76 Cadillac Tranny

[brent covey]

> I've been told
>it has a '76 Caddy transmission.
>
> Is that good or bad? Anyone know if this
>automatically makes it a switch pitch?

The transmission is the same basic unit used in the GMC, however there may
be some small changes- the final drive on the vast majority of Eldorados is
a 2.73, with the GMC 3.07 optional which was in a few units. The internal
parts are pretty much the same, small changes may be present in the valve
body to make it smoother and more 'Cadillac-y' but its pretty much the
same, and should last about as well.

Cadillac's 500 Engine was used with this transmission, its a good strong
transmission. It will not have a switch pitch converter, and the regular
Cadillac converter is a slightly lower stall speed than a GMC would have
come with. This means its a direct coupling at a slightly lower engine
speed, which is a small difference. The main difference you probably will
discover is the speedo gears may have been retained from the Cadillac,
which will make it inaccurate, thats about all.

I wouldnt let it put you off the GMC a bit if it drives well in other
respects.

Hope this helps-

Brent

 

[steve canyon]

You bet! That helps a bunch -- thanks, Brent. I
was told that it has an 1800 RPM stall speed --
forgot to mention that. Is that what you would
expect for this transmission/converter? I also
have the impression it uses the original final
drive, but I could be mistaken in thinking that.

Regards,
Steve

>
> The transmission is the same basic unit used in the GMC, however there may
> be some small changes- the final drive on the vast majority of Eldorados is
> a 2.73, with the GMC 3.07 optional which was in a few units. The internal
> parts are pretty much the same, small changes may be present in the valve
> body to make it smoother and more 'Cadillac-y' but its pretty much the
> same, and should last about as well.
>
> Cadillac's 500 Engine was used with this transmission, its a good strong
> transmission. It will not have a switch pitch converter, and the regular
> Cadillac converter is a slightly lower stall speed than a GMC would have
> come with. This means its a direct coupling at a slightly lower engine
> speed, which is a small difference. The main difference you probably will
> discover is the speedo gears may have been retained from the Cadillac,
> which will make it inaccurate, thats about all.
>
> I wouldnt let it put you off the GMC a bit if it drives well in other
> respects.
>
> Hope this helps-
>
> Brent

 

[brent covey]

Steve writes-

>You bet! That helps a bunch -- thanks, Brent.

You're welcome!

> I
>was told that it has an 1800 RPM stall speed --
>forgot to mention that. Is that what you would
>expect for this transmission/converter? I also
>have the impression it uses the original final
>drive, but I could be mistaken in thinking that.

Yes, 1800ish sounds about right- in '75 GM went to very low stall
converters in most car lines and Cadillac was no exception, all done in the
name of efficiency. The difference is very minor and the lower stall will
tend to keep the oil cooler in the transmission generally at some small
tradeoff in performance. The GMC and most trucks use a converter that
stalls about 300 rpm higher. Stall speeds are difficult to pin down with
precision, as with enough power they stall at higher speeds- so lets just
say with the same engine, the Caddy converter stalls a few hundred rpm
earlier than the original GMC;-)

Hope this helps

Brent

 

[steve canyon]

Thanks Brent -- that gives me a pretty good
perspective on it. Transmissions are something I
haven't messed with since my 55 & 57 Chevy hardtop
days...

Regards,
Steve
Coachless in Denton

>
> Yes, 1800ish sounds about right- in '75 GM went to very low stall
> converters in most car lines and Cadillac was no exception, all done in the
> name of efficiency. The difference is very minor and the lower stall will
> tend to keep the oil cooler in the transmission generally at some small
> tradeoff in performance. The GMC and most trucks use a converter that
> stalls about 300 rpm higher. Stall speeds are difficult to pin down with
> precision, as with enough power they stall at higher speeds- so lets just
> say with the same engine, the Caddy converter stalls a few hundred rpm
> earlier than the original GMC;-)
>
> Hope this helps
>
> Brent