I own a 1990 Chevy Lumina Van. She's still in pretty good shape but when I'm deccelerating there's a substantial "THUMP" when the automatic transmission drops from 2nd gear into 1st. Anyone know what that could be?
2006-08-14 11:31:26 · 9 answers · asked by ? 1 in Cars & Transportation ➔ Maintenance & Repairs
A few more details would help...ie...3 or 4 speed
The 3 speeds were know for a downshift clunk caused by a broken spring on the servo. This can be fixed without removing the trans. because the servo can be acessed thru the bottom pan.
One common problem with a downshift cluck in the 4 speeds was caused by a broken/leaking vac. hose for the modulator.
Broken trans. mounts will more likly cause problems on accel. because of the load .
Both are easy remidies for this type of concern....HTH
2006-08-15 04:15:30 · answer #1 · answered by trannyman166 3 · 0⤊ 0⤋
It COULD be evil spirits.
I don't think you're dropping from 2nd to 1st. I suspect your torque converter lock is thumping. Check your fluid.
The other possibility is you've got worn motor mounts. That "THUMP" you hear is the whole powertrain bottoming out. Try rocking the engine by hand (not running of course). If you can pull it forward and get a similar sound, you've solved your mystery!
2006-08-14 18:39:55 · answer #2 · answered by Wicked Mickey 4 · 0⤊ 0⤋
The pressures inside your trans are to high is 1st and 2nd
this could be caused buy a defective sensor or computer
or it could be some thing worst. Have a diagnostic done by your dealer or a well know trans shop. They sould only charge
you about $60.00 to tesll you whats wrong>
good luck
2006-08-14 18:43:20 · answer #3 · answered by james r 2 · 0⤊ 0⤋
Sounds like a sticky valve or a band problem. It's got a 125C so you can replace it with a used one from any junk yard. But before that, check the adjustment of the PTV cable. That would be a quick easy fix if it's just out of adjustment. Good luck.
2006-08-14 18:38:43 · answer #4 · answered by jeff s 5 · 0⤊ 0⤋
Normally, your transmission should never do that particular shift, at least not on its own. The only time it should go into first is at a standstill. Does it seem to thump in every downshift?
2006-08-14 18:36:59 · answer #5 · answered by InjunRAIV 6 · 0⤊ 0⤋
I'm thinking this maybe due to a bad engine mount. When the engines torques forward or backwards it slips againts the mount thus the thud. This is definately true if you notice it while starting off or goign in reverse.
2006-08-14 18:37:49 · answer #6 · answered by Briggs 3 · 0⤊ 0⤋
3-speed or Overdrive?
Specifics
Which transaxle. They have different quirks.
How about some guesses !
2006-08-14 18:41:54 · answer #7 · answered by Arnon 6 · 0⤊ 0⤋
could be a trans mount
2006-08-14 18:45:27 · answer #8 · answered by racingirlsmokesem 2 · 0⤊ 0⤋
ready to go.
2006-08-14 18:37:15 · answer #9 · answered by Anonymous · 0⤊ 0⤋