transmission choices hj47 + h42 + h55 + fairey (1 Viewer)

Joined
Feb 13, 2008
Messages
24
Location
surf coast, Australia
Hello All, I am in the process of doing some repairs to my HJ47 Troopy, the roof and sides are off and the head as been reco etc. My old 4 speed had some semi nasty bearing noise for the last 2 years and the gear float is now out of tolerance. I am almost certain that the bearing noise was the input->main shaft roller bearings (noise practically went away in 4th (input:main is 1:1) and was loudest in R and 1st (input:main is -4.3 or 3.5:1), this was tested with the T/Case in neutral, so I assume the noise is not from the T/Case. Gearbox still changed well and didn't jump out of gear.

Anyway I am probably going to buy a second hand 5 speed + fairey OD from a HJ60 this weekend because I want to get better hwy rpm. The possible combinations I have are 4sp + F, 5sp + No F or 5sp +F. From memory the 2H with standard wheels in 4th gear sat on about 2800rpm at 100 km/h (screaming its titties off!). 4th in the h42 is 1:1, the 5th gear in the H55f is 1:0.845 and the Fairey in OD is 1:0.787 (1:1 not engaged). Which gives me this table (assuming I was correct with 2800rpm at 100km/h)

100km/h 120 km/h​
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4th | 2800rpm 3360rpm
5th | 2366 2840
4th+F | 2204 2645
5th+F | 1862 2234

I want advice to make the best educated choice given my possibilities. The downsides to keeping the 4 speed is have to at least replace the input shaft and input->main shaft bearings, and perhaps put in new thickness circlips to address the out of tolerance float. The downside to putting in the 5 speed is I will have to change shaft lengths and adjust the floor cover panel, and I don't know the condition of it. The downside to the fairey is it's ancient with no spare parts and I lose the transmission parking brake.

At the moment I am leaning towards putting the whole new transmission (5speed + F) in and changing shafts. But 1862 rpm at 100km/h is probably overkill. I guess I can drive around in 4th + F a lot of the time. Also having an extra stick in the floor would be fun (which is totally the wrong reason to want an OD).

What would you do?
 

AussieHJCruza

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Joined
Jul 8, 2013
Messages
1,866
Location
New South Wales, Australia
I would be somewhat wary of the Fairey, I understand it can be difficult to get parts for them, although there is something cool about lots of gear sticks.
Also, you might find yourself going back gears for hills - easier to have 1 gear stick to shift (unless you've got 3 arms)
Hope some of this makes sense.
 

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