Transmission Replacement

[ccurzio]

This is probably a silly question since I'd likely never actually do it, but I'm curious about the feasibility of replacing the transmission/gearbox in a DeLorean. Now I'm not talking about replacing it with the same thing (that's obviously possible), I'm talking about popping the stock one out and upgrading it with something much newer.

See, I've been driving manual transmission cars for ages. My DeLorean is a 5 speed, my daily driver (Audi A4) is a 6 speed, my last daily driver (Audi A4) was a 5 speed, my car before that (VW Jetta) was a 5 speed... you get the idea. Thing is, I love the modern feel of the manuals that AREN'T my DeLorean. Smoother and tighter shifting just feels so much better, but when I'm driving the DeLorean it feels like I'm steering a goddamn U-Boat in comparison.

So how feasible is it to upgrade the DeLorean's manual transmission with something modern?

(Concours guys probably just shit themselves and started vomiting. I'm cool with that.)

[David T]

The most compatible replacement is a Porsche box but what you are thinking about is VERY expensive. There is a reason you do not see many different transmissions in Deloreans. Not many choices! In many ways it makes a lot more sense, if you are changing the transmission, to also change the motor. BTW you are not changing a transmission, it is a "transaxle". It combines the clutch, transmission, and final drive (differential).
David Teitelbaum

[Ron]

Is all of your external shifting mechanisms up to snuff...or that's not what bothers you?

[DMCMW Dave]

What you don't like about the DMC trans is all in the shift linkage.

If the linkage were redesigned with something that wasn't so sloppy, with real bearings, it would fix everything.

The slop and friction in the DMC linkage is the 4 squishy rubber bushings and the goofy pivot bolt setup. The trans is fine, and the shifter itself is really a decent design.

[David T]

I agree the shifter mechanism leaves a lot to be desired. Especially if it is worn or out of adjustment. My biggest peeve with the 5-speed is the gearing is not optimized to the PRV for the Delorean. You run out of first too quickly and 2nd is not a good match from 1st. I see the same mismatch in the Lotus too. I guess they had to take what Renault gave them, there are not a lot of gearing choices in the UN-1.
David Teitelbaum

[Chris4099]

I improved my shifter feel just by replacing a few of the bushings and the pivot bolt (biggest improvement as my old one must have been worn down a bit). Still not as nice as modern cars, but it was cheap and easy to do! Might be something worth trying first.

[Kevin]

What you don't like about the DMC trans is all in the shift linkage.

If the linkage were redesigned with something that wasn't so sloppy, with real bearings, it would fix everything.

The slop and friction in the DMC linkage is the 4 squishy rubber bushings and the goofy pivot bolt setup. The trans is fine, and the shifter itself is really a decent design.

I really like how the Stage III car shifted, it was very smooth, and Mike M said that everyone was saying that about that car. So was there anything in particular done to that car to improve the shifting, or was it just a case of refurbished linkage vs. everyone else's 30-year-old linkage?

[Delorean Industries]

What you don't like about the DMC trans is all in the shift linkage.

If the linkage were redesigned with something that wasn't so sloppy, with real bearings, it would fix everything.

The slop and friction in the DMC linkage is the 4 squishy rubber bushings and the goofy pivot bolt setup. The trans is fine, and the shifter itself is really a decent design.

I would think this could be done with a second cable and a bearing at the linkage. Something would still need to be present for the movement between the trans and linkage. Biggest issue would be upgrading on a car with worn engine mounts. ( IE the moving shifter some times present under accel and decel.

[DMCMW Dave]

I've thought about doing the linkage with little heim joints, but there is such a thing as being too direct. Done wrong you'd get lots of noise and vibration inside the car.

There is a way to do it, take apart a BMW linkage sometime.

[Delorean Industries]

Technically with the joints being on two different axis ( one horizontal one vertical) this would allow for the needed movement between components. I would have to think their would be a lot of drive line noise resonating through the tunnel with the insulators removed though.

[ccurzio]

Is all of your external shifting mechanisms up to snuff...or that's not what bothers you?

Everything with my shifting is fine (except for the second gear roll pin), I just really don't like how it feels.


What you don't like about the DMC trans is all in the shift linkage.

If the linkage were redesigned with something that wasn't so sloppy, with real bearings, it would fix everything.

The slop and friction in the DMC linkage is the 4 squishy rubber bushings and the goofy pivot bolt setup. The trans is fine, and the shifter itself is really a decent design.

