C4 Corvette 4+3

In this video I try to explain the workings of the C4 Corvettes Manuel 4+3 Transmission. A very misunderstood and unique engineering of the time.

[@adventureswithbuckarugh3682]

Thanks Michael. I have never seen such a good explanation of the workings of the 4+3 manual transmission. I never realized there was any difference from year to year. I think i would drive it the same as you. Just a 4 speed and an overdrive for highway mileage. I used to drive a truck for work with a two speed rear end and that ended up being the way I drove that truck. I have a pair of 92s that I am planning to make into one fine machine. The stick shift car is wrecked but runs and drives the other one (automatic) i think was someone else's donor car. To many mismatched and missing parts. But the body is decent. I hope to start posting videos on my progress in the future.

[@kussstuff]

1992 was a good year for the C4 , with the LT1 motor came out. Having a pair of 92s of them to make into one is going to be a cool project, I look forward to watching. Thanks for the comment.

[@jimirox1928]

I Agree 100%

[@limabravo6065]

And i love how people will spunk themselves silly gushing over a gear vendors under over unit and how it can "split gears" and they think that a bolt on overdrive is some radical new idea. Borg warners been at it since at least the 50s and maybe earlier

[@limabravo6065]

I want one of these transmissions for my Camaro, its different and my uncle had one when i was a kid and being the type of kid who pulled everything aprt to see what was up the 4+3 was like crack to a crackhead for me

[@famasmaster2000]

Just subscribed my friend. Good channel 👍

[@kussstuff]

Thanks for the sub! I truly appreciate it.

[@CorCam-vc2tr]

Hello Michel, I am from Switzerland and bought a Corvette 1986 L this spring. It has the 4+3 manual transmission. I have only driven 1500 km. I thought that when I shift into second gear and it automatically engages the overdrive that it makes a mistake with the electronics. Now you say that it shifts directly into 2,5 gear at a speed. This is the same system as the C6 where it shifts you directly into fourth gear. That could have been the pioneer, in a sense. When I go to a US car meeting I only see C4 automatics, this manual transmission is unknown in Switzerland. But I could talk to people who know the gearbox and rated it positively.

[@kussstuff]

First off -- Hello from the United States. There is a lot of confusion on the 4+3 Trans, because all years are not the same, so often you get different answers for the same question. Thats why I put a graft at the end of the video to show the differences. They are a good transmission, basically their a T10 four speed with a OD. Thanks for the comment.

[@nikkoalpha2]

For those looking at C4 automatic models, look for one with av3:07 rear differential instead of the standard 2:56 rear differential. The Doug Nash 4+3 transmission is so misunderstood by many folks. Maintenance is key with this manual transmission. Ignoring this can be costly.

[@kussstuff]

Good info. Thanks for the comment

[@nikkoalpha2]

⁠@@kussstuff I enjoy your videos on the first gen C4 models. I currently own a '96 Collector Edition, but owned a '87 convertible for more than 13 years. The C4 generation is a great value for first time Corvette buyers. It provides a rawer drivng experience than later generations. And not too crazy powerful, excluding the lower production ZR1 and Callaway models, than newer generations.

[@kussstuff]

@@nikkoalpha2 Your '96 Collector Edition that's awesome. These are special cars which drive like no other. Thanks for sharing.

[@vikingtrad3r]

I agree that the 4+3 is an awesome transmission. Maintain the fluids and u r good to go. No synthetic in the OD unit. An 86 4+3 was my first track car and it was perfect. I had amazing fuel economy on the way to the track, then simply turn OFF the OD at the track! Im not sure why so many people take issue with it. Its awesome. Oh, i always use the clutch when i engage and disengage the OD.

[@kussstuff]

I also think the C4 makes a great track car with the 4+3. Sounds like you proved it. Thank you for your comment.

[@vikingtrad3r]

@@kussstuff please keep the c4 related content coming!

[@Maxreverse]

Mike great videos. I own a 1987 C4 with the Nash 4+ 3. Love it. What are your recommendations for the proper fluids to change the transmission?

[@kussstuff]

Corvette overdrive unit-Moblel 1 DEXRON-IlI. and the T-10 4 speed SAE- 80-90 gear lubricant. (Synthetic oil not recommended)

[@Maxreverse]

Thanks for the info Mike. I’m planning to change them both soon.

[@user-xc6tg4cf7b]

Hello Michael. I am the original owner of a 1988 4+3 with 41,000 miles. Runs great, except for the automatic overdrive stopped working sometime ago. It does not work when you want to accelerate and pass someone without manually downshifting. It will work, however, when I manually engage the button on the shifter. Not sure what the issued could be. I read somewhere else that it could possibly be a relay under the hood on the firewall, but I cannot figure out which one it is. Supposed to be a a low cost ($35) part to try. Any suggestions. Thanks!

[@kussstuff]

I really wish I could help you on this one, but this is when I wish I had a full-service transmission manual. I do have a number of service manuals for my corvette and will look through and if I find anything that would help I will let you know. But you may want to try some of the C4 Facebook groups if you haven't already. Good Luck!

[@vhp454]

This transmission wasn't designed to be abused. It was basically an old mans transmission. Best to replace it with borg super T 10 with out the od or plain fact get a muncie M 22.

[@kussstuff]

When they went to the ZF 6-speed manual transmission, all things got better.

[@vhp454]

@@kussstuff The ZF 6 speed is better. But there is no replacement for the muncie M22

[@kussstuff]

👍

[@ZZ48UUP]

There's nothing wrong with "slamming automatics." No one who considers themselves an enthusiast drives an automatic. Period. I always heard great things about the Doug Nash 4 + 3 as long as you drove the car properly. I have only owned 5 speeds and a Tremec however.

[@kussstuff]

I think we agree there is no better way to be one with the car then a manual transmission. Thank you for the comment.