Car jerks when decelerating (<1000rpms)

My 2003 Acura MDX has been giving me issues whenever I am coming to a stop. The car will let out one big jerk when I am decelerating and hit just below 1000 RPMS. It does not shudder. Just one jolt that feels as though someone lightly rear ended me. I recently had the transmission serviced and had the fluid changed (not flushed). The car has 149,000 miles on it and had a transmission rebuild at 100,000 miles. The acceleration works fine and it does not give me issues when I switch gears. Anyone have any theories as to what the issue may be? I heard from a buddy of mine that my throttle body may be dirty but I’d like to get another opinion.

Torque converter unlocking harshly or improperly? My gut says look at driveline, particularly that transmission that you just flushed. FYI, almost no factory service manuals advise fluid exchanges on trans fluids. They recommend doing drain/refill or drop pan/change filter. There’s reasoning behind this.

Yes, it was a drain and refill. Not flushed

Thank you for your input. I will have my mechanic take a look.

Here’s to hoping for few $$!

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You may be right about the torque converter. I just ran a small test. I let the car warm up for about 4-5 minutes, then I revved the engine twice. Once it was back at idle I pressed on the brakes and slowly shifted to each gear.
P - none

R - none

N - none

D5 - big jerk

D4 - none

D3 - none

1<>2 - none

Every time I switched from N to D5 or visa versa, it jerked very hard. The shift from N to D5 felt comparable to when you stall out a manual transmission

I would imagine that that large bump would be regardless of which forward gear you put it in right after neutral. However, I know the selector lever only allows it to go into D5 after neutral. You could for kicks try quickly selecting D4 just to see what happens, I suspect same abruptness.

Stupid question…I assume you have checked the tranny fluid level?

Based on the stated symptoms, I think that there may be more than one problem.
The “jerk” when decelerating and getting down to ~1k RPMs is likely a very hard downshift to first gear, and it could be due to something as simple as a low level of fluid in the trans.

The large bump when first engaging the transmission is almost surely a different transmission-related issue.

I strongly recommend that the OP get her car to an honest trans shop a.s.a.p.

Transmission fluid is full and clean. I had a coworker who works on cars come out and look at it with me. Sure enough, it jerked and there was a loud ping sound when I went to D3 this time. He watched my engine as I switched gears and the engine was jumping around. He inspected it further and tested a few more things. He thinks one of the transmission mounts has broken. I knew they were worn from the last inspection I had but that was 2 months ago. He is going to jack it up at his place next week after the holiday weekend and give me an update. I’ll let you know what he finds.

Given the history of trans mount problems for Hondas and Acuras of that era, it is entirely possible that the trans mounts (and possibly motor mounts) need to be replaced.

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I took it to a trusted transmission shop 2 months ago. They offered to do a rebuild but said if I keep up with fluid changes the rebuild wouldn’t be necessary. They did tell me my mounts were pretty worn down. I have a coworker who does good mechanic work and when he looked at it he also believes one of the mounts is now shot. The engine jumps when I shift into drive.

Let us know if it fixes it!

UPDATE
The car is in the hands of my mechanic. He is having the transmission inspected. He drove it around and when he started it in D1 and manually shifted, all the gears changed just fine. On his way back to the shop, the engine light popped on and the car threw itself into neutral when he shifted into D3, D4 or D5. Reverse, D1 and D2 still drive fine. It’s looking pretty bad. I’m anticipating a rebuild but nothing is definite yet. He said it could be anything from a filter clog to a shift solenoid to a bad transmission. He doesn’t work on transmissions himself but he has a guy that is looking at it for him. I’ll keep you posted.

Let us know…knowledge is power!

Okay so I took it into the shop… the shift solenoid is shot. The linear solenoid was replaced in 2017 but Acura’s carry 2 shift solenoids and the other one has gone bad. I’m having it towed up to the shop that did the rebuild in 2017 bc it is still within the 36k mile warranty. Hopefully this is all we need! I’ll keep you guys posted after I get the solenoid replacement to let you know if it fixes the transmission problems

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