My 68-er Delmont is on the road again after 20 years storage and I have to say there aren't many problems at first sight!

But... since I'm driving on the highway the engine runs a bit high.
Tried to search it out and there seems to be a 3 gearbox installed, but when I drive I hear and feel it only go to the second gear at about 50 miles a hour. At that time the car is so (wind)noisy its hard to hear more and no tachometer installed.

I'm also wondering if there is an overdrive?

I also do hear a rattling sound when fast accelarating, its stops after trottle down. When the car is in Park position, I don't hear this sound...


Please let me know because I think there is someting wrong in the gearbox (although transmission runs very smooth to the second gear)

Thanks!

 

Does your shifter show PRNDL or PRNDSL?

If it's DL, you have a two-speed automatic transmission. DSL is a 3-speed automatic. Neither of these transmissions have overdrive.

I think your rattle is spark knock or detonation. These engines were made for high-octane gasoline. Don't know how readily available that is in Europe now.

 

I thought in '68, Delmonts were only made with the TH400, with 3 speeds.
The only other trans available would have been the TH350, also with 3 speeds.

Corrections, anyone?

- Eric

 

I think you are correct. I don't think the 2-speed Jetaway was used in any full-size Olds except the Jetstar 88, and that may have been only for 1964, but I'm not sure about that.

 

Hope this helps.

 

I have to squint to read it, but it does show the Jetaway as an option on the Delmont.

 

Well I'll be...

 

Pretty sure the Jetaway was offered in the small-block / 350 equipped '68 Delmonts (as was the case with the 330s in 1967). However the car in question appears to have a 455 based on other posts by Nicole.

Nicole, you posted THIS pic previously, so perhaps you can check the shift indicator pattern to tell for sure as previously suggested to determine if you have a 2 or 3 speed trans.

1968Delmont88Holiday14.jpg

Its hard to make out, but I'm PRETTY sure I can make out "RNDSL" ("Park" would be out of shot over to the far left), thus making it a 3 speeder.

 

Once you open the attachment, click on the picture again, it should get a little bit larger.

 

Yep, that pic is mine and it shows: PRNDSL

So she has a 3 speed transmission (and NO overdrive)
Solved!

I think your rattle is spark knock or detonation. These engines were made for high-octane gasoline. Don't know how readily available that is in Europe now.

Hmmm, rocketraider.
First I thought I would need an transmission rebuilt but your answer is quit possible. I drove the Delmont (rocket 455) about 300 miles on Dutch gasoline, what we call "Euro 95 lead free" and seems to be the same as "91 Premium".
Do I need some additive or a booster? Whats your opinion?

Searched: https://classicoldsmobile.com/forums...-vs-today.html and http://tech.classicoldsmobile.com/44.shtml

Or maybe the ignition?

 

Well, since you asked, the TH350 was not available until the 1969 model year.

 

Check your ignition timing first.

 

Thanks, will do!

 

And so I did!

Wow, great advice although nobody wanted to believe me!
Timing was set earlier and she drive's like NEW!! Just a small rattle left, will handle that in a short time.

Thanks you all!

 

To clarify:

1968 Delmont came standard with a 250hp 350 & manual transmission on the column.

Engine/Trans options:

310hp 350 (L74): M31 (Jetaway) or M40 (TH400) required.

310hp 455 (L30): Manual Transmission or M40.

320hp 455 (L66): M40 required.

365hp 455 (L31): M40 required.

M31 - Jetaway was a $205.37 option.

M40 - TH400 was a $236.97 option and suggested for any 350 with trailer package.

 

For $31 more dollars why would anyone want a two speed? I've had a Powerglide and a Jetaway and I haven't been impressed with either. In fact three weeks ago I put the TH400 in. I'll have it off the jack stands soon and can't wait to feel that old familiar TH400.