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I have a 1993 240 - with automatic transmission which was just re-built this week (according to the mechanics, the transmission was full of shavings and needed to be rebuilt - I might have been a sucker). Fuse #12 was already blown when the mechanics had the car -so they didn't hear this noise. They didn't have any of these fuses, but I did at home, so I replaced it when I got home. When fuse #12 is NOT in place, the transmission seems to shift without noise and seems smooth (but windows don't work and need to press Shift Unlock button to get out of park). When Fuse #12 is in place and connected, the windows work and shifter works w/o button needing to be pressed (reverse lights don't work though) - BUT I do have a horrible noise when shifting through the gears and from reverse back into Park it will grind and die. This also happened last week before the transmission was re-built (which made me think the mechanic was right and the transmission was jacked up). But now that it is still doing this when Fuse #12 is connected, it indicates the problem is something else - ANY IDEAS ON THIS??? My wife is not happy because I have sunk too much money into this car - please help me get this fixed so I can get out of the dog house.
Before all this really started, I had taken the car to a wash to try to get a bunch of oil off the undercarriage (had some bad gaskets I had replaced and it was a real mess underneath. I did spray in the engine compartment (not full force, except down lower by the transmission - lots of build up) Could I have sprayed something accidentally in the engine area that messed this up?
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Hello Robert,
Just to rule out the AC compressor, with fuse 12 inserted, disconnect the green bullet connector at the rear of the unit and see if your "grinding" continues.
Marty Wolfson
Proud member of the 300K club
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Is that just an electrical wire coming off this unit? I don't have the car right now, so I can't look at it, but Ill try that a soon as I can.
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Yup,
I think on the 93's it's a green wire that connects to a white wire which then proceeds into the bowels of the compressor. Disconnect by pressing the two wings and pulling.
Marty
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Thanks. The shop hasn't had enough time to go through it yet, but they did find that the shifter had a bunch of descintigrated parts in there (neutral safety thing and some severed wires), so they are replacing some of those to see what impact that has on everything. I did let them know that the bulk of the board here suspect the AC parts (compressor...) may be seizing and he said he would pass that along to the tech to check out as well.
The adventure continues...
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"so they are replacing some of those to see what impact that has on everything"
Sounds like my donkey-way of fixing things. I think they call it the shotgun approach. Other people call it luck. I'm rarely lucky and I don't think you will be too. Don't let them spend too much of your money monkeying around.
Sorry, for not being nice too.
Marty
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Mystery solved - there were broken up parts in the shifter that had to be replaced, the neutral safety switch was replaced and the inhibitor relay. I couldn't find any diagram that actually spoke of an Inhibitor relay, so I'm not sure which one that is. The shift was jacked up. When I would try to shift it, the handle would rise up to meet the button, instead of the button being pressed down. Now the shift is solid and the car runs like a champ! Plus I can operate the windows, which is good since the AC doesn't work.
Another positive thing, after the transmission work was done, I was told the button to disengage the 4th gear was not operational b/c of crap in the shift mechanism - and now that button works also.
Had nothing to do with the AC compressor or the starter.
So - their shotgun approach was spot on. I guess I got lucky this time.
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That doesn't explain what was grinding. I am pretty certain it was not the transmission. If you ever hear an automatic transmission grinding, it will be dead soon.
My guess is that the shift-lock solenoid had shorted out to the starting circuit, sending power to the starter solenoid. I cannot imagine how your shifter box became so mangled that that could happen, but it's the only explanation.
Glad you got it sorted out.
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I was mistaken about the transmission. I think it was the starter getting juice at the wrong time. But they have it all sorted out and the shift is nice and solid now and the car runs smooth.
Thanks again to everyone who chimed in to help me out.
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I'd be concerned about the transmission building up shavings again.
I'm not familiar with the workings of the shift unlock button but power may be going to the transmission when it shouldn't be. Find a way to disconnect the power to the tranny with fuse 12 in place.
The people who fixed your tranny may not be held liable if it's an electrical problem with the car and not the tranny.
--
1980 245 Canadian B21A with SU carb, M46 trans, 3:31 dif, in Brampton, Ont.
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There is not a single electrical connection to the AW70 on a '93 240 except for the overdrive solenoid.
The schematic I am looking at says the OD relay runs through fuse 11 (I couldn't remember if it was 11 or 12 last night) so I am assuming the fuse 12 thing was a miscount, because there is nothing electrical which could cause transmission problems except for the OD solenoid.
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"...There is not a single electrical connection to the AW70 on a '93 240 except for the overdrive solenoid...."
But is there not some sort of electrical limiting that prevents the OD from engaging when it's not in high gear forward "D"rive? For instance, you don't want the OD engaging when you're in reverse, or when you're accelerating up through the gears in Drive. Or is this all done through the hydraulic valving?
I gues I'm thinking that maybe something is shorting somewhere. What happens when the fuse is refreshed and the wire is disconnected from the OD solenoid?
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Nope. When you start the car, the OD solenoid is powered from the get-go, and the transmission's mechanical and hydraulic components control everything. It seems to be a commonly held belief that the ECU knows something about the transmission behind the engine, but it really doesn't have a clue, and cannot control anything to do with shifting. There is no electrical interaction with this transmission, except insofar as the OD solenoid passes ATF (or not).
As I said, I don't know enough about the transmission to visualize what could be causing the grinding, but if P1: it is in fact the transmission grinding, and P2: it is an electrical problem, then the OD solenoid is the source of the problem.
