Gen 1 Differential Fluid Change

[jkroberts21]

Progressing with changing all the fluids but when I got to the differential, according to the service manual's directions, I attempted to withdraw the fluid with a suction tool, but the fluid seemed way too thick to **** out. I did let the car sit for a few hours after driving it, but the 75w-140 amsoil I bought to replace the fluid was way thinner

There appears to be a drain plug in the bottom of the diff. Can the fluid be drained that way?

Can anyone who's changed the differential fluid in a gen 1 give me some advice on procedure?

Much appreciated in advance

 

[Steve-Indy]

That drain should work.
As you might guess, draining it hot (with care) helps when dealing a differential without a drain. I like to put in a little new fluid, as a rinse, then drain or suction that fluid out before final fill.

 

[steve e]

A bit of advice, before you drain any transmission, differential, transfer case, make sure you loosen the fill plug first, I can't tell you how many cars have been towed into my shop because the owner couldn't loosen the fill plug after he drained it, they can be over tightened and a bear for the home mechanic to get loose.

 

[maverickagm]

Does anyone know the drain plug socket size? A 1 inch box-end wrench feels a tad loose. I suspect it might be 25mm (1 inch = 25.4mm).

Also, I second checking the fill plug first! I had to use a 3/8" hex socket on a breaker bar. Don't attempt to use any other socket that has even a little bit of wiggle.

 

[maverickagm]

Update: It is a 3/4-16 UNF plug, otherwise known as an 8AN ORB (o-ring boss) plug. I ordered an aluminum one and torqued it to 15ft/lbs.

A 1 inch socket is required. Does anyone know what type of pipe plug this is?

Mine is missing the o-ring and I deformed it a bit when removing it. The threads look parallel instead of tapered and the pipe plug is made of aluminum.

 

[efnfast]

I was going to do the differential fluid on my Gen 2 shortly ... I don't recall seeing a drain plug on mine ... that's weird they would have given it to a Gen 1 and not gen 2 since drain plugs make the job so much easier.

 

[maverickagm]

I was going to do the differential fluid on my Gen 2 shortly ... I don't recall seeing a drain plug on mine ... that's weird they would have given it to a Gen 1 and not gen 2 since drain plugs make the job so much easier.

I don't think Gen 2 has drain plugs from factory. That's what some threads seemed to indicate when I was searching for the thread size. It's weird, but I guess that's just what they did. For Gen 1, there's even part numbers. 4626712 = "Plug, Pipe". 4626713 = "Washer, Plug Seal".

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[daveg]

Gen II = No Drain Plug.