12HT 5Spd into 82 HJ47 (1 Viewer)

[JethroBodine]

So, I am entertaining replacing the 2H 4Spd with a 12HT 5Spd.

I’ve been searching the threads and coming up with bits and pieces of information on swapping a 12HT in place of the 2H. Does anyone know if there is a comprehensive thread or list of ALL that is involved and how to accomplish it? Everything, all the little details. Including, but not limited to below. I don’t know all the questions to ask, so I hope you can tell me what I’m not asking…

Motor:
Fuel pump turns off via vacuum instead of electric?
Fuel return line required to the tank?
Radiator/fan changes?
Glow plugs vs Glow screen? – I have a manual button now if that is helpful
Throttle cable?
Wiring differences?

Trans:
Will the 2H bell housing bolt up to the 12HT & H55?
Does the 4spd cross member work with the H55 seems like I have seen conflicting answers on that.
If I can get a 40 series top for the H55 does that mean the trans hump doesn’t need to be cut/ modified?
Can my parking brake still remain at the back of the transfer case?
Wiring differences?

Thanks in advance for your help!

 

[ERNRAM]

@orangefj45

 

[duncanrm]

• Transfer case handbrake will foul on that round tube cross member
• 40 series H55F top cover is virtually unobtainable
• Glow screen is rarely needed for starting - if ever - your existing push button could be used to trigger it.
• Wiring all the same, starter, oil pressure, temp etc all the same
• Shutdown can be converted to a pull cable if you dont want to dick about with a complex vacuum system
• Your 2H bell housing will work just fine.
• Your existing transmission cross member will work just fine
• Radiator/fan all the same
• Are you going to HJ60 power steering at the same time (radiator outlet will need mods if you do).
• Be sure to take your engine mount arms off your 2H and reattach to the 12HT
• 5 speed upgrade is massively overrated and more trouble than its worth in my opinion.
• How confident are you in the 12HT condition? Most are just about ready for rebuild when purchased, piston ring land issues especially common.

 

[orangefj45]

• Transfer case handbrake will foul on that round tube cross member
• 40 series H55F top cover is virtually unobtainable
• Glow screen is rarely needed for starting - if ever - your existing push button could be used to trigger it.
• Wiring all the same, starter, oil pressure, temp etc all the same
• Shutdown can be converted to a pull cable if you dont want to dick about with a complex vacuum system
• Your 2H bell housing will work just fine.
• Your existing transmission cross member will work just fine
• Radiator/fan all the same
• Are you going to HJ60 power steering at the same time (radiator outlet will need mods if you do).
• Be sure to take your engine mount arms off your 2H and reattach to the 12HT
• 5 speed upgrade is massively overrated and more trouble than its worth in my opinion.
• How confident are you in the 12HT condition? Most are just about ready for rebuild when purchased, piston ring land issues especially common.

Great info and I agree with the vast majority.

We have 40-series top covers.

5-speed is a nice upgrade but requires some mods …..

We’ve done a very similar build.

Georg @ Valley Hybrids @ Cruiser Brothers

 

[duncanrm]

H55F - Rear tail shaft will have to be shortened, front tail shaft will have to be lengthened.

 

[Gimme a 60]

I did this into a 62 with a 3B.

I wish I remember all the small details, but it wasn’t difficult.

 

[JethroBodine]

Thanks for the responses!

duncanrm:
Transfer case handbrake will foul on that round tube cross member - Is there a way to add e-brake to existing rear drums, or just use a big rock?
40 series H55F top cover is virtually unobtainable - If I can find one, am I correct trans hump does not need to be modified?
Glow screen is rarely needed for starting - Is that base on an ambient air temperature range?
Are you going to HJ60 power steering at the same time? - No, I would go with electric power steering

orange45:
5-speed is a nice upgrade but requires some mods - can you elaborate? I know the drive shaft lengths need to be modified. What else? linkage?
We’ve done a very similar build - Was there a build thread per chance?

Thanks again all...

 

[ceylonfj40nut]

You can swap in a 70 series semi float or full float which has rear ebrake capability. Add cable and lever.

 

[duncanrm]

Thanks for the responses!

duncanrm:
Transfer case handbrake will foul on that round tube cross member - Is there a way to add e-brake to existing rear drums, or just use a big rock?
40 series H55F top cover is virtually unobtainable - If I can find one, am I correct trans hump does not need to be modified?
Glow screen is rarely needed for starting - Is that base on an ambient air temperature range?
Are you going to HJ60 power steering at the same time? - No, I would go with electric power steering

• Yes, with a 40 series H55F top cover .. no trans hump modification
• The common modification in Australia for the handbrake option is 60 series brake backing plates on your existing diff housing. This gives you a 60 series handbrake
• Glow screen: based on Australian conditions - reportedly the 12HT starts just fine even down around a few degrees below 0deg (Celcius), regardless, it'd be a simple wiring job to get it working
• Electric power steering.. well, not a fan - but I dont even run power steering at all and cope just fine.

 

[JethroBodine]

• Yes, with a 40 series H55F top cover .. no trans hump modification
• The common modification in Australia for the handbrake option is 60 series brake backing plates on your existing diff housing. This gives you a 60 series handbrake
• Glow screen: based on Australian conditions - reportedly the 12HT starts just fine even down around a few degrees below 0deg (Celcius), regardless, it'd be a simple wiring job to get it working
• Electric power steering.. well, not a fan - but I dont even run power steering at all and cope just fine.

Thanks again for your help.

IF I did power steering i would go electric. I haven't seen negative reviews, have you?

The more research I do I'm coming to the conclusion that I should just leave the 4 speed and not mess with the 5 speed. Maybe then the item I'm still unclear on is what you do with the fuel return line?

 

[duncanrm]

IF I did power steering i would go electric. I haven't seen negative reviews, have you?

The more research I do I'm coming to the conclusion that I should just leave the 4 speed and not mess with the 5 speed. Maybe then the item I'm still unclear on is what you do with the fuel return line?

H41 is a very honourable and rugged box.. much respect. The H55F is good, but not great.

I really dont trust the 5th gear much at all on the H55F - I also have an HJ60 with that box and really don't use 5th very much at all (very flat terrain over 100kph is about it).

I have heard mixed responses on the 12HT fuel return to tank - people claim that if you copy the 2H approach with the return line T'ed into the Lift Pump inlet its very difficult to prime, others claim its much the same as the 2H and primes right up. I would run without the return line and see how you go on the first attempt to prime it.

I'm sure the electric power steering pumps are fine - just on principle it makes me cringe a little, an old school diesel engine and all.

 

[JethroBodine]

This is what I'm referring to on steering: This and E-Steering Install

 

[duncanrm]

This is what I'm referring to on steering: This and E-Steering Install

Oh right.. I had assumed you mean electric pump into a minitruck or 60 series box or something.

Have you wheeled this vehicle much yet? I've taken mine one side of Australia to the other numerous times and dont really struggle with the standard steering. But others like to rock crawl etc and the demands are different - my favorite tracks are all desert tracks - dunes, occasional bit of mud, beaches sometimes, the steering demands clearly less I guess.

 

[JethroBodine]

Oh right.. I had assumed you mean electric pump into a minitruck or 60 series box or something.

Have you wheeled this vehicle much yet? I've taken mine one side of Australia to the other numerous times and dont really struggle with the standard steering. But others like to rock crawl etc and the demands are different - my favorite tracks are all desert tracks - dunes, occasional bit of mud, beaches sometimes, the steering demands clearly less I guess.

No I can't really say I've had the need for PS. That's just my backup plan.