Help on changing transmission and differential fluids

[emircea]

Hello; I have an '77 Manta B which started to run again in october 2006, after an engine and some body rebuild.

Now, with summer almost back where I live, it is time for fluids exchange - gear box and differential, then the brakes.

Can you help me, please, with some pictures and more details? It is the first time I do this to an Opel and I didn't notice any regular drain and fill plugs neither on gear box, neither on differential (on Ford Escort and Renault are quite accesible and easy to spot)...

My gear box is always dirty with oil, seems to leak (viewed from behind to front) on the left side, where some part of the gear lever goes in... also, in the same area I noticed something similar to a fill plug...

To the differential, on a quick view, I didn't notice any drain or fill plug, so your advice is more than welcome!

I intend to pre-lube the plugs or bolts prior to removal with some rust unlocker, WD40 is available here an I used it many times before with good results.

What kind of oil do you recommend? Usual 80W90 for the gear boxes (both on gear box and differential), or something from Castrol, Aral or other brand names? Don't forget I'm from Europe, some U.S. products may not be available here.

Thank you in advance.

[opelnut10]

The transmission and diff. have no drain plugs, you must take the cover loose on the bottom of the transmission and the diff. cover bottom bolts to drain. If you take the transmission cover all the way off be careful and not loser the spring, ball and button that goes in the hole on the pan rail, that is your reverse detent ball and it keeps the transmission from jumping out of reverse when backing up. The transmission has a fill plug on the driver's side of the transmission and the diff. cover has a fill plug in the rear cover. Both of these plugs usually have a allen head instead of a hex head. I use 80W90 in both and mix it with 1 can of STP fill both until you get lube to just start coming out of the bottom of the fill hole with the car sitting level.

[emircea]

Thank you;

I'm not familiar with the 'allen' term, but I think i'll figure it out. Is it square or similar?

STP is simply the oil additive? As I observed, the only available product from STP where I live is the oil additive.

[David McCollam]

Hi,

STP is an oil additive that is a thick lube supporting agent. The product you have in your area is the same STP as in the US.

A "hex" or "Allen" wrench is a 6-sided bent piece of metal. The Volkswagon transmission drain uses the same style of socket adapter. You may be able to find one of those if you have a VW shop close by.

Good luck.

Dave

[emircea]

Ah, hex! Thank you! That's doable!

Do you recommend greasing or lubing anything else?

Thank you in advance!

[Paul]

What's the purpose for putting STP in the tranny or differential? Inquiring minds.......

[tekenaar]

The transmission and diff. have no drain plugs, you must take the cover loose on the bottom of the transmission and the diff. cover bottom bolts to drain. If you take the transmission cover all the way off be careful and not loser the spring, ball and button that goes in the hole on the pan rail, that is your reverse detent ball and it keeps the transmission from jumping out of reverse when backing up. The transmission has a fill plug on the driver's side of the transmission and the diff. cover has a fill plug in the rear cover. Both of these plugs usually have a allen head instead of a hex head. I use 80W90 in both and mix it with 1 can of STP fill both until you get lube to just start coming out of the bottom of the fill hole with the car sitting level.

. . . just wanted to make sure that you understood that only the center bottom diff. cover bolt ("thru-bolt") needs to be removed to drain differential . . . you don't have to remove diff. cover, only the center bottom bolt. It's best to do both immediately after everything's up to operating temp (driving car) . . . oil's thinner and drains quicker!

[opelnut10]

What's the purpose for putting STP in the tranny or differential? Inquiring minds.......

Cause it slick, at least that's what Richard Petty said when he was peddling it. By mixing STP with gear lube you create less friction, which creates less heat and makes the gears run smoother it also helps if you get a little low on lube. It's like Bill Dance says about spray on bait scent, it might not help but it don't hurt nuttin

[emircea]

Well, thanks for the tips...

I have checked today under the car and I can tell you that:

-the bolts on the gear box plate are M10 hex head and I assume the thread is M6;
- the gear box fill plug is something with hexagonal head, between M12 and M13; I assume I shall use an adjustable wrench if it's not too tight;
- the screws on the diff. back plate seem (but not sure) to be M13 hex heads.

I have a few more questions and thank you in advance for your patience and understanding...

- does it hurt if, instead of STP, I use Liqui Molly engine additive? this one is too for engines, gears, axles, diff's... and I already have it...(I already know that this may be a thicker mineral oil, but this helps me buying just 2 liters of oil and the rest up to 2,2 - 2,4l is the additive)
- as I remember, I need ~1,1 liter for each gear and diff.; am I wrong?
- how can I pour the oil by myself easier, as I have no help available and make not too much mess? I have a slope 1,5m high where I can place the car, then stays horizontally and I have some space underneath...Do I need a longer hose and lots of patience to pour the oil?
- before the new oil, shall I wash the mechanisms by pouring some diesel fuel or gasoline?

Anyway, I am a little upset; the car is leaking oil from both oil pan gasket and the gear box and today I managed to break the first bolt from the passenger side of the oil pan trying to tighten it to press harder on the gaskets... Now I have to remove the oil, the oil pan, bore the remaining of the bolt in the center with a 3 mm drill and then use the appropriate bolt extractor... and take care to the thight space...

The gear box is leaking slowly almost everywhere: gear cover gasket, from the side levers, from the area where it connects to the clutch cover... and the bad thing is that I have to fix them by myself, the mechanics around here are not very skilled and patient (and neither am I, the difference is that I do the job for myself)... Wish me * luck and maybe this year is ready, not leaking anymore...

[namba209 (R.I.P.)]

Patience, extreme patience is needed to use a screw extractor. They are very brittle and will break if too much torque is applied. Then you'll have to remove it with a carbide grinding bit. Hopefully you took the torque off the broken bolt when you snapped off the head.

[opelwasp]

Just don't use Slick50: Quaker State Ads For Slick 50 Are False And Misleading, FTC CHARGES

More good sites for info on oil additives
The Engine Oil Bible : Additives
Slick 50 and other ail additives

[soybean]

I have always used Lucas Oil Stabilizer and some of their other products in my
vehicles and have been very satisfied here. emircea, I don't know if you can find it where you are. Hth, Jarrell

[emircea]

Thank you guys for your suggestions.

Still one questions remains: shall I wash the mechanisms by pouring some diesel fuel or gasoline? Did anyone do this before?
We still use diesel fuel or gasoline in cleaning sludged parts, as degreasers; diesel fuel especially leaves everything clean, but slightly lubricated; can this do any harm? The service history of my car is nonexistent, so I assume the worst* - the fluids have never been changed since it left the factory.

Thank you in advance.

[emircea]

Hello, guys;

Thanks for your answers, I finished almost everything this week-end one hour and half ago.

I couldn't take the broken screw out without damaging the threads, so I moved to next size (M8) for that. I put some red silicone to the gaskets (high temp one); to have enough clearance for the oil pan, I'll put the pictures tomorow with the device I used to lift the engine (now attached).

Fluids were successfully changed in the gear box and differential, as per your advices. I washed the mechanisms with diesel fuel, as this is a good cleaner and leaves things slowly lubricated.

The only thing left is to watch the gear box and fix the leaks; I put there some red gasket silicone, too, and I hope this is the answer... Otherwise, I have to take it down in the near future. Not to mention that I lost by a bit the opportunity to have another gear box (used one), shift lever and clutch cover toghether with only 80$...

Thank you once again.

Emilian