Bad news is that I keep finding things to fix

Based on my experiences, this never stops.

I think problem #1 and #2 are related, as they are both could be caused by vacuum leaks. Are you sure it is slipping and not just lagging with shifts?

As to fluid leaks - watch this video first:

 

Bad news is that I keep finding things to fix

This is true for any classic car. I have a pair of 54 Chevrolets for which I compile a annual maintenance list a for each spring aside from immediate needs. There is a point where you need to stop looking for problems.

Problem #2 My automatic locks are not working. I checked the yellow vacuum line near the firewall and it seems to be holding vacuum pressure going into the firewall. I can lock and unlock each door with the key, but the interior lock mechanism does not seem to work (or I am afraid I will break it with too much pressure). I am thinking that the actuator maybe bad, but I am looking for some guidance.

Problem #3 Cluster jumping - The oil pressure gauge and fuel gauge are jumpy. After repairing a bad fuel sender and connecting the oil pressure sensor cable properly, the gauges jump around when accelerating. I read about ground the cluster and tried, but it has not seemed to help. Maybe I did it wrong.

Problem 2 is vacuum related. On my 380 I started with the engine area and looked at all the vacuum connections. Word of advice. Follow the online maintenance manual vacuum diagrams. I found multiple mis-connected vacuum connections that were direct vacuum leaks but didn't look like it. Make sure you get the right diagram for the 83. Once I corrected my engine vacuum connections the central locking system started working again on its own. I used small pull-ties to serve as hose clamps to snug up the connections.

On problem 3, check to see if you have a ground wire from the chassis to the instrument panel. The lack of proper ground can cause jumpy gauges and other rather odd behavior. On mine when I flipped the turn signals the oxygen sensor light would flash. ?? Ya odd. I attached my ground wire to the drivers side top screw where one of the assembly screws threads into the clusters metal frame -- at the top of the speedo.

 

It took me a week to fill my transmission to the proper level. The marks on the dipstick are just a few mm apart. There is an overflow outlet, perhaps that is the source of your leak -- if it was down just enough to give you shifting problems, 7/8ths of a quart was a lot to add. Good luck!

 

I think you may be right. I think I overfilled it. I decided to pump out the existing fluid and it is filthy. If it were draining right out I would think that it would be empty and dry. I am hoping some fresh fluid at the right level resolves the slipping problem.

 

Well in that case drain the whole thing, put in a new filter and get some clean floyd in there.

 

+1 and drain the torque converter.

 

Problem 2

My door automatic locks never worked. And I always had to use a key to open the passenger door from the outside. When I replaced the interior I decided to fix all of it. First I started at the driver door. A vacuum hand pump is essential.

First thing I found is that the actuator in the drivers door was bad.
Once I replaced that, the passenger door would lock and the problem of having to open the passenger door with a key resolved itself but only when the car was running.

Pulled out the glove box, behind there is a Y connector that sends vacuum lines under the carpet to the gas flap and trunk actuators. I disconnected the lines that go back and plugged them with golf Tees. tried the doors again. this time the system held vacuum with the car on and off, so that told me my problem was at the gas flap or trunk actuator. replaced the Y connectors with new rubber ones. Went in the trunk and removed some carpet. plugged the trunk actuator and found one of the gas flap actuator hoses disconnected. connected it back up with new connecter rubber. now everything works....

Basically pull the door cars and the glovebox, grap your vacuum hand pump and start testing the circuit from the drivers door, around the car to the trunk. Its actually pretty simple. I also had a few actuator pods that where going bad. just test those with your pump as well. easy fix... Good luck!.

 

The good news is that I no longer think I have a transmission leak. I refilled the transmission to run some Seafoam through it. The transmission is shifting smoother than it was before, but the slipping is still there and happens pretty quickly. Many times the car will not even go into gear. I have ordered a new filter and pan gasket kit. I will drain and flush it next. Could a clogged filter result in the tranny not going into gear or failing to engage on shifting?

 

Keep going. Clearly it has not been serviced in a long time and I think it will settle down once it is in proper trim. If it persists you may have a 'piston problem' which others can elaborate, a known fault that can be resolved.

