Hesitant shift.
Thread Starter
Burning Brakes
Joined: Oct 2001
Posts: 1,185
Likes: 0
From: New Wilmington PA
Hesitant shift.
I've noticed a slight hesitation on the 1-2 shift of my TH-400. It might be there on the 2-3 shift too but I can't remember. (car is off the road for the moment.) It doesn't feel like it's slipping just hesitating.
What is happening: During normal driving everything seems fine. If I drop it into first and hammer it from a stop it waits about a second and a half after I bump the shifter to second before it does anything.
Any clues?
Transmission fluid is pink and doesn't have the distinctive burned smell.
Is this just normal operation?
What is happening: During normal driving everything seems fine. If I drop it into first and hammer it from a stop it waits about a second and a half after I bump the shifter to second before it does anything.
Any clues?
Transmission fluid is pink and doesn't have the distinctive burned smell.
Is this just normal operation?
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: Hesitant shift. (Cookwithvette)
That is what is called wide open throttle upshift and if the electric kickdown solenoid is functioning it will shift very late. If you r engine is not in PERFECT tune it will feel almost like the trans is not going to shift. Just back off the gas slightly so that the electric solenod is not engaged and it will shift right on. One of the quirks of the TH400.
[Modified by silvervetteman, 4:56 PM 9/3/2002]
[Modified by silvervetteman, 4:56 PM 9/3/2002]
Thread Starter
Burning Brakes
Joined: Oct 2001
Posts: 1,185
Likes: 0
From: New Wilmington PA
Re: Hesitant shift. (silvervetteman)
Hmm... interesting.
I did forget to mention one thing though. :bb The mechanic who finished my engine install found that my detent switch wire(s) had been tied off and stuffed aside, not connected to anything.
Could this be related to the vacuum modulator?
What's troubling is that if I don't put the shifter in 1st the transmission will shift low at WOT. :crazy:
I did forget to mention one thing though. :bb The mechanic who finished my engine install found that my detent switch wire(s) had been tied off and stuffed aside, not connected to anything.
Could this be related to the vacuum modulator?
What's troubling is that if I don't put the shifter in 1st the transmission will shift low at WOT. :crazy:
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: Hesitant shift. (Cookwithvette)
The modulator controls shift points and firmness. Sort of a co-ordinated shift. I don't think the modulator can cause a no shift. A stuck detent valve can though. I think you should very precisely adjust the shift linkage and check for vacuum leaks and fix the detent solenoid. You need to start with everything working correctly and go from there. ANY fluid in the modulator line (even one drop) require replacement of the modulator.
Thread Starter
Burning Brakes
Joined: Oct 2001
Posts: 1,185
Likes: 0
From: New Wilmington PA
Re: Hesitant shift. (silvervetteman)
Good point. I'll try connecting the detent switch and check out the modulator. Don't seem to have any vacuum leaks. Just finished playing "whack-a-mole" with them in June and believe I got them all. :)
Thank you very much for your advice.
Thank you very much for your advice.
