My 89 Bonney is shifting unreliably. It takes a few blocks before it will shift normally. Once it shifts the first time, it's ok unless I shut the car off for like 12 hours.
Recently though it started banging while it was shifting up, down and reverse. But only when it feels like it. It shifts fine . . . I'll go into a store, come out and start it up and it starts banging. The last time it did this, I got the idea that maybe some universal force is at work here, and it didn't like the way I started the car. So I turned the car back off, turned it back on . . . . and appeased the automatic transmission gods somehow, it shifted fine again. So I figured I need to get up to speed (sorry) on automatic transmission workings 101. I've bought a new modulator for the paltry cost of $17.99. It's a 5 minute fix, but I kinda want to know what it does.
2007-01-19 08:31:27 · 8 answers · asked by ExcelerNot 2 in Cars & Transportation ➔ Maintenance & Repairs
Interesting answers so far but:
1) It's an 89, I really don't care if I look in the mirror and see my tranny skidding on the pavement, I'm not spending $1400 to rebuild the tranny, (which is the only thing a shop is gonna do). I can buy a whole new beater for that!
2) This same thing happend 2 years ago, and I did bring it to Safeguard transmission, they charged me $200 to change the fluid and (drumroll please) CHANGED THE MODULATOR. Hmmmmm the "Experts" changed the modulator . . . for $200 . . . I want to do it fer $20 and that's a bad idea? The goopy fluid thing sounds possible, cause the problem got gradually better after a fluid change. I know there's possibly something else wrong, (and I _WILL_ check the vacuum lines, that's reasonable), but WHY does restarting the car make it go away?
Doo doo doo doo, doo doo doo, doo doo doo doo, doo, doodoodoodoo (theme from Jeapory)
2007-01-22 03:34:21 · update #1
Errrrr, I mean Jeapordy, yeah, that's it.
2007-01-22 03:40:35 · update #2
You have leaking seals in the trans clutch packs - over the years they tend to get hard especially cold. The best bet is overhaul but since apparently you have nothing to lose, try some additive that may restore some of the o'ring rubber qualities.
2007-01-25 05:21:52 · answer #1 · answered by Anonymous · 0⤊ 0⤋
A bad vacuum modulator would make the transmission shift sooner or later than normal. Your problem is something else. Most people try a full flush just in case it's old goopy fluid causing the problem. If that doesn't work, it's a trip to the shop.
2007-01-19 17:11:49 · answer #2 · answered by Nomadd 7 · 0⤊ 0⤋
The vacuum modulator "tells" the transmission what the engine load is. For example, at wide open throttle and low speed, vacuum would be very low so the transmission (in combination with the governor) makes a decission to shift down. It just transform manifold pressure into a specific position for one of the valves in the transmission's valve body (which is the brain of the transmission)
2007-01-19 16:37:36 · answer #3 · answered by Anonymous · 0⤊ 0⤋
The symptoms you describe would have nothing to do with the vacuum modulator. All that does is look at vacuum to see how far you have your foot into it, and change the shift points accordingly.
Instead of buying and replacing parts, take it in to a good transmission mechanic, and get it fixed before you have a tow bill too. It's giving you plenty of warning. Do it. Do it now.
2007-01-19 16:39:36 · answer #4 · answered by oklatom 7 · 0⤊ 0⤋
Shifts the auto trans by regulating the fluid flow inside the trans. Make sure all vacuum lines are in good condition and tight.
2007-01-19 16:38:17 · answer #5 · answered by Tinman_2_54 2 · 0⤊ 0⤋
Sonora M .,gave You, the right answer.
I only gonna add this....
replace the vaccum modulator a.s.a.p. or something gonna brakes badly.
2007-01-19 17:09:22 · answer #6 · answered by Anonymous · 0⤊ 0⤋
it helps transmission shift right
2007-01-27 14:44:01 · answer #7 · answered by ? 3 · 0⤊ 0⤋
I think it is in the glovebox
2007-01-19 16:34:12 · answer #8 · answered by Anonymous · 0⤊ 2⤋