YACT: What would cause an automatic transmission of a car to jerk when shifting gears?

Arkitech

Diamond Member
Apr 13, 2000
8,356
3
76
Lately I've noticed that sometimes my car (Dodge Intrepid) jerks a bit when I change from reverse to drive. Any idea of what this means? Does my transmission just need maintenance or trans fluid? Or is it something worse?

Also what does it mean if you hear a grinding noise when shifting gears? (This has'nt happened to me yet but I've heard other cars with that problem)
 

MaxFusion16

Golden Member
Dec 21, 2001
1,512
1
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i'm no mechanic, but the samething happened to my dad's taurus, the car would jerk with a thump, 2 years later, the car's tranny blew on the road.
So i'd say get it checked out ASAP.
 

BW86

Lifer
Jul 20, 2004
13,115
29
91
happened to me, i felt a big jerk everytimg i shifted and i heard grinding gears. i drained the fliud out of my tranny and to my suprise it was running very low. I bought some new fluid pumped it in and it was gone. :p
 

T2T III

Lifer
Oct 9, 1999
12,899
1
0
If there's a big jerk, does it happen when the car is cold? Does it happen when the RPMs are high just after starting the car? If so, let the car idle for a minute to get the RPMs down to a normal range (700 RPM) and see if it minimizes the jerking.

Also, proper maintenance is required. Check your owner's manual to determine the intervals for transmission fluid changes. In my opinion, just dropping the pan and changing the filter are not enough - because only about 4 quarts get drained and 7 or so quarts remain in the tranny. My favorite is the BG Products transmission flush where essentially all of the fluid is replaced. I noticed some hard shifting on my vehicle and had this process done about 3 months ago. The tranny now performs beautifully. I opted for the synthetic fluid to be installed in my tranny and the service ran about $190 - including the fluid. I will now have this process done every 30,000 miles - even though my owner's manual indicates that I can go a longer span of time. However, I also live in an area where there is a log of stop-n-go traffic, so the intervals in the owner's manual can't completely be followed.

 

Arkitech

Diamond Member
Apr 13, 2000
8,356
3
76
THanks for the suggestions, this weekend I'll definitely need to take care of this.


Cars a such a scam, the automobile industry has been around decades. You would think by now they could put out more reliable products.
 

Gibson486

Lifer
Aug 9, 2000
18,378
1
0
Dude, your tranny might blow soon. Same thing happened to my mom's caravan. If you start having trouble pushing the gas down, do not take yoru car on the road because your tranny is about to go kapput and youe will see trail of tranny fluid from point A to Point B.
 

Oger

Senior member
Sep 30, 2004
438
0
0
Arkitech ;

Before you do anything else, check the tranny fluid first, to do this, drive the vehicle until it is fully warmed up, park the vehicle on a level surface, shift through all the ranges twice (that's park,neutral,drive,low2,low1), leave the engine running, pop the hood, remove the tranny dipstick, wipe clean, reinsert and then check the level.

THE LEVEL MUST BE AT "FULL HOT"

Second, with the key removed from the ignition, disconnect the negative battery terminal, reconnect it after twenty minutes.
Start the vehicle and drive it normally until fully warmed up, this procedure will erase the P.C.M. (power train control module) and allow it to "relearn" the trannies shifting characteristics.
These Chrysler trannies are well known for there shifting problems because they are entirely controlled by the P.C.M. and the Dodge/Chrysler engineers did not take into account the varying line pressures as the trannies gain mileage over time.


 

NutBucket

Lifer
Aug 30, 2000
27,034
546
126
Heh, why am I not surpised its a Chrysler product:p My friend's family has had nothing but trouble with their Intrepid's tranny.
 

DAGTA

Diamond Member
Oct 9, 1999
8,175
1
0
About the PCM, I have a question that is somewhat related and I'd apprecaite any advice/info you can offer. I have a 2002 Grand Am automatic. It doesn't jerk when shifting. The problem I'm noticing is that it will suddenly shift when I'm doing between 65 and 75mph for no reason that I can find. I'll just be driving along and I'll feel a slight shift and the RPMs jump up about 500 more then it gradually works back down. Any ideas of what could cause this?

Thanks for the help and I hope I'm not hijacking your thread, Arkitech.

-DAGTA


Originally posted by: synchronizer
Arkitech ;

Before you do anything else, check the tranny fluid first, to do this, drive the vehicle until it is fully warmed up, park the vehicle on a level surface, shift through all the ranges twice (that's park,neutral,drive,low2,low1), leave the engine running, pop the hood, remove the tranny dipstick, wipe clean, reinsert and then check the level.

THE LEVEL MUST BE AT "FULL HOT"

Second, with the key removed from the ignition, disconnect the negative battery terminal, reconnect it after twenty minutes.
Start the vehicle and drive it normally until fully warmed up, this procedure will erase the P.C.M. (power train control module) and allow it to "relearn" the trannies shifting characteristics.
These Chrysler trannies are well known for there shifting problems because they are entirely controlled by the P.C.M. and the Dodge/Chrysler engineers did not take into account the varying line pressures as the trannies gain mileage over time.

 

Oger

Senior member
Sep 30, 2004
438
0
0
DAGTA ;

That is the lock up torque convertor disengaging, not the tranny downshifting, follow the advice above, if it continues after doing so, P.M. me and I will guide you through a quick diagnostic procedure.
 

DAGTA

Diamond Member
Oct 9, 1999
8,175
1
0
Originally posted by: synchronizer
DAGTA ;

That is the lock up torque convertor disengaging, not the tranny downshifting, follow the advice above, if it continues after doing so, P.M. me and I will guide you through a quick diagnostic procedure.

Thank you. I very much appreciate it. I'll try resetting the PCM this weekend and see how it drives afterwards.

-DAGTA
 

Oger

Senior member
Sep 30, 2004
438
0
0
Please people, make absolutely damn sure the keys are not in the ignition when removing or installing the negative battery cable, I have a 55 gallon drum full of wasted E.CM,s and P.C.M,s out back, disconnecting or reconnecting the battery terminals with the key in the "on" position will destroy either the E.C.M.,P.C.M. or both.

Anytime DAGTA ;)
 

Oger

Senior member
Sep 30, 2004
438
0
0
virtueixi is absolutley correct, I forgot to mention that, using any other type of tranny fluid will destroy your tranny.

That's Chrysler atf 4.