4000. My GM cars all shift at 2000RPM.

 

Well I read some of the definitions in the notes sheet posted above. It posts different reasons for problems with 1-2 upshift and 2-3 etc. I think it would be pretty weird for both of those things to fail at once (shift solonoids). It also mentions the speed sensor as a problem, but I haven't seen any evidence of that with the speedometer or error codes.

I wouldn't describe the shifting as "erratic." Its simply very reliably and predictably late. I'm unclear as to what "flaring" is. It does rev higher than it needs to before shifting. I don't know if its harmful but I disagree with the dealership diagnosis above- it is clearly not normal.

K

 

Flaring is an abnormal increase (flare) in engine rpm (500-1000 rpm) that occurs between gear shifts for an AT. This terms seems to typically apply to transmission slipping, so I don't know whether it applies to your situation.

Is the throttle body or throttle cable possibly sticking?

 

Someone I know had the same problem with his prelude, it turned out to be he had a transmission fluid leak.

 

found a TSB, thought you might be interested for future reference. I'm thinking I have a problem with the linear shift solenoid. Looks like it is a culprit for 1-2, 2-3 and 3-4 shift issues. There is also a tech service bulletin out for it, posted below:

Here is the tsb for those codes.

00-012

June 26, 2001
Applies To:
1996-00 Civic - See VEHICLES AFFECTED
1997-99 CR-V - See VEHICLES AFFECTED

Harsh Shifting Automatic Transmission
(Supersedes 00-012, dated June 20, 2000)

Updated information is shown by asterisks and black bars.

SYMPTOM

*The transmission shifts harshly, or it may stay in first gear. The harsh shifting is more noticeable on the 1-2 and 2-3 upshifts under light throttle. It is not affected by operating temperature. The MIL may be on with DTC P0730 or P0715 stored.*

PROBABLE CAUSE

*Contamination of the linear solenoid and its associated passages inside the transmission, or a broken spring internal to the transmission.*

VEHICLES AFFECTED

CORRECTIVE ACTION

*Flush the transmission with Genuine Honda ATF-Z1, then replace the linear solenoid. If shift feel is not affected, replace the transmission.*

PARTS INFORMATION

Linear Solenoid Assembly: P/N 28250-P4R-315, H/C 5317219

Drain Bolt Washer: P/N 90471-PX4-000, H/C 3300936

REQUIRED MATERIALS

Genuine Honda ATF-Z1: P/N 08200-9001, H/C 6512628

Civic and 2WD CR-V - 11.6 quarts required
4WD CR-V - 12.4 quarts required

WARRANTY CLAIM INFORMATION

In warranty:
The normal warranty applies.

Out of warranty:
Any repair performed after warranty expiration may be eligible for goodwill consideration by the District Service Manager or your Zone Office. You must request consideration, and get a decision, before starting work.

REPAIR PROCEDURE

1. Raise the vehicle on a hoist.

2. Drain the transmission. Refill it with Genuine Honda ATF-Z1.

3. Start the engine.

4. With your foot on the brake pedal, shift the transmission to D4

5. Release the brake pedal. Press on the accelerator, and bring the speedometer up to 50 mph. Make sure the transmission shifts through the first three lower gears and into fourth, and that the torque converter locks up.

6. Apply the brakes to stop the front wheels.

7. Shift to reverse, and then to neutral.

8. Repeat the shifting procedure (steps 4 through 7) four more times.

9. Turn off the engine.

10. Repeat the above drain, refill, and shifting procedure (steps 2 through 9) two more times.

11. Drain the transmission. Reinstall the drain bolt with a new washer. Refill the transmission with Genuine Honda ATF-Z1.

12. Disconnect the linear solenoid electrical connector. Remove the mounting bolts, then remove the linear solenoid.

13.Inspect the linear solenoid mounting surface on the transmission. Remove any contamination.

14. Install the new linear solenoid. Reconnect the electrical connector.

15.Use the PGM Tester to erase any DTCs in the powertrain control module (PCM).

16. Test-drive the vehicle to check the shift feel. If it still shifts harshly, install a remanufactured transmission.*