Check resistance of a one-pin connector?
07-01-2011, 02:43 AM
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Re: Check resistance of a one-pin connector?
I'm no electrical engineer...
Transmission has an electrical component on it (kickdown solenoid). This solenoid only has a single wire going to it. I guess the ground is the component to transmission contact? Do I just put one lead on the wire and one on the chassis?
Transmission has an electrical component on it (kickdown solenoid). This solenoid only has a single wire going to it. I guess the ground is the component to transmission contact? Do I just put one lead on the wire and one on the chassis?
07-01-2011, 03:39 AM
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Re: Check resistance of a one-pin connector?
the ground would be contact between the sensor and the transmission. measure using the ground to both a clear spot on the tranny and on the exterior of the sensor.
07-03-2011, 03:30 AM
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Re: Check resistance of a one-pin connector?
Ok, well that wasn't the problem.
As long as Fabrik8 is in the room....
Trans works fine.
Park car last Sunday.
Come back to car and suddenly shifts are harsh and late.
Every now and then when I go to park the car it will be hard to put into R (to ultimately put in P) - it feels like it's caught on something but if I wiggle it and force it, it will eventually get into R.
Even after playing with the adjustments to get the shifts to be neither harsh nor late (as a band-aid because it's my only car and I needed to drive it), the full throttle with kickdown applied shifts are still late. Late as in the 2-3 shift will never happen, just bang off the rev limiter. And if you try to floor it at a speed too high for 2nd, it will still drop into 2nd).
I'm thinking I'm just going to need a new trans valve body, but if Fabrik8 has any thoughts....
Especially on why the the shifter gets caught up. That part confuses me most because it's a pretty simple linkage, and there's nothing external for it to get caught on. All I can think of is something in the valve body broke and made it's way to the internal part of the linkage. The clearance of the linkage is fixed by a solid piece of plastic, so it's not like it can get out of adjustment. I suppose it can crack though, but it seems like too much coincidence for that to have a problem as the same time as the rest of the trans.
If it helps, this is the same trans that is in a Porsche 928 (figure that will be more relatable than old Mercedes).
As long as Fabrik8 is in the room....
Trans works fine.
Park car last Sunday.
Come back to car and suddenly shifts are harsh and late.
Every now and then when I go to park the car it will be hard to put into R (to ultimately put in P) - it feels like it's caught on something but if I wiggle it and force it, it will eventually get into R.
Even after playing with the adjustments to get the shifts to be neither harsh nor late (as a band-aid because it's my only car and I needed to drive it), the full throttle with kickdown applied shifts are still late. Late as in the 2-3 shift will never happen, just bang off the rev limiter. And if you try to floor it at a speed too high for 2nd, it will still drop into 2nd).
I'm thinking I'm just going to need a new trans valve body, but if Fabrik8 has any thoughts....
Especially on why the the shifter gets caught up. That part confuses me most because it's a pretty simple linkage, and there's nothing external for it to get caught on. All I can think of is something in the valve body broke and made it's way to the internal part of the linkage. The clearance of the linkage is fixed by a solid piece of plastic, so it's not like it can get out of adjustment. I suppose it can crack though, but it seems like too much coincidence for that to have a problem as the same time as the rest of the trans.
If it helps, this is the same trans that is in a Porsche 928 (figure that will be more relatable than old Mercedes).
Last edited by marlinspike; 07-03-2011 at 04:33 AM.
07-03-2011, 08:36 AM
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Re: Check resistance of a one-pin connector?
I've got nothing, I'm not really knowledgeable with automatic trans troubleshooting though. 
I would suspect the valve body though, because with a fully functioning valve body (and control electronics) the trans should shift properly once the linkage is in the correct position. I'm not sure if the binding linkage is related or is a separate problem.. It's probably possible that the linkage (or whatever the linkage is attached to) is the problem, and the valve body is just mirroring the problems that the linkage is creating. The linkage should really only cause problems if the lockouts are mechanical instead of being controlled by a TCM.
Have you been making any vacuum modulator adjustments?
Looking around, it looks like the valve body is a big source of problems on the older Merc transmissions like you have.
I would suspect the valve body though, because with a fully functioning valve body (and control electronics) the trans should shift properly once the linkage is in the correct position. I'm not sure if the binding linkage is related or is a separate problem.. It's probably possible that the linkage (or whatever the linkage is attached to) is the problem, and the valve body is just mirroring the problems that the linkage is creating. The linkage should really only cause problems if the lockouts are mechanical instead of being controlled by a TCM.
Have you been making any vacuum modulator adjustments?
Looking around, it looks like the valve body is a big source of problems on the older Merc transmissions like you have.
Last edited by Fabrik8; 07-03-2011 at 09:02 AM.
07-03-2011, 10:16 AM
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Re: Check resistance of a one-pin connector?
TCM? TCM? We don't need no TCM (it's mechanical).
And I have been making vac modulator adjustments, but only after the problem started to get rid of some of the newfound harshness.
Though, I previously did have the vac modulator to full firm so that the car would bang through the gears. Maybe that killed it.
And I have been making vac modulator adjustments, but only after the problem started to get rid of some of the newfound harshness.
Though, I previously did have the vac modulator to full firm so that the car would bang through the gears. Maybe that killed it.
07-09-2011, 08:31 PM
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Re: Check resistance of a one-pin connector?
Well, in case those who responded are curious, I'm pretty sure finding most of a clutch in my transmission pan is probably a pretty good sign of what is wrong....