81 SX4 Can Transmission Cause a Drain on Alternator

[Arctic_Eagle]

Have an 81 Sx4 automatic transmission. When in park and neutral the engine idles fine and all lights and electrical work fine too. When put into gear idle slows and headlights dim. Battery is 100%, replaced the alternator from a 40 amp to 63 amp and it is working correctly. When the car is in neutral the alternator is pushing about 14 volts, in gear and not moving it only pushes about 12. Sometimes the car stalls when I come to a stop other times not.

Can the transmission cause a drain on the alternator? I checked the fluid yesterday and its about 1/2 quart over full. Not ready to take the pan off to drain some out as it is about zero degrees here and I have no garage to work in. Any other Ideas what may be causing the drain?

[mudkicker715]

No to the tranny. Yes to an idle drop when in gear,which slows the rpm and thus slows the alt whichis your voltage drop. If every component is fine than your good.

[Arctic_Eagle]

Any ideas on the cause for the idle drop?

[thereverendbill]

Any ideas on the cause for the idle drop?

too much fluid in the trans like MK said

[Arctic_Eagle]

Sorry about that.  Miss read what he wrote. I'll drop the transmission pan tomorrow and drain some of the fluid off. Thanks.

[IowaEagle]

You may have to bump up your idle a bit.  Is the sole-vac working?

[Eagleearl]

It would be a lot easier to remove some oil from the transmission thru the oil dipstick tube with a cheap pump.
I pump mine out before dropping the oil pan to save on the mess.
May need to raise the idle speed in extreme cold.

[Arctic_Eagle]

Tried syphoning out the fluid and it was cold enough that the plastic tubing froze stiff.  Not sure why I didnt come up with increasing the idle...it's - 17 here today w/o windchill guess that qualifys as cold enough to bump the idle up. I'm sure the transmission fluid being over didn't help either though.

Car still started strong with no hesitation, so thats a good sign.

[mudkicker715]

Any ideas on the cause for the idle drop?

too much fluid in the trans like MK said

Never said that. I wouldn't worry about a little overfill either. I still believe you have no issue unless you sit idiling in gear for to long

[Arctic_Eagle]

You may have to bump up your idle a bit.  Is the sole-vac working?

Sole-Vac? Not sure how I can tell if its working. Still an amateur when it comes to this stuff. 

[Arctic_Eagle]

Agree with MK. I don't think that there is anything that I need to worry about in the immediate, but everything I'm reading about the sol-vac is making me think that I may need to adjust or at least test it. If anything this problem is just annoying.

Working on a little more diagnosis to provide you all:

Car idles fine when the choke is engaged but after the engine is warm the idle drops pretty low and the car stalls. When I initially tested the alternator I didnt think to let the engine warm and see how it was functioning in and out of gear. Was busy most of the weekend and didnt drive it too much. Now I know that when the engine is warm (and the choke is off) it idles low whether in or out of gear causing the draw on the alternator and  stalling when stopped. Sometimes though it will run fine and I have no problems. Can usually start it up after it stalls so its not a huge problem....Not a lot of traffic to worry about in ND. Need to get a tach so I can get the RPM readings. Is there another way to know if the sol-vac is working?

Thanks for your help so far

[ammachine390]

Sounds like you just need to adjust all of the idle speeds.

Is there another way to know if the sol-vac is working?

Turning on the rear defroster or the A/C should bump up the idle.  Also, the Air temp switch in the air cleaner will bump up the idle if the pins are jumped together. And if you turn the steering wheel all the way to one side, it should bump up idle. It is possible the sol-vac is stuck, mine was. I got it freed up with some WD-40 and now it works again.

[Arctic_Eagle]

Thanks, I will work the sol-vac since since WD40 is fast (and easy). Still pretty cold here and I dont have a tach so I might take it in to have the idle adjusted.  Car ran alright this morning idle slowed a little bit but not like it had been.

Could the timing be off as well?

[allend]

usually if it starts good it's not the timing, probliy just a low idle  adjust it and test the sol-vac (which mine don't have) and everything should be fine.