Automatic vs manual T in regards to speed

[sitopons]

OK I have a question regarding speed. I believe all automatic transmission vettes from 1984 to this day have a 4speed auto trans available yet the manual transmission is quite different from years 1984 through 2007. I think the 2008 model might no have auto trans available only manual....Corvette went from a 4 speed to a 6 speed in manual transmission and skip the 5th gear except for the 4+3 fiasco, why did the automatic trans not follow the same route??????

thanx for listening

 

[Toms007]

Not sure I follow you entirely, but I'll add to what you have posted. Four speed auto transmissions have been the norm for many years. Where as the Manual has gone through some major changes. In the C6 they have even gone to a 6 speed auto transmission. No the autos are not the only trans available, but standard and autos are still offered.

Not sure why it took so long to get the 6 speed autos.

 

[Hib Halverson]

Some of the beliefs expressed in the lead post are incorrect.

Corvette automatic transmissions had four speeds from 1984 to 2005. From 2006 to 2009, the auto is a six-speed.

The 84-88 Corvette had a four-speed manual with a two-speed electro/hydraulic overdrive. Corvettes from 89 to 09 have had six-speed manuals.

From 84 to 09, both a automatic and a manual trans have been offered.

 

[CharlesBrown]

I didn't know my 4+3 was a fiasco. I thought it works just fine!

 

[sitopons]

I didn't know my 4+3 was a fiasco. I thought it works just fine!

Some mechanics had complaint about it and some owners as well. It seems that that transmission does give out after some time, it needs rebuilding and cause a lot of headaches and money when trying to repair it. Chevy tried to meet emissions standards when they just should have gone for the 5 speed an meet emissions and reliability.

 

[sitopons]

auto vers manual T

Has anyone driven a 6 speed manual T and a 4 speed automatic T of the same model and year and find any differences as far as torque/power. Could you share with us your experiences driving both cars.

Thank you

 

[TedC]

I've driven 1989s with a 6 speed and auto. Wanted the 6 speed, but after driving it for a few days, settled for a 1989 with auto and high performance rear axle. Test reports had them running similar in 0-60 and 1/4 mile runs. For me, the 6 speed did not feel like the right match for the low reving high torque L98 engine. I find it a much better match to an engine like the LT1 that has a wider usable RPM range. If you decide on an auto, find one with the high performance axle. Minimal impact on MPG, and adds some real excitement in 1/8 mile runs.

 

[Hib Halverson]

Some mechanics had complaint about it and some owners as well. It seems that that transmission does give out after some time, it needs rebuilding and cause a lot of headaches and money when trying to repair it. Chevy tried to meet emissions standards when they just should have gone for the 5 speed an meet emissions and reliability.

1) The problem with the 4+3 (or, as it was known inside GM back then, the "Doug Nash") was not the gearbox section which was, basically, a beefed up Warner Super T10. The problem was the electro-hydraulic overdrive which was POS and cost GM millions in warranty costs. It took GM and Nash (which was bankrupted by the project) until 1987 just to get it tolerable. The overdrive was a prime-example of customers doing GM's product development.

2) The reason the Doug Nash existed was not meeting exhaust emissions standards. GM could have done that with the four-speeds it used previously. The problem was fuel economy. The 84 Vette needed the computer controlled overdrive to meet CAFE.

3) In the late-70s/early-80s when the 4+3 was under development, there was no five-speed in existence which would handle the torque of a 5.7L V8. So, GM and Doug Nash cooked up the computer-controlled overdrive unit for the C3's existing four-speed. In fact, there continued to be no five speed like that. That's why, for 1989, Corvette went to the ZF S6-40 six-speed.

 

[FISHAWK]

Auto Vs Manual

Has anyone driven a 6 speed manual T and a 4 speed automatic T of the same model and year and find any differences as far as torque/power. Could you share with us your experiences driving both cars.

Thank you

I agree with TedC on his point, An engine with a peakier (Higher RPM )powerband need more gear ratios to stay in its torqueband ,where engines like the L98 and LT1 do not.

 

[JimBobC4]

I have driven an LT-1 Vette with both an automatic and a Six speed.
I currently own an LT-1 6 speed.

The six speed is faster off the line than the auto. I guess the lower gear ratio in the rear helps here. This off the line 0 - 60 performance was what convinced me to go with the 6 Speed. A quick run down an on ramp is about all your going to get away with around here.

Also, the 6 speed has a stronger rearend than the auto in C-4's. Thats something to think about as well.

If you drive on the track at all, or even if you like the twisties up in the mountains, I recommend the 6 speed.

The L-98 is a different story. I've driven both of those and the automatic L-98 was a nice driver. While the 4+3 tends to make the engine seem to labor a bit. L-98's don't rev real well when compared to an Lt-1 or LS-1.
I don't think they are really suited for a manual transmission ( except to do some really cool burnouts !)

In the end, its a matter of choice. I would drive BOTH before I decided upon one or the other.

 

[air1jpg]

Some of the beliefs expressed in the lead post are incorrect.

Corvette automatic transmissions had four speeds from 1984 to 2005. From 2006 to 2009, the auto is a six-speed.

The 84-88 Corvette had a four-speed manual with a two-speed electro/hydraulic overdrive. Corvettes from 89 to 09 have had six-speed manuals.

From 84 to 09, both a automatic and a manual trans have been offered.

I believe the '82 C3 also had a 4 speed auto transmission, was it the same auto that was put in the '84?

 

[Hib Halverson]

I believe the '82 C3 also had a 4 speed auto transmission, was it the same auto that was put in the '84?

Yes.

 

[tcxd40]

Has anyone driven a 6 speed manual T and a 4 speed automatic T of the same model and year and find any differences as far as torque/power. Could you share with us your experiences driving both cars.

Thank you

I have a 6 speed and auto, both 93s, both black. The stick in my opinion is not as responsive as my auto. 1st gear sucks, belongs in a truck, power is great in 2nd and 3rd, 5th and 6th are worth less unless on the highway. The auto lunches right off the line without hesitation effortlessly. Power and torque seem more available with the auto than the 6 speed.
tcxd40