Gold 1978 Trans Am - Newbie Questions

[Brosain]

Hello All!

I'm a proud new owner of a Gold '78 (non-Y-88) with a 400, auto, Hurst t-tops. I have a few questions that I've mustered up looking over this thing:

1. Looking to change the differential fluid soon. I'm used to seeing a plug on the diff cover that you unscrew or, in the case of my '86 Ramcharger, pop off a rubber plug to fill with fluid, then when it runs out, you're done. I don't see a fill screw on my cover. Is the fill location on the back of the diff somewhere, and if so, do you fill it until it starts to come out to get the proper level?

2. I can take the car out of the park and into any gear with it shut off, and they key out. I'm also able to start the car in "drive." Is there a neutral safety switch that needs replacing? If so, where would it be?

3. I have no reverse lights. My turn signals work, and the fuse is good. I switched out the bulbs for new ones and tested for voltage at the plug, but there is none. Any suggestions?

4. I only have three fan speeds, "hi" doesn't work. Blower resistor?

I appreciate any help you can provide.

 

[Hesster]

For Q1 - the STOCK Differential only has a fill plug, on the top RH side facing the Pinion. Square drive, use the end of a 3/8" extension. I suggest remove the 10 bolts off the cover, and remove it to drain the fluid.

differential cover 10 bolt - JEGS High Performance

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Drain out the stinky old fluid, and wipe out the crud when you are in there. Wear gloves as the old fluid stinks worse than a Skunk. Buy 2-3 Quarts Diff Fluid and ALSO the additive. This link will give you a idea of what is needed, or get it all from your local Auto store.

Loading Products... | Speedway Motors, The Racing and Rodding Specialists

www.speedwaymotors.com

Clean the cover, apply a thin bead both sides of the gasket, and reassemble. Do not over torque the bolts, ~20 -30 ft lbs max in a cross pattern.
Fill using one bottle, put in additive, then fill until oil just pukes out the hole. Thread the plug back in, use a little pipe thread tape on the plugs threads.

Q2 and Q3 - that is dangerous. Fix it - reference this -

neutral safety wiring on a 79 t/a

neutral safety wiring on a 79 t/a

www.78ta.com

Q4 - could be a resistor. Maybe check it with a OHM meter.

Blower motor stopped working

Blower motor stopped working

www.78ta.com

 

[79TURBO]

Hello All!

I'm a proud new owner of a Gold '78 (non-Y-88) with a 400, auto, Hurst t-tops. I have a few questions that I've mustered up looking over this thing:

1. Looking to change the differential fluid soon. I'm used to seeing a plug on the diff cover that you unscrew or, in the case of my '86 Ramcharger, pop off a rubber plug to fill with fluid, then when it runs out, you're done. I don't see a fill screw on my cover. Is the fill location on the back of the diff somewhere, and if so, do you fill it until it starts to come out to get the proper level?

2. I can take the car out of the park and into any gear with it shut off, and they key out. I'm also able to start the car in "drive." Is there a neutral safety switch that needs replacing? If so, where would it be?

3. I have no reverse lights. My turn signals work, and the fuse is good. I switched out the bulbs for new ones and tested for voltage at the plug, but there is none. Any suggestions?

4. I only have three fan speeds, "hi" doesn't work. Blower resistor?

I appreciate any help you can provide.

#3, Do you have headers?

 

[Brosain]

#3. Do you have headers?

I think so (?)

I remember reading an article recently that has something to do with headers and reverse lights not working.

Did the previous owner install these and forget to plug something back in?

 

[79TURBO]

I think so (?)

I remember reading an article recently that has something to do with headers and reverse lights not working.

Did the previous owner install these and forget to plug something back in?

View attachment 2054View attachment 2055

I think so (?)

I remember reading an article recently that has something to do with headers and reverse lights not working.

Did the previous owner install these and forget to plug something back in?

View attachment 2054View attachment 2055View attachment 2056

Yes, when you install headers, a bar link must get removed that runs to the steering column and control the rear lights.

I have the same here on my project car.

So I bought an aftermarket kit that connects to the shifter to rectify the issue.

I have not even installed it yet.

 

[Brosain]

Yes, when you install headers, they is a bar link that must get removed that runs to the steering column and control the rear lights. I have the same here on my project car. So I bought an aftermarket kit that connects to the shifter to rectify the issue. Actually have not even installed it yet.

I actually found a YouTube video where the guy gets a little switch and connects it to the shifter. It’s activated by an existing bolt when you put the car in reverse. You then run the pink and green wire down to it (I’m assuming from the neutral safety switch under the dash) and voila. I ordered the switch and it came in yesterday. So that will be next weekends project ??‍??

 

[79TURBO]

Yes, when you install headers, a bar link must get removed that runs to the steering column and control the rear lights.

I have the same here on my project car.

So I bought an aftermarket kit that connects to the shifter to rectify the issue.

I have not even installed it yet.

Firebird Central | 1968 - 1981 Firebird and Trans Am Neutral Safety / Backup Light Switch Relocation to Shifter Conversion Kit with New Switch, Quality Parts, Low Prices

Eliminate linkage issues by relocating the neutral safety / backup light switch from your steering column to the floor shifter. This switch conversion works with all TH-350 and TH-400 automatic transmissions. Includes mounting hardware, mounting instructions, detailed drawings and now includes a...

www.firebirdcentral.com

Found mine here.

 

[Seventy6er]

For future readers, here is the rod assembly in question (#8 may or may not still be present).