Help ! Sudden No Auto Gear Shift
10-29-2012, 05:25 PM
#196
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10-29-2012, 05:39 PM
#197
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Still impresses me as a linkage problem (presumable internal, as external linkage opperation has been confirmed). If it where me I'd drop the pan and have a look at the internal linkage and see if it moves corespondingly with the shifter.
10-29-2012, 06:04 PM
#199
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I would call,
Nationwide Auto Recycling, LLC
1410 Lunenburg Road (Rte 70)
Lancaster, MA 01523
Local: (978) 534-0477
Toll Free: 1-866-534-0477
They have a 1989 trans (no lsd) with 21k miles on it for $2495.92
Nationwide Auto Recycling, LLC
1410 Lunenburg Road (Rte 70)
Lancaster, MA 01523
Local: (978) 534-0477
Toll Free: 1-866-534-0477
They have a 1989 trans (no lsd) with 21k miles on it for $2495.92
10-29-2012, 07:03 PM
#200
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10-29-2012, 08:41 PM
#201
Nordschleife Master
Thread Starter
After reviewing the pdf's Jim had supplied, I too was thinking perhaps the range selector lever was not engaging the follower of the detent plate and hence its linkage. What I find perplexing today is that after I installed the new modulator and supplied vacuum to it via a new (but temporary) line, the wheels would turn in the wrong direction when in reverse and only when given throttle (the same as the situation when in drive). This, I think, would speak to the problem still being outside the the selector linkage.
Do we think it a valve body issue ?
10-29-2012, 08:59 PM
#202
Can you get your hands on some gauges? I'm thinking you're not getting enough pressure to engage the clutches. Bad pump or regulator? The valve body doesn't seem likely to have failed in a way that would give these symptoms.
10-29-2012, 09:28 PM
#203
Nordschleife Master
Thread Starter
How do I test pump and/or regulator ? Point me in the right direction and I will work it through.
10-29-2012, 10:34 PM
#204
Rennlist Member
I bought
Works great. I have to route the hose over the top of rear LCA link mount and the resonator heat shield to protect the hose but I can drive and hold the gauge in my hand to read pressure. It is tricky getting in and closing the door while holding the gauge and bringing it in through the driver side window.
Mike
Works great. I have to route the hose over the top of rear LCA link mount and the resonator heat shield to protect the hose but I can drive and hold the gauge in my hand to read pressure. It is tricky getting in and closing the door while holding the gauge and bringing it in through the driver side window.
Mike
10-29-2012, 11:49 PM
#205
Nordschleife Master
Thread Starter
My Modulating pressure (M) has been dealt with. The Operating pressure (A) will tell me if my regulator valve needs to be replaced -> am I correct in this ? I see various codes that correlate with Operating pressure values, but I don't know which correlates to the 928. These values are from the Mitchell 722 pdf. Also, how can I measure the Governor pressure (R) if I can't drive the vehicle in the condition it is in.
10-30-2012, 07:29 AM
#206
Rennlist Member
Have you actually measured the modulating pressure and set it with a gauge? The mod pressure setting automatically affects the actual operating pressure. Governor pressure is part of the operating pressure so if operating pressure isn't right, the governor pressure isn't right. If you don't get the modulating pressure set correctly to spec via a pressure gauge then all your other fluid pressures might be incorrect, hence no operation.
Mike
Mike
10-30-2012, 11:24 AM
#207
Nordschleife Master
Thread Starter
Have you actually measured the modulating pressure and set it with a gauge? The mod pressure setting automatically affects the actual operating pressure. Governor pressure is part of the operating pressure so if operating pressure isn't right, the governor pressure isn't right. If you don't get the modulating pressure set correctly to spec via a pressure gauge then all your other fluid pressures might be incorrect, hence no operation.
Mike
Mike
I only tested to see if it would hold vacuum, and that the vac lines to it were adequate. The procedure is to measure the vacuum at the modulator while car in motion. I unfortunately can not do that.
10-30-2012, 12:27 PM
#208
Rennlist Member
are we not talking of oil pressure? and the possibility of a non functioning pump?
learning so much I actually cracked the transmission section on the WSM........first time in over 11 years
learning so much I actually cracked the transmission section on the WSM........first time in over 11 years
10-30-2012, 12:37 PM
#209
Nordschleife Master
Thread Starter
You're lucky with that !
When I start her, it seems that the pump is functioning -> nice quick drop down to the 20'C mark. I'm wondering if some valve or regulator is not allowing various cluthches, or other mechanicals to function appropriately because they can't get a pressure head to operate (?). I wish I knew where to look and what to test for. In the two comprehensive 722 pdf's that I now have, there is a testing algorithm for various problems, but none are presenting like the ones that I have.
My dilemma came on suddenly and quietly as if it were an electrical issue, that is why I'm thinking pressure related failure. It is probably some small valve or regulator that failed (I think), thus it could be repairable.
10-30-2012, 12:44 PM
#210
Since you previously note you think there's good oil flow I'm thinking a blown seal, a busted line, or a bad regulator or governor. Unfortunately (well fortunate for me) I don't have any practical experience with these trannys. We'll have to wait for a pro to chime in. I think though if you hook up the gauges you will find very low pressure and that is enough for a start.