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Converted or Factory 4 Speed?

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Old Nov 27, 2018 | 06:39 AM
  #1  
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Converted or Factory 4 Speed?

Hi Everyone - how can I tell if my 1971 Oldsmobile Cutlass S came with the 4 speed transmission from factory or if it was converted?

Thanks in advance.
Konrad




Last edited by konrad; Nov 27, 2018 at 06:42 AM.
Old Nov 27, 2018 | 06:52 AM
  #2  
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Maybe hard to tell without paperwork and if PO did a factory conversion swapped from another car? I would get underneath and look at cut out for floor hump, linkage, wiring, console and other evidence. Olds engines were specifically auto or 4 spd due to the rear of the crank being drilled to accommodate pilot bearing. There is a a conversion available without machining crank but still have to modify input shaft of trans.
Old Nov 27, 2018 | 07:19 AM
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Most of the stuff to convert from auto to manual trans is bolt on, the only thing I can think of that would be a small bit of work would be to properly weld the bracket for the "Z bar" to the frame under the area of the master cylinder. Like scrappie said, look at the areas he mentioned & maybe get some pictures of those areas for us to look at. Also I think the transmission should have a VIN derivative on it that will or will not match part of your VIN. I'm not a manual trans. expert & am not sure if or where these VIN numbers should be.
Take a look at the clutch/bake pedal cage & see if it looks newer/older/rustier/less rusty than the rest of the under dash pieces.
Old Nov 27, 2018 | 07:52 AM
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Is the VIN stamped on the transmission?
Does the speedometer have PRND21 on it?
Is there a functional (or the remains of) a neutral start switch on the clutch pedal?
Does the steering column have the remains of a column shifter on it?
Do you have all the back drive linkage to turn on the reverse lights when the transmission is placed in reverse?
How is the positive battery cable routed?
What does the battery tube and bracket look like?
Does the rear axle ratio match the standard transmission in this post? 1971 Rear Axle Ratios
One or two piece driveshaft?
There are probably more indicators.

The answers to the questions above should give a better indicator if it's original. The best is obviously if the transmission matches the VIN.
Old Nov 27, 2018 | 07:58 AM
  #5  
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Originally Posted by oldspackrat
Most of the stuff to convert from auto to manual trans is bolt on, the only thing I can think of that would be a small bit of work would be to properly weld the bracket for the "Z bar" to the frame under the area of the master cylinder.
The bracket is a bolt-on part for the 1968-72 cars. The holes are pre-drilled in every frame, above the location of the distribution block/combo valve.

Bottom line is that there is almost no way to know for sure if the conversion was done properly. The factory cutout for the shifter looks like it was poorly done with a torch on production line cars, so that's no giveaway. Of course, if the hump for the shifter boot is not spot welded to the floor pan, or if the crank is not drilled and there's a conversion pilot bearing, that's an obvious give-away. If the crank was properly drilled and the parts were properly installed, there's pretty much no way to know. One thing you MIGHT look at is the driveshaft. Manual trans cars used a solid driveshaft. AT cars used a shaft made from concentric tubes with rubber in between. If the car was converted and they re-used the TH350 driveshaft, that's evidence against it being factory. Also, look at the accelerator pedal. If the pedal has the tab for the TH350 kickdown cable and the firewall has a square hole where the cable used to come through, that's also evidence.

And of course, the easiest thing is to check the VIN derivative stamp on the trans. If it matches the VIN of the car, that's the best proof you'll ever get.
Old Nov 27, 2018 | 08:00 AM
  #6  
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Hard to tell from pictures, as suggested above, shifter hole smoother or rough cut. No prn2l on dash under speedometer. The shifter boot on console is incorreclyt installed, think it was mounted underneath console.
Old Nov 27, 2018 | 08:02 AM
  #7  
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Thank you all. I thought that there would be an indicator number, or letter, in the VIN, but I can't find any info on this.
I will check first to see if I can find the vin on the transmission and if not, to look further into what you've all mentioned.
To answer some of the questions V8al posted
- the speedometer does not have the auto trans indicators
- I can start the car without clutch depressed
- reverse lights do turn on in reverse
Again, the rest I will verify. It either is the factory 4 speed, or someone went into great lengths to make it look like the factory 4 speed.
Old Nov 27, 2018 | 08:05 AM
  #8  
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Originally Posted by classicmuscle.442
Hard to tell from pictures, as suggested above, shifter hole smoother or rough cut. No prn2l on dash under speedometer. The shifter boot on console is incorreclyt installed, think it was mounted underneath console.
The shifter boot on the console is definitely aftermaket, I was thinking because of the hurst shifter probably.
Old Nov 27, 2018 | 08:06 AM
  #9  
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Originally Posted by joe_padavano
And of course, the easiest thing is to check the VIN derivative stamp on the trans. If it matches the VIN of the car, that's the best proof you'll ever get.
Is there a specific area on the transmission would I would find the VIN derivative stamp? Or is it random?
Old Nov 27, 2018 | 08:09 AM
  #10  
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A few more things.