 

Badly Maintained Tranny...

UPDATE: I drained the torque converter and transmission pan as advised. At 2:00AM I decided to go to bed. I am about half way through putting the transmission pan and shroud back on, but when I pulled the pan off there was a good amount of debris in the fluid on the bottom of the pan. See attached. The fluid was not really burnt smelling, but it was dark, not pink or bright red. The filter was also pretty dirty. I forgot to take a picture of that. I did not find any metal parts in there, but plenty of clutch material. Do you think that clean fluid with some lucas (my plan tonight) will resolve my slipping problem, or based on the amount of clutch material in the fluid do you think I will need an overhaul/replacement tranny? I have had the car for 6 months. It has been slow going into gear the whole time, but it was not slipping until last week.

 

Maybe fixed?

I finished up reattaching the transmission drain pan and shroud last night. I filled the transmission with 1 quart of lucas and approximately 6.5 quarts of Castrol high mileage AFT. I was able to take a quick drive to fill up the tank and back home (5 miles or so). So far no slipping. I will need to take a longer drive to see if the fluid/filter change has solved the issue.

 

Tranny Issues again

I finished up reattaching the transmission drain pan and shroud last night. I filled the transmission with 1 quart of lucas and approximately 6.5 quarts of Castrol high mileage AFT. I was able to take a quick drive to fill up the tank and back home (5 miles or so). So far no slipping. I will need to take a longer drive to see if the fluid/filter change has solved the issue.

I am really enjoying spring temperatures for driving the SL. I noticed a couple weeks ago some flaring going from what I think is 2nd to 3rd gear. Today I went on an errand and got stuck in some gridlock (happens in Atlanta all the time); had a lot of starting and stopping. Towards the end of my drive, the car started slipping out of gear not only on the highway going 70+mph but also when I got onto surface streets when accelerating. It even stalled while coasting around 10 MPH. Once I started it back up, the slipping seemed to be gone, but the flaring continued.

I saw this post, but I'm having a hard time narrowing down what the issue might be.

The fluid level seems fine and the color seems ok still. It has less than 2K miles since the last fluid change. I recently adjusted the throttle linkage and bowden cable after replacing my injectors. I have not replaced the transmission modulator, but the vacuum line seems to still be connected.

Thoughts?

 

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^ As dirty as it was I just might have to do a filter and fluid again after a few miles were it mine...

 

Good point. I will pump some fluid out after about 40 miles and see how bad it looks.

 

I am hugely surprised fluid flush fixed it. Usually when automatic transmission slips, as opposed to hesitates with gear changes, shifts roughly, or refuses to go into gear, it is friction disks that are gone and new fluid won't bring it back.

 

So I think I have made some progress on the door locks. I was able to isolate the main leak in the line that runs from behind the glove compartment to the trunk (where it splits off for both the trunk lock and the gas tank lock. So I plugged that line and now my passenger door will unlock when the driver side door unlocks, but it will not lock fully when the driver side door locks. I have lubricated the locking mechanisms on both doors and they seem to move easier with the key now. I am wondering if I have a bad actuator in the passenger door, drivers door or both. How would I test this?

 

To test the door actuators simply apply vacuum at the connecting line and check if it holds vacuum. If the system works fine right after the engine runs, but not after sitting, the vacuum reservoir under the RHS front fender could be the culprit

 

I found the problem with the passenger side door lock. It was not vacuum related. The rod that lock and unlocks the door has some sort of wire that keeps the tension for the locks. That wire was broken on one side. After fashioning a new wire to hold the tension, the locks for at least the doors are working.

I would like to replace the line going to the trunk without taking too much of the car apart looking for it. Do you know how the yellow/red vacuum line runs after it leaves behind the glove compartment and heads to the trunk? Can it be accessed easily?

 

Vac line to trunk.

You should be able to see the vac line if you lift the carpet in the trunk.

 

thanks...I was able to track down the vac line and re-splice it.

 

I should have mentioned it's under the stainless steel trim under the door on the passenger side (USA) but you obviously found that.