It was just the gear oil...

"JayZAyEighty thinks C4+3=C7" (jayzayeighty)
07/25/2014 at 13:10 • Filed to: None

After changing the transmission fluids and OD unit filter as recommended by a transmission guy I know, the C4 is good to go and the 4+3 is actually a lot of fun. The gear oil was total shit, but I'd luckily bought some and got it over with immediately!

DISCUSSION (20)

RamblinRover Luxury-Yacht > JayZAyEighty thinks C4+3=C7
07/25/2014 at 13:37

The OD unit has a filter... well, herp my derp. That's just weird.

Rock Bottom > JayZAyEighty thinks C4+3=C7
07/25/2014 at 13:38

I'm still pretty geeked about your 7-speed Doug Nash... and jealous...

Glad to hear it's working as advertised now!

JayZAyEighty thinks C4+3=C7 > RamblinRover Luxury-Yacht
07/25/2014 at 13:40

Haha I thought so too, but it's basically just a powerglide at the back of a Super T-10 so it makes sense that it needs ATF and a filter.

JayZAyEighty thinks C4+3=C7 > Rock Bottom
07/25/2014 at 13:45

Thank you, that's the nicest thing anyone has ever said about my transmission. It's a neat unit but not nearly as functional as a 6 speed. I'm glad it doesn't have any big issues, though... it would be really expensive to fix! If your jealousy persists and you're in the DC area, you can feel it rapidly vanish as you use the 4+3 :)

Rock Bottom > JayZAyEighty thinks C4+3=C7
07/25/2014 at 13:48

I might take you up on that some day!

Flavien Vidal > JayZAyEighty thinks C4+3=C7
07/25/2014 at 14:39

Sucks I'm leaving to Japan soon... I would love to try the 4+3 also... Never have :)

Glad it was just that! The Zf6 transmission does not require to be flushed during its entire lifetime... I still did it for the sake of it, but it's fairly useless...

Axial > JayZAyEighty thinks C4+3=C7
07/27/2014 at 00:46

I wasn't kidding when I said all the 4+3 needs is regular fluid and filter changes. :p

JayZAyEighty thinks C4+3=C7 > Axial
07/27/2014 at 00:57

I bought the stuff, then the car sat for 3 months. Come registration day and the mandatory trip down a nice road, everything worked fine. The next day, I'm taking my sister down the street and it refuses to go into gear. Luckily I have it to my mechanic the next day (I don't have a jack or stands ATM) with the fluids in hand and it's a whole new car. The shifts are long and notchy but rewarding to get right. Next up is clutch fluid and diff oil, which I have. I'm just kicking myself for not bringing it to the shop once I figured out I didn't have the required tools. It's so versatile with such low highway engine speeds at the push of a button. The 4+3 is plagued by its owners from what I hear, and I'm one of those owners now I guess.

Axial > JayZAyEighty thinks C4+3=C7
07/27/2014 at 01:04

I dunno, you got it done and now it's working. A lot of C4s these days tend to be all DIY cars, and most DIYers will say "fuck it, replace with 5-speed" when the 4+3 "conks out."

I did read your other post about driving it on the highway. When you want to get on the gas, you really ought to clutch-in and turn off the OD unit before romping. Letting it work automatically as advertised is how it breaks.

JayZAyEighty thinks C4+3=C7 > Axial
07/27/2014 at 01:13

It just wouldn't be the same car without a 4+3. It's not as fast as the then-advanced 700R4, but it's a neat gearbox and it's manual so it ticks that box. I knew about clutching in for OD engagement and disengagement, but the automatic function took me by surprise when I stepped on the gas. I don't just hit the button for it without clutching in and I take it out before I press harder on the gas now. It was kind of cool to change lanes in OD and have it step down to reg 4th and really get out of it's own way when I wasn't expecting it, though. Improper use of the overdrive unit is definitely an Achilles heel from what I've heard. I won't be doing any serious driving with the 4+3, though, and the limitations of no AC during the summer and a floppy chassis with the top off limit how much I drive. A brace for the top will be next in line, it's so nice to be able to have the top off but a drag to (constantly) scan the road for every little imperfection ahead and have little rigidity.

Axial > JayZAyEighty thinks C4+3=C7
07/27/2014 at 01:19

I know what you mean about the floppity chassis with the roof removed. The car was not actually designed to have a targa top, but the overlords demanded one after the C3 had one so they retrofit it in.

While I have not looked into it much, the word is that the targa truss isn't manufactured by anybody any more, so you'll have to probably go searching for a used one or make your own. It's just four tubes bent and welded together (total of four welds) with holes for the targa screws; you could probably get a local shop to do it. I think material (steel vs. aluminum) is going to be the biggest factor in cost.

JayZAyEighty thinks C4+3=C7 > Axial
07/27/2014 at 02:16

I think we can thank Magnum PI and his trusty 308 for the black bordering and targa top inspiration, as T-tops were kind of a 70s thing I guess. It probably wouldn't be hard to have one made, but first I'll take a look around the interwebs for a used one anyways. It would be cool to have the underbody X-brace from a convertible and be able to have the top on in rain without much trouble, but I doubt I'd find one. For now I'll stick to maintenance items and deal with the floppiness, my only worry is putting too much stress on the frame.