A factory AT car with floor shift would not have the PRNDSL on the speedo anyway.
A factory MT car would have a backdrive linkage from the trans to the steering column. This is what would operate the backup lights.
A factory MT car would have a fourth gear switch on the trans to operate the Transmission Controlled Spark system
A factory MT car would have had a clutch safety switch and the purple wires for the starter circuit would plug into it.
That's an aftermarket Hurst shifter boot, not factory.
The factory shifter uses a snap-in stick. Aftermarket shifters use a bolt-on stick.
The correct factory shifter is unique to console cars and looks like this:



The VIN derivative stamp is located here:
Old Nov 27, 2018 | 08:15 AM
  #11  
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Let me add that just because the car doesn't have the original trans or shifter doesn't mean that it ISN'T an original 4spd car, it just makes it much more difficult to verify. My 70 W-30 is a factory MT car, but when I got it the engine, trans, and shifter had all been replaced. The backdrive linkage was long gone to clear headers.
Old Nov 27, 2018 | 08:15 AM
  #12  
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Thank you. I will take a look at the transmission stamp.
Old Nov 27, 2018 | 09:22 AM
  #13  
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Told ya, these guys know their stuff!
Old Nov 27, 2018 | 09:38 AM
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Does cowl tag call anything out in these years?

Were there extra frame braces on manuals?
Old Nov 27, 2018 | 10:29 AM
  #15  
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The VIN on my factory 4speed car was stamped on top of trans..
Old Nov 27, 2018 | 10:42 AM
  #16  
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Joe is right on the VIN number stamped on the transmission. A build sheet is also 100% rock solid.

I converted my 70 442 from manual to 4 speed. I used 100% factory parts, and had a donor floor template to cut the floor.

Except for the VIN number, every single detail from the FSM and Assembly Manual were followed.

It can be done, but is not "numbers matching".
Old Nov 27, 2018 | 10:47 AM
  #17  
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Only thing some what related on a cowl tag would be if it originally had bucket seats from the factory. Though you could get a standard transmission with bench or bucket seats.
No extra braces unless the FE2 suspension package was ordered, which you could get with either transmission.
Old Nov 27, 2018 | 08:28 PM
  #18  
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Another tip off is if the console has the rear lamp with the frosted lens that faces out towards the back seat. MT cars do not have this feature. But to me, Joe's previously mentioned note about the accelerator bell crank is one of the best things to look for. It would take someone really knowledgeable and focused on the details to change it out if the car was a AT to MT conversion.
Old Nov 27, 2018 | 08:44 PM
  #19  
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Originally Posted by joe_padavano
The bracket is a bolt-on part for the 1968-72 cars. The holes are pre-drilled in every frame, above the location of the distribution block/combo valve.

Bottom line is that there is almost no way to know for sure if the conversion was done properly. The factory cutout for the shifter looks like it was poorly done with a torch on production line cars, so that's no giveaway. Of course, if the hump for the shifter boot is not spot welded to the floor pan, or if the crank is not drilled and there's a conversion pilot bearing, that's an obvious give-away. If the crank was properly drilled and the parts were properly installed, there's pretty much no way to know. One thing you MIGHT look at is the driveshaft. Manual trans cars used a solid driveshaft. AT cars used a shaft made from concentric tubes with rubber in between. If the car was converted and they re-used the TH350 driveshaft, that's evidence against it being factory. Also, look at the accelerator pedal. If the pedal has the tab for the TH350 kickdown cable and the firewall has a square hole where the cable used to come through, that's also evidence.

And of course, the easiest thing is to check the VIN derivative stamp on the trans. If it matches the VIN of the car, that's the best proof you'll ever get.
Hey Joe I looked in the assembly manual and you are right about that bracket being a Bolt on. I know I have seen them welded on on some cars do you know when they made it a bolt on item?

Another possible clue would be the 2 holes in the fire wall where the throttle cable and kick down cable may have came through. In the hole marked 12 if it was a manual transmission car or a Turbo 400 car there would be no kick down cable and there should be a black square plastic plug pushed into place in this hole.

Old Nov 28, 2018 | 10:12 AM
  #20  
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Originally Posted by oldspackrat
Hey Joe I looked in the assembly manual and you are right about that bracket being a Bolt on. I know I have seen them welded on on some cars do you know when they made it a bolt on item?

Another possible clue would be the 2 holes in the fire wall where the throttle cable and kick down cable may have came through. In the hole marked 12 if it was a manual transmission car or a Turbo 400 car there would be no kick down cable and there should be a black square plastic plug pushed into place in this hole.
My early 68 442, TH400, AC car doesn't have a cover over these holes. Funny I just remembered looking at this last night tending to my battery tender...lol
Doesn't look like it ever did? Mr Pack do you have a pic of said plug for the two holes??? Dont recall seeing this reproed either?
Just when you think you've learned most everything something new pops up. I dont think I have ever seen this plug on a 68-9. But I never paid attention till now. I was the first one to restore my 68 back in 86. This was a very complete well cared for unrestored car. No plug present then. Wouldn't be the first anomaly on this early build Z code 68.
Old Nov 28, 2018 | 10:18 AM
  #21  
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I have a 1972 U code 4 door parts car at my warehouse. I was just over there today grabbing some parts and looked at that fire wall and said I should take a picture of that and then promptly forgot about it. I'll try to do that the next time I get over there.
Old Nov 28, 2018 | 12:57 PM
  #22  
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Originally Posted by droldsmorland
My early 68 442, TH400, AC car doesn't have a cover over these holes.
No 1968 A-body has these holes. The TH350 didn't exist in the 1968 model year, so there was no need to punch a hole for the kickdown cable. The two available transmissions (ST300 and TH00) both used an electric kickdown.
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