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52 car guy 05-27-2008 07:38 AM

66 Olds Toronado
So I have this 66 Olds Toronado, the first year of front wheel drive. I am in the process of changing the front differential fluid and am wondering what type of fluid I should put back in it. What came out of it was not gear oil....much thinner.. From what I have read the frist two years 66-67.. this olds used a plantiary system.. then in 68 they switched to a ring and pinion. I looked in my Chiltons and all it says is to use "special fluid number" then it has a number that means nothing to me. Have visited dealerships and no-one seams to know.. thought someone here might have run across this. Any help would helpful

Thanks in advance

j-jock 05-27-2008 01:06 PM

Toranado fluids
I had a 67, and still have the shop service manual. GM lists the fluid for the final drive as GM part number 1050015 or equivalent.
The 67 final drive is described as a ring and planetary gear system, so I can only assume that it would take the same fluid.

Give this web site a try.

52 car guy 05-27-2008 01:31 PM

Thanks for the response... I found that number also the only problem I am having now is deciding is tha gear-oil or A.T.F. Being that it is a planatary gear set-up? none of the dealers around here have a clue...

j-jock 05-27-2008 02:06 PM

Final drive fluids
It is almost certainly a gear lube. The reason I say that is because of the ring and pinion assembly. I would use the 75-90 Amsoil synthetic gear lube. It has 4 times the film strength of a standard gear lube, and yet it pours almost like oil. I have been using synthetics in all my applications for over 26 years with excellent results.

52 car guy 05-27-2008 02:39 PM

well that exactaly what I was thinking but then beacue they use a planatary stytem and not really a ring and pinion it threw me a little. Unless I am not understanding what the manual is saying about the planatary system setup.

j-jock 05-27-2008 02:49 PM

66 Olds Toronado
When you look at the picture, it becomes clear. There is a ring and pinion assembly which drives the planetary system.
I am looking through some of my other books to see if I can get another number for the lube.

j-jock 05-27-2008 04:12 PM

66 Toronado lube
By looking through my old lube manuals, I was able to find that the GM part number of the lube for the final drive is a gear lube. I was not able to determine the viscosity, but by using the synthetic lube, you will be exceeding the capabilities of a 60s gear lube.

Jmark 05-27-2008 05:03 PM

Is the diff isolated from the trans? Hate to see the trans get some 80-90 in it! Might not shift too good.

j-jock 05-27-2008 05:08 PM

66 Olds Toronado
Yes, the final drive is a separate unit bolted to a TH425 transmission. The TH425 is just the Toronado version of the TH400. It, of course, uses ATF.

Crosley 05-27-2008 07:40 PM

I built a front wheel drive 1970 Chevelle with a 1966 Toronado front sub frame clip.

The final drive is separate form the trans. I used gear oil in the final drive unit.

As I a side note: I had a 6-71 blown small block chev adapted to the t-425 trans axle. The 66 t-425 should also be a switch pitch converter transaxle.


j-jock 05-27-2008 07:55 PM

66 Olds Toronado
Yep, once you have driven a TH 400 with the 2 stage converter, the regular THs just don't measure up. If I was to make just one modification beyond adding a shift kit to a TH400, that would be the one. Kenny Bell used to sell a conversion kit, but it wasn't a big deal to convert to a 2 stage converter.

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