Verifying those premises would be the first order of business.
Better yet, here is my advice: Remove your glove box and find the OD relay just to the left of the opening. It will be clipped to the console support if it has never been moved. Pull the white relay out of the connector. Your OD should now be disabled. Put fuse #12 back in and go for a drive. If you do not hear the grinding, the OD unit in the transmission is the cause (Unless somebody has rewired the solenoid in the past).
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Yep - the overdrive is #11. I just replied to a post above with my testing results of removing #11 (while having #12 in place) and getting the arrow again, but the noise continues and it did grind and die again when going back to P. But when #11 is in place and #12 is removed, the car starts and idles smooth with no issues shifting (once the shift lock button is pressed).
Please read my other post for a more detailed explanation for my test and any further insight would be much appreciated!
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According to my Mitchell Schematics, fuse #12 powers these items:
Shift Lock Relay
Power Window Relay
Cruise Control Switch
AC Delay Relay
Window Defog Switch
Door and Seat belt warning Chime
What kind of noise are you hearing?
You say that the noise is horrible, any similiar noise that you can think of?
Where is it coming from?
Could the noise be a relay that is buzzing?
You say that the engine will die if you shift thru the gears?
Since the noise goes away when fuse #12 is removed, it doesn't sound to me like the noise is coming from inside the transmission.
steve
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The noise definitely sounds like gears grinding. With #12 in place, while staying in a parked position and shifting, there is definite noise and then it tends to die when I go to Park (I tested that again this morning, but I'm not doing that again).
When I got the car initially, the #11 was blown which is for the overdrive on/off engagement and the windows worked fine (so #12 was ok). So I tried pulling #11 and putting #12 back in place. The UP arrow light did appear as it did originally, but the noises were the same and it died going back to park.
I can tell the problem exists right away when I start it because the idle is rough and then when I bump the shifter just a bit, but keeping it in P, the noise goes away. When #12 is removed, the idle is smooth when it starts and there are no issues.
So it seems there is something with the electrical path that is connected to #12 that somehow partially engages the gears.
Could the overdrive solenoid be bad and I just need to get the bypass plate?
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Sorry about confusing the fuses last night, but the fact remains that the only thing electrical related to the transmission is the OD solenoid. The solenoid in the AW70 transmission does nothing but pass fluid, meaning if that is the cause of your grinding and transmission shavings, then a bypass plate will not help. If you recently had your transmission rebuilt - what did that involve? - and it is making noises, you need to immediately take it back to the shop that did the work.
Is there any possibility that this grinding is not coming from the transmission at all?
It may also be time to suspect prior "custom" electrical work, and check to see if your OD relay is behind fuse 11.
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I guess the noise could be something other than the transmission. Whatever it is, the sound is a grinding sound and the engine dies when going to Park. Could anything else cause this? When it dies, all the lights on the dash shine and then I have to wait a second with I try to start it again.
I'll get into the glove box and take out the relay to see what that does.
I want to thank everyone so much assisting me with this!
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Ok - making headway - I removed the OD relay and still had the problem, so it isn't transmission related. The sound when it is starting is a screech and it did almost die.
I had my son video the starting of both with and without #12 in place and he said there is no noise w/o the #12. He thought the screech came from the rear of the engine. He was pointing to the area where the dip stick is.
Since #12 is also AC related - (the AC doesn't really work), could there be something associated with one of it's components that could seize up and halt the engine? Possibly something that is related to when the gears shift from drive back to park?
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It sounds like something is going nutty with the starter. Like maybe it's engaging when it shouldn't.
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I just swung by an import shop and they are giving it a diagnostics look-over, but that was their first thought also. When the #12 fuse is in place, it trys to engage before it should. Electrical issues can be a bugger to figure out. Just hope they can actual diagnose the root issue and I can put this all behind me.
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The starter should have no relation to fuse 12. I'm betting on the A/C compressor. Easy to confirm.
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Sorry, late to the party, but yes. Me too. AC compressor. Easy to rule out.
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They have the car for now to do their diagnosis. Before I do anything they suggest, I'll remove the relay for the AC and see what happens.
Thanks again for the input! This is a good group of knowledgeable folks. It is much appreciated!
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You say the AC doesn't really work, that combined with the AC also being on fuse 12 makes me think something is amiss with you AC compressor, belt slipping or compressor about to or is seized.
Deloc
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I would look to the A/C next. I can't imagine what else could be related to fuse #12 that would screech. You could disconnect the A/C relay, which I believe is behind the passenger side kick panel, on the side of the center control console. It should be clipped to the upright support, and you can reach it by simply removing the side panel.
Take out that relay and see what happens with fuse 12 in. It could be something is wrong with the A/C relay or compressor clutch, or both.
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Could it be fan belts sipping or the harmonic balancer pieces slipping.
Does the noise go away once the engine is running?
Dan
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Also - when I initially got the car, the engine started fine, shifting was fine, it just didn't go into overdrive. I didn't have these noises - otherwise I would have passed on the car.
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Well, I don't understand the workings of the transmission enough to say why, but it sounds like the overdrive unit in the transmission might be trashed. The only thing on fuse 12 that could possibly affect the transmission would be the OD solenoid allowing the transmission to engage overdrive. To my knowledge.
I hope you have a warranty on that rebuilt transmission, because it sounds like they got it wrong.
Your water spraying did not cause this.
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