Transmission hard shifting (bump) when cruising @ highway speeds

[burtman]

My daughter has a 2001 Outback/L.L. Bean; 3.0 Engine, 4EAT transmission.  At ~151K, I replaced Trans. Duty C Solenoid, seals, clutch plates, several drain/refills on the transmission fluid and the front and rear axle differentials.  Generally speaking, the OB transmission has performed well since. 

 Since the work above, there is a very noticeable hard “bump” (hard shift) coming from the transmission (or differential) whenever the accelerator is disengaged/reengaged while “cruising” at highway speeds (60MPH+).  I’m not certain if the “bump” existed before the transmission work, but my daughter thinks that it did not exist before.

• If accelerator is pressed ever-so-gently while cruising at highway speeds, the bump doesn’t occur.  In other words, it can be minimized/eliminated if a conscious effort is made to VERY gently press accelerator while cruising.
• “Bump” not noticeable at lower speeds when accelerating/decelerating in low-speed, stop-and-go traffic
• I checked the dropping resistor - OK.   

The condition may be just normal/natural of an aging Suby, but I wanted to check to see if anyone here might have some ideas/advice on what is happening, whether it is a real problem worth concern, and what might be done to fix it.

• Could the clutch plate replacement @ 151K be related?
• Maybe something associated with the accelerator feedback in the ECU and/or the TCU?
• Or is it common and nothing to really worry about?

 Thanks in advance for any thoughts or advice…

[1 Lucky Texan]

OK, most of the symptoms you mentioned match a well known issue with that generation. There can be a 'flare' when accelerating at highway (actually, fairly high speeds in my experience - 75+) speeds.

as a test, try a battery disconnect reset (write down your radio presets, disconnect the battery overnight, or, disconnect, step on the brake pedal, wait 10-15 minutes w'ever, reconnect. Do this just before a road trip, or other highway usage. If it helps the issue, it is typical for that generation. If not, you may have some other problem.

Years ago, I posted about this with my 03. It was already a known problem. The TC will unload, then there's a downshift flare before the lower gear engages, then BAM, it can be terrifying. Can't be good for the drivetrain either. After I learned about it, always did the reset before road trip. I dunno how often , or if ever, you will need to do it if you are always driving at extreme highway speeds.

 

you may of course have a different problem.

[el_freddo]

Check your engine and trans mounts. 

Cheers 

Bennie

[1 Lucky Texan]

any updates?