Technical Fill plug locations for trans & diff??

[Mattymatt888]

I need some help identifying the transmission and rear differential fill plugs.

It seems like the fill plugs for both the trans & diff are almost impossible to get to (assuming I’ve identified the correct plugs).

The first two images show the suspected transmission fill plug as green, which seems to be blocked by the exhaust, and the drain plug as red.

The third image show the rear diff fill plug as green is hidden behind the panhard bar, the drain plug as red and top vent as blue.

Have I identified the plugs correctly? Any advice on how to properly change the fluids? I have a 1978 spider 1800.

 

[bugsymike]

Other may give more precise advice but from memory of working on Ladas in the late 1970s (Fiat 124 under license) your green marks are correct and a 17mm combination spanner did the level plugs (slide up between gearbox and exhaust pipe, tricky when hot) and the same 17mm ring spanner slide up between Panhard rod and rear of differential.
Drain plug was a 13mm Allen key.
The level plugs in both cases are slightly lower than the middle of Diff and gearbox respectively.
If no leaks you should be able to prove my thoughts by undoing the green plugs and oil should be felt just below filler plug threads.
If you examine the start of those threads you may see that they are tapered to seal the hole rather than a gasket or washer.
I believe it was a straight SAE 90 grade oil in gearbox and the SAE 90 EP in the axle so don't put EP in gearbox.

 

[s130]

The plags are certainly tapered. Over time the threads wear a little so a couple of turns of some plumbers PTFE tape sorts out any weeping.

 

[Mattymatt888]

Other may give more precise advice but from memory of working on Ladas in the late 1970s (Fiat 124 under license) your green marks are correct and a 17mm combination spanner did the level plugs (slide up between gearbox and exhaust pipe, tricky when hot) and the same 17mm ring spanner slide up between Panhard rod and rear of differential.
Drain plug was a 13mm Allen key.
The level plugs in both cases are slightly lower than the middle of Diff and gearbox respectively.
If no leaks you should be able to prove my thoughts by undoing the green plugs and oil should be felt just below filler plug threads.
If you examine the start of those threads you may see that they are tapered to seal the hole rather than a gasket or washer.
I believe it was a straight SAE 90 grade oil in gearbox and the SAE 90 EP in the axle so don't put EP in gearbox.

Thank you for the concise explanation. Your advise seems to be consistent with others. I will definitely invest in a combination spanned or another thin tool to help access the 17mm fill bolt. From what I’ve read the drain bolt is likely a 12mm hex. I plan to use Napa’s GL-1 bear oil (part #65201) in the transmission and Valvoline’s 80W-90 GL-5 EP (part# VV831) in the rear diff.

 

[bugsymike]

Thank you for the concise explanation. Your advise seems to be consistent with others. I will definitely invest in a combination spanned or another thin tool to help access the 17mm fill bolt. From what I’ve read the drain bolt is likely a 12mm hex. I plan to use Napa’s GL-1 bear oil (part #65201) in the transmission and Valvoline’s 80W-90 GL-5 EP (part# VV831) in the rear diff.

I thought it was a 13mm Allen key for drain, but it was a long time ago.
Not sure about those oils without looking it up.