I don't know enough about cars yet to have been able to articulate this, but I'll take your word for it. I just wish there was something I could do to make it feel more modern, more like my Audi. I know there's only so much you can do to a 30 year-old car, but that's kind of why I posted the thread. :)


BTW you are not changing a transmission, it is a "transaxle". It combines the clutch, transmission, and final drive (differential).

As mentioned, I'm not super car-literate just yet so thanks for the clarification. :)

[DMCMW Dave]

I don't know enough about cars yet to have been able to articulate this, but I'll take your word for it. I just wish there was something I could do to make it feel more modern, more like my Audi. I know there's only so much you can do to a 30 year-old car, but that's kind of why I posted the thread. :)
. :)

Shifter linkages in rear engine cars are difficult. Looking at most modern cars there isn't very much of a linkage at all, the shifter is typically mounted to the transmission (not the frame/body)and the linkage is either extremely short and direct or may even be internal to the transmission, with some sort of rubber isolation built into the lever arm itself.

Having driven many DeLoreans, I can say that there is quite a bit of variation from car to car and once in a while you hit one that just "feels right". One of these days I'm going to take one of those apart to see what is different, but so far I haven't had the time to take apart a "good" car as a science experiment. But I suspect that much of the issue is the pivot assembly, and maybe in the cable-ends but to me most of what you feel is the movement of the link rod ends and the pivot arm.

[Squall67584]

I'm not exactly sure how it works, but on my Acura and a new beetle we once had in the family, the shift linkage wasn't actual bars, but is what appears to be rubber insulted cables that were somewhat flexible. Several years ago when a friend of mine was looking into building a go cart with a 90's Honda motor/trans combo, there was a kit for this type of cable linkage since the engine would be behind the driver, and normally those trans had bar type linkage since the trans was at the rear of the engine bay in a Honda. Newer Honda's, including my Acura, have switched the direction of the engine in the bay so they now use the cables. I hope that was easy enough to understand since I don't know what the technical name for those cables are.

[David T]

The longer the linkage, the inherently more effort to move it. It also has more chance of vibration and looseness (play). I see the same problems in Lotus. They have tried several different variations over the years and none of them is what I would call satisfactory. Especially if they get a little worn or are not adjusted just right. Right can be 1/2 a turn or less. Lubrication is very important. Filing and "fetteling" (adjusting) to get all of the parts to fit with no play and still work smoothly is very important. Especially on the pivot bolt. Lubrication is also a big part of this. After 30 years any grease or oil that is still there is a sticky, gooey mess. If you are serious about getting the shifting (and the throttle) to work smoothly and properly you have to take it ALL apart, clean it all up, lubricate it, and adjust it. Any stickiness or rough spots and it won't feel right.
David Teitelbaum

[Squall67584]

I'm not exactly sure how it works, but on my Acura and a new beetle we once had in the family, the shift linkage wasn't actual bars, but is what appears to be rubber insulted cables that were somewhat flexible. Several years ago when a friend of mine was looking into building a go cart with a 90's Honda motor/trans combo, there was a kit for this type of cable linkage since the engine would be behind the driver, and normally those trans had bar type linkage since the trans was at the rear of the engine bay in a Honda. Newer Honda's, including my Acura, have switched the direction of the engine in the bay so they now use the cables. I hope that was easy enough to understand since I don't know what the technical name for those cables are.

So I got motivated and looked up what "cable shift linkage" is called, and it's called... cable shift linkage. Found a link to a GT40 site that someone gives an explanation as to how it works.

http://www.gt40s.com/forum/gt40-tech-powertrain-transaxles/21877-need-some-help-understanding-how-cable-shifter-works.html

I'm having a hard time visualizing that since I usually need to see it to understand it. But it makes me think that maybe something like the kit they describe for the ZF could be fabricated for the UN1?

[Ron]

Having driven many DeLoreans, I can say that there is quite a bit of variation from car to car and once in a while you hit one that just "feels right". One of these days I'm going to take one of those apart to see what is different, but so far I haven't had the time to take apart a "good" car as a science experiment.
+1

It's the same for a lot of cars (Fierros instantly came to mind ;-).
You can mark everything VERY well and put them back together and it feels different.
You can even take one end of one cable and tell sometimes, if it is your own vehicle.
Weird!

[Nicholas R]

I pushed my transmission forward 2" and it still shifts beautifully. I think it's mainly based on the quality of your linkages. I also rebuilt the transmission so that probably helps but I still think it's mostly the linkages.

The only transmissions I think would work in the DeLorean are the Porsche 915 and the Porsche G50.

The other transaxle transmissions I could see being used are Audi 016, Audi 01E, and the ZF from the Pantera; however, these can ONLY be used if you're able to flip the differential the way the 369/UN1 can.