Axial > JayZAyEighty thinks C4+3=C7
07/27/2014 at 02:53

Honestly? I never take the top off of my car. It has too many drawbacks in exchange for being open to the sky. I also think the car looks way better with the top on, but to each his own.

As for the rub strip...it was a new concept made possible by improving plastics. Almost every car had one! Then they went and derped it up after 1990 by making it body-coloured. What's the point of a rub strip if you have to repaint it after a scuff?

JayZAyEighty thinks C4+3=C7 > Axial
07/27/2014 at 03:23

I definitely agree on the looks. The car just looks awkward with the top off. It's just that I need to convert the air conditioning to R134, which is a better move than the truss I suppose. I guess I'll do that. As for the painted rub strip , it's completely pointless. The pre-refresh cars had fresh styling if nothing else with the round taillights, subtle rear spoiler and fended bulges, pointed nose with big lights mounted, and huge air dam that makes the car look awesome when parked on an incline. The 80's-ness of it all was a big part of the car's character. If nothing else, the targa top forced engineers to make the thick door sills creating the fall in, climb out experience that makes you feel like you put the car on. I think I'll be converting the a air conditioning before I get chassis reinforcement, though, because the car looks and feels much better with the top on.

Axial > JayZAyEighty thinks C4+3=C7
07/27/2014 at 03:34

That '80s-ness is half of the reason I want a ZR-1 to replace my '96, the other half being the wide body. If only they also came with the digital cluster! I suppose one could buy an '89 and convert it to ZR-1 wide-body (it's been done), but that would be a more expensive and time-consuming venture than just buying a ZR-1 and being done with it.

JayZAyEighty thinks C4+3=C7 > Axial
07/27/2014 at 04:03

Wow, the '96s are the best built from what I've heard, but I can understand wanting an older car. A ZR-1 widebody '89 with a ZF6 and the old interior with the leather sports seats and the usual L98 mods (intake manifold, exhaust, headers, runners, air filter and lid, cam, injectors, fuel pump, cylinder heads, and shorter gears) would probably outrun an LS1 C5 and would still be affordable and a classic. Plus, no need to worry about emissions or registration fees with its age being over 25. If the '89s were a little cheaper, that's a path I would love to take. It's still a simple pushrod corvette you could put guilt-free miles on but have the awesome looks of a 1990 ZR-1, digital dashboard, drivability and torque of an L98 but with respectable power, and roomy interior. Then again, the prospect of owning a ZR-1 for the same amount of money is probably reason enough to just go that route.

Axial > JayZAyEighty thinks C4+3=C7
07/27/2014 at 04:17

They are. Least bugs, least rattles, OBD II, LT4, blah, blah, blah. Still, any C4 post 1990 doesn't have that nostalgic punch I'm after.

Ugh. I hope I land a decent job once I graduate. I want to get that ZR-1 sooner rather than later, because prices won't stay down here at rock-bottom forever. Shoot, if the car runs I'd even prefer a salvage/rebuilt title so I can rag on it.

JayZAyEighty thinks C4+3=C7 > Axial
07/27/2014 at 04:33

A salvage ZR1 would make for an impressive hoonmobile indeed! The LT4s are pretty amazing, although, like you said, it's a matter of affordable classic vs affordable performance with the C4s. The reason I like the '85 is because when it came out it was the answer to the '84's problems and was a showcase of GM technology, so it's kind of special for me because of that. It feels like a flagship and something innovative from a bygone era, which gives it a great character. I never thought I own a corvette, either. But the LT4. That must be tons of fun.

Axial > JayZAyEighty thinks C4+3=C7
07/27/2014 at 04:48

The '85 was the fastest L98. They went from a 5.7 second car to a 6.2 second car for whatever reason in '86 and never recovered. Yup, even a 1990 L98 is slower than an '85, on top of having a less track-capable suspension setup. You have a great car, and in traffic it's just as punchy as mine. The daily driving advantages of the LT4 only become apparent at highway speeds because you can rocket away in second up past 65 mph due to the higher red line and flatter torque profile. Off the line, however, the L98 is more fun because it's got this awkwardly awesome torque spike at 2300-ish RPM. It just derps your head back into the headrest and off you go!

I guess you could say that the LT4 is almost too refined. The classic SBC firing order is all that separates it from an LS1 and is really the only thing giving it character. It's like the last "hurrah!" for the classic small block Chevy before it went full-modern. It's a better engine and a better car and I love it, no question, but my tastes have changed a bit since I got it.

JayZAyEighty thinks C4+3=C7 > Axial
07/29/2014 at 22:16

I have to say, there's more than adequate power under the hood in most situations. At 85 getting into the left lane of a fast highway, some top-end punch is left to be desired but with the cam and unobstructed K&N (it actually made a noticible difference because the stock setup is so restrictive) it will really get up and going quite well. All in all, it's a great combination of nostalgia and performance. The LT4 really are incredible and sought after, but if classic is what you're after they probably aren't going to satisfy your 80s fantasies. I have poly bushings, some chassis stiffening parts, and basic tune up stuff sitting around. After that, headers/exhaust and maybe new fluids all around (diff, clutch, brakes, power steering, etc) and maybe some tires, it will pretty much be ready for track days. The top end punch of an LT4 might not be usable on most days, but in the middle of nowhere or at a road course it's a pretty nice proposition. Anyways, good luck attaining the king of the hill! Those are drool worthy machines.