Author Topic: 1976 Eldorado auto trans issue  (Read 1323 times)

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Offline Matman

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1976 Eldorado auto trans issue
« on: November 11, 2016, 06:49:57 PM »
Hi All, you too Bruce,
I thought I`d just jot this down as a record of what my issue is and also as a record of what I have done.
A while back I realised my Caddy was not upshifting to top gear. I`ve had the car about two years and prob only done 1000k in that time.
The problem was intermittant, I`d go to a car show one week - all good, two weeks later another show... no upshift.
next couple of days out it would be ok... or not..
I removed the V/mod, checked it out, even checked operation with vacuum pump. all good.
A few days later I removed the governor to check operation, all good, very clean, no sticking valve etc.

TODAY I checked enging vacuum - running at 15hg, bit low I thought, so checked vac hoses, found one off on the thermal switch neat the t-stat housing.. reconnected and secured that, I found a couple of other hoses that were suspect so I have decided to relace All vac hoses asap. But right now , no leaks and vac reading is at 19/20 hg.
..I tested the vac mod supply by fitting a `T` piece at the mod and running a hose with vac gauge att into the car. still 19/20 reading. Good
Bye the way, the trans fluid level is correct, nice and clean, no funny colors or smells.
Just before I dropped the car down, I decided to see what adjustment I might get from the V/Mod, I turned it three full turns A/clockwise.
TEST DRIVE.
I drove for about ten K round the suburbs, It was upshiftinging nicely, I was grinning ear to ear.. then I decided to turn back and go home. Half way back it was just the same as before. Hmm not happy.

I should say I have always managed to get it into top gear by either speeding up to about 40/50MPH, or flicking it into neutral, giving it a good rev then dropping back into drive.
I hope someone might have an idea or two I could follow up on,
cheers Matt.



Offline Bruce Reynolds

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Re: 1976 Eldorado auto trans issue
« Reply #1 on: November 11, 2016, 10:30:09 PM »
I would be suspecting the Vacuum Modulator, but what would I know about Auto Transmissions.

I would be actually having a chat to an Auto Transmission specialist and listen to him.

Bruce. :devil:
Bruce Reynolds, Lindisfarne, TASMANIA
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
(Past President Modified Chapter)

Offline Matman

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Re: 1976 Eldorado auto trans issue
« Reply #2 on: November 12, 2016, 09:14:59 AM »
I suspect you know more than most Mr Reynolds. ha.

As far as talking to auto guys, been there done that, unfortunately the talent for diagnosing issues seems to be dissipating into the wind, the general concensus is that a `complete rebuilt` is the answer.

Most car guys / owners are like you and me, we have gained a lot of knowledge over the years, I have rebuilt a few auto trans myself.. but that was 40+ years ago. Thats why by turning to forums like this someone might just drop a little info that refreshes our memory banks and hey presto problem solved...................... Sometimes..  :cheers:

Offline Bruce Reynolds

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Re: 1976 Eldorado auto trans issue
« Reply #3 on: November 12, 2016, 11:27:41 AM »
Sounds like the Auto Transmission shop might actually know what needs doing, but as for me, I send all my transmission work to my mate in Melbourne.

I don't have the tools required to mess with these things, plus, when pulling them apart, they make so much mess, and my workshop is not set up for the cleanliness of transmission work.

But, having said that, I have seem guys at the drags strip and rebuild a powerglide during race-day, with dust going everywhere.

Bruce. :devil:
Bruce Reynolds, Lindisfarne, TASMANIA
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
(Past President Modified Chapter)

Offline Jeepers Creepers

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Re: 1976 Eldorado auto trans issue
« Reply #4 on: November 13, 2016, 06:18:51 AM »
Hey Matt,

Have a talk to Bob Grant.

Very smart man where autos are concerned.
He use to build/service my 10 second street car C4 trans and the 7 second drag car powerglide.

http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0ahUKEwiJstLE9qPQAhXONpQKHULMABEQFggrMAM&url=http%3A%2F%2Fwww.bgaauto.com.au%2F&usg=AFQjCNHjVSdAg62AQS7k4TfLU9bCOaw8LQ&bvm=bv.138493631,d.dGo
Kev and Astrid.
1964 Fleetwood.
First time caddy owners

Offline Bruce Reynolds

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Re: 1976 Eldorado auto trans issue
« Reply #5 on: November 13, 2016, 09:16:26 AM »
Sounds like good advice to me, plus he is in Brisbane, close to you.

Bruce. :devil:
Bruce Reynolds, Lindisfarne, TASMANIA
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
(Past President Modified Chapter)

Offline Matman

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Re: 1976 Eldorado auto trans issue
« Reply #6 on: November 15, 2016, 04:32:28 PM »
Hi Guys,
well I spoke to Bob this morning, we chatted for a while, threw a few ideas back and forth but as he says , I`ve done everything he would have done to find a fault.
Removed cleaned and checked operation of V/ M and Governor. Adjusted V/M, Checked Vacuum level with a `T` pice at V/M end. Checked vacuum level at carb. All read 19/20hg.
Disconnected kickdown switch at Carb end, plus disconnected V/M for separate test drives.
Tomorrow I`ll do the accelerator pump which need doing anyway and while I `m at it I`ll triple check and replace any suspect Vacuum lines.

Offline Bruce Reynolds

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Re: 1976 Eldorado auto trans issue
« Reply #7 on: November 15, 2016, 07:48:28 PM »
Sounds like it might end up being a rebuild?

Bruce. :devil:
Bruce Reynolds, Lindisfarne, TASMANIA
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
(Past President Modified Chapter)

Offline Jeepers Creepers

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Re: 1976 Eldorado auto trans issue
« Reply #8 on: November 16, 2016, 06:41:53 AM »
Hey Matt,

Bob's a nice guy huh.

Kev and Astrid.
1964 Fleetwood.
First time caddy owners

Offline Matman

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Re: 1976 Eldorado auto trans issue
« Reply #9 on: November 16, 2016, 03:46:28 PM »
Hey JC.. YEAH, NICE GUY, He certainly was up for a good chat to see if we could resolve the issue over the phone, I said when I have the carb setup properly and doubled checked all the vac hoses I`d take it to him for a hands on check.