Author Topic: Change from 4 to 5 speed box  (Read 527 times)

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Offline Triton

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Change from 4 to 5 speed box
« on: Monday,June 17, 2024, 12:13:34 PM »
I have a 73 Special with a 352 gearbox. I would like to change to a 5 speed. Is there any  box that i  can fit with no modification needed to the chassis and would use the same gear change bars. Car has a standard chassis .  Thanks  Stuart....

Offline BDA

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Re: Change from 4 to 5 speed box
« Reply #1 on: Monday,June 17, 2024, 01:38:06 PM »
I believe the 365 is the closest to what you want. I believe the rear section of shift linkage would need to changed or lengthened and you'd need the 365 rear mounting plate and mounting bushings but I suspect they are very difficult to come by.

I've seen an NG3 mounted in a 352/365 frame (the rear hoop had to be hammered to make clearance). Presumably Richard at Europa Engineering could supply the rear mounting brackets and hardware but the shift linkage would have to be replaced with Richard's linkage (presumably he could make that for you too - I don't see it listed separately) but installing that linkage would probably be best done with the engine out. Several people have rigged a cable shift setup with good success. There are plans and pictures around so with some fabrication help (I'm assuming you would need it) it would not be THAT difficult and an NG3 would be easier to find than a 365 but I think they are getting a bit difficult to find now a days.

Still others have installed a 395 tranny but unfortunately, I can't help you at all with what's required for those and I don't know their availability.

I think those are the easiest options for converting a 4 speed to a 5 speed since they either require the least amount of custom fabrication or the parts that do need fabrication are documented somewhere. Unfortunately, after a 365, things get much more complicated.

If I've missed other good options, somebody please chime in.

Offline 4129R

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Re: Change from 4 to 5 speed box
« Reply #2 on: Monday,June 17, 2024, 01:53:09 PM »
I am driving both a TC with a 4 speed box, and a TCS with a 5 speed box.

The main difference on the 5 speed, the gear ratios are closer together, with 4th at 15mph/1000 and 5th at 21mph/1000.

On the 4 speed box it is 18mph/1000 rpm.

It is worth the effort and the cost?

Offline Triton

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Re: Change from 4 to 5 speed box
« Reply #3 on: Monday,June 17, 2024, 01:55:28 PM »
Thanks BDA for the information, i did not think i would be able to get away with it that easily but i thought i would ask,  It sounds to be a really big number so i won't bother. My 352 box is good and quiet and seems oil tight at present.  Thanks Again Stuart..

Offline Clifton

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Re: Change from 4 to 5 speed box
« Reply #4 on: Monday,June 17, 2024, 03:07:30 PM »
I am driving both a TC with a 4 speed box, and a TCS with a 5 speed box.

The main difference on the 5 speed, the gear ratios are closer together, with 4th at 15mph/1000 and 5th at 21mph/1000.

On the 4 speed box it is 18mph/1000 rpm.

It is worth the effort and the cost?

This ^

I thought about swapping a lighter although weaker Toyota gearbox in mine over the summer, 37lbs lighter but then thought long on why and do I really want the hassle? Mine works well even though it could be better.

Offline Dilkris

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Re: Change from 4 to 5 speed box
« Reply #5 on: Tuesday,June 18, 2024, 01:42:15 AM »
I have a 73 Special with a 352 gearbox. I would like to change to a 5 speed. Is there any  box that i  can fit with no modification needed to the chassis and would use the same gear change bars. Car has a standard chassis .  Thanks  Stuart....

Please find following photo's of a 365 (5 Speed Gearbox) as fitted to a TCS within a standard chassis - these photo's should help you appreciate what is involved in an attempted to change from a 352 transaxle.
As already well advised - the real benefits of such a change are questionable.

Offline Bainford

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Re: Change from 4 to 5 speed box
« Reply #6 on: Tuesday,June 18, 2024, 08:28:18 AM »
I am driving both a TC with a 4 speed box, and a TCS with a 5 speed box.

The main difference on the 5 speed, the gear ratios are closer together, with 4th at 15mph/1000 and 5th at 21mph/1000.

On the 4 speed box it is 18mph/1000 rpm.

It is worth the effort and the cost?
How does the differential ratio compare between the two boxes?
The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

Trevor

Offline jbcollier

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Re: Change from 4 to 5 speed box
« Reply #7 on: Thursday,June 20, 2024, 12:59:15 PM »
There are three chassis for the TC: 336 only, 352 only and the last which takes either a 352 or 365, just uses a different mounting bracket.  The last is "easy" to switch from one to the other.  The first two will require fabrication.

Offline Triton

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Re: Change from 4 to 5 speed box
« Reply #8 on: Friday,June 21, 2024, 11:54:43 AM »
Thanks everyone for the advice and comments, I am going to keep with the 4 speed box  ,I don't want to get involved in too big a job, I will just have to get out of the habit of going for 5th gear while driving.  Stuart....