Transmission / Overdrive: 4-speed transmission for 230 ci Chevrolet Six

[avantilover]

I'm considering changing the transmission in my 66 cruiser six cylinder from 3 on the tree to a 4 on the floor as I can get a transmission here in Australia.

Just wanted comments from those who know about such things, is it a good idea? I imagine the extra gear makes it better to drive?

[stude dude]

Is the existing 3 speed transmission an overdrive?

Chris.

I'm considering changing the transmission in my 66 cruiser six cylinder from 3 on the tree to a 4 on the floor as I can get a transmission here in Australia.

Just wanted comments from those who know about such things, is it a good idea? I imagine the extra gear makes it better to drive?

[avantilover]

Yes, according to the original topic it's 1 of 8 with a 230 Six and Overdrive. Is first gear un synchronized? Would be fun to learn the double de-clutch gear change I guess.

[stude dude]

Stick with the overdrive, lots of fun when you learn how to use it properly and very economical. And you can slip them back to first as you coast to a stop light if you are careful!

Chris.

Yes, according to the original topic it's 1 of 8 with a 230 Six and Overdrive. Is first gear un synchronized? Would be fun to learn the double de-clutch gear change I guess.

[avantilover]

Stick with the overdrive, lots of fun when you learn how to use it properly and very economical. And you can slip them back to first as you coast to a stop light if you are careful!

Chris.

Thx, will do, can always rebuild the tranny if I stuff up 1st gear. Am sure it's easy to shift.

Appreciate the advice.

[41 Frank]

From my standpoint if you change over from a 3 speed overdrive to a 4 speed your fuel economy and top speed will suffer greatly as you will now have a 1 to 1 ratio top gear. In other words the same ratio as a 3 speed without using the overdrive. Overdrive equipped cars have a lower rear end gear so if you do change to a 4 speed a rear gear ratio change would be in order. Overdrive is much preferred for highway cruising in my opinion.

[swvalcon]

You could look for a I think a 4 or 5 speed from a mid 80's chev pickup that was overdrive in high gear. It would stand up to the 250 six as they put it in the low hp v8's.

[gordr]

What the others said. If the car already has overdrive, it's a lot easier and cheaper to make that work than it is to change to a 4-speed. Lack of synchronized first gear is really not a problem, because on flat ground you can often start in second gear. Rarely will you have to downshift into first on the fly, but the freewheeling feature makes that fairly easy anyway. If the existing OD is completely trashed, a 5-speed would be a good replacement. A four-speed box would kill your highway gas mileage.

[lark55]

I don't know if this is a reasonable answer, but if you could find one of the saginaw three speed overdrive transmissions you would get a synchronized first gear. I drove a 66 carryall with a 283 3spd., o.d., 4:11 rear gear for a number of years and was happy with it. There is also a conversion that would allow you to use a 4 speed saginaw with o.d. This was detailed in Hot Rod magazine a number of years ago (mid-80's?).

[avantilover]

Ok, thx for the advice, will keep the car as it is.

[1962larksedan]

Another option to consider would be a BW T5 5 spd stick; it would give you 4 'regular' ratios and an overdrive one...........all synchro.

[avantilover]

Due to Government regulations I'd be unlikely to be able to use a 5-speed as it wasn't available at the time.

In any case, I'll consider all options upon its arrival, but keeping her original is the cheapest option.

Many thanks for the advice, much appreciated.

[StudeRich]

For gosh sakes John, do the Feds over there tear these cars apart and match the remains to a Spec sheet or something trying to find a non-original part? They must be as Socialistic as Canada!

[hausdok]

For gosh sakes John, do the Feds over there tear these cars apart and match the remains to a Spec sheet or something trying to find a non-original part? They must be as Socialistic as Canada!

Nah,

Just this guy. He runs the office that will be receiving John's car.

[StudeRich]

Another Bad link Mike.