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  #1  
Old 02-02-2018, 11:07 PM
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Always upshifts at 1600 RPM, no kickdown, help pls

I just pulled my autotrans to replace the pump seal. Job went smoothly however now my car won't downshift, won't engage 1st gear, and always upshifts before 2000 RPM.The kickdown solenoid clicks audibly when I press the pedal switch. Fluid level is OK. Pressure cable seems OK, however adjustment has no effect. With vacuum pump disconnected it shifts exactly the same. I can hold 3rd or 2nd gear by moving the lever. Before I changed the pump seal it shifted normally. Any ideas what causes this behavior?

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  #2  
Old 02-02-2018, 11:07 PM
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This is a 1986 190D
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  #3  
Old 02-03-2018, 01:57 AM
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Are you sure the control pressure cable is hooked up inside the transmission?

Sixto
98 E320s sedan and wagon
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  #4  
Old 02-03-2018, 03:58 AM
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No I'm not certain, seems like it is not. When I pull it past the adjustment point it stops firmly like the cable is not completely broken. Is it straightforward to check it is connected inside? Do I need to remove the pan?
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  #5  
Old 02-03-2018, 04:12 AM
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When I pull the inner metal cable it still feels springy, not slack, like there is resistance back there. Thanks for your consideration. After spending a week under the car on jack stands I'm haunted to now have a worse problem.
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  #6  
Old 02-03-2018, 12:30 PM
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I don’t know about the 722.4. In the 722.3 you have to drop the pan and have skinny tools/fingers to get the cable hooked up, or drop the valve body(?). Did you undo it at the transmission end when you pulled the transmission? Could there be a misadjusted rod between the throttle cable and the bell crank that pulls the control pressure cable?

As a test, decouple the cable at the engine end, pull the hammer out as far as it’ll go and tie it that way. Does the car hold gears longer this way?

Sixto
98 E320s sedan and wagon
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  #7  
Old 02-03-2018, 12:38 PM
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Sixto thank you for your attention. Yes I disconnected the cable at the throttle before dropping the trans. This allowed the cable to slack inside the trans (whereas it normally is not). We tilted the trans sideways with the passenger side (cable side) higher when sliding the trans back onto the floor jack. I believe at this moment the hook fell out the nipple. I'm waiting on some parts so I'll post again once I'm done trying to reconnect it.
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  #8  
Old 02-03-2018, 12:41 PM
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To answer your other question, it shifts at 1600 RPM REGARDLESS of everything
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  #9  
Old 02-04-2018, 02:52 PM
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Darn it the Bowden cable is already connected. Now I'll try adjusting the vacuum modulator.
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  #10  
Old 02-05-2018, 01:12 PM
WTB: 94/95 E320 Wagon
 
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Vacuum is not your problem, that controls the soft / hard nature of the shift, not the shift point.
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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC
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  #11  
Old 02-05-2018, 01:29 PM
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I dropped the pan to verify the Bowden cable moves the plunger arm full travel (it did). What else to check?
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  #12  
Old 02-05-2018, 01:38 PM
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I connected the trans vacuum modulator directly to the vacuum pump and it shifts at 2800 RPM at WOT. Pump puts out 20 Hg at fast idle.
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  #13  
Old 02-05-2018, 01:40 PM
WTB: 94/95 E320 Wagon
 
Join Date: Oct 2007
Location: Charleston SC
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From the ATSG transmission overhaul manual, under the troubleshooting section:
Complaint: Upshifts in lower speed range of gears only.

Cause / remedy:
1. Check [Bowden] cable control for control pressure whether disengaged or torn and make accurate adjustments. [Max interpretation: make sure your Bowden cable is attached at both ends, is properly adjusted, and is not damaged or broken in any way. I've heard of this coming unhooked INSIDE somehow, and it is a real pain to get it hooked back up.]

2. Check full throttle stop. (Accelerate by means of accelerator lever and check whether throttle valve rest against full throttle stop, readjust, if required). [Max interpretation: check that the injection pump throttle linkage will move all the way to the throttle stop when the accelerator pedal is pushed to the floor. This is worth checking out!]

3. Check regulator pressure, if regulator pressure is too high, exchange centrifugal governor. [Max's interpretation: Excuse to buy some tools and check out the transmission operating pressures? Probably too much for average DIYer.]
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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC
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  #14  
Old 02-05-2018, 01:42 PM
WTB: 94/95 E320 Wagon
 
Join Date: Oct 2007
Location: Charleston SC
Posts: 2,687
Quote:
Originally Posted by rcshaw View Post
I connected the trans vacuum modulator directly to the vacuum pump and it shifts at 2800 RPM at WOT. Pump puts out 20 Hg at fast idle.
That is still too low.

I'm surprised at this result! Did you change anything else? If you restore the original vacuum line configuration, does the behavior go back to "only upshifts at 1600 RPM"?
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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC
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  #15  
Old 02-05-2018, 01:45 PM
WTB: 94/95 E320 Wagon
 
Join Date: Oct 2007
Location: Charleston SC
Posts: 2,687
Describe how you are adjusting the Bowden cable please.

The starting point for adjustment is to tighten the cable with the throttle at idle until it is just at or maybe a little tighter than slack, and then test drive and tighten or loosen around that point until you are happy with the partial throttle upshift points and downshift points.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC
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