h55f transmission in a '78 BJ40

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

B

Big Pat

10 Year 15 Year
Joined
Nov 14, 2007
Threads
3
Messages
15
Location
Melbourne, Australia
G'day!

I'm new to the forum. I've had my largely untouched 1978 BJ40 for about 5 years now, and am wanting to replace the existing 4 spd gearbox for a 5 spd. Figure it'd be nice in terms of fuel comsuption and engine noise / wear on the highway - especially before I spend any money on engine reconditioning. I was thinking a h55f? Has anyone got any ideas whats invovled with this? Is it a simple swap over type situation or is there a lot of modifcation required? Im not too clued up in this area, so even simple tips and suggestions would be highly welcome!

Cheers!

Pat
 
Hi All:

G'day Pat! Welcome to MUD! :cheers:

Make use of the "search" function and you will find some info. There is a recent thread by "Poser" about swapping a H55F into a '79(?) FJ40. Although not exactly the same rig as yours, still helpful information.

Off the top of my head, things that will be changed in this conversion:

* drive shafts - front will need to be longer, rear shorter.

* the H55F uses a transmission mount/crossmember that is different than the bellhousing mounts on a '78.

* clutch parts different

* different transfer case (you have the old "one-piece" type, while the H55F uses the later "split" type t-case)

* parking brake - on your '78 it is on the transfer case; some 'split t-cases came with a p-brake assembly, some did not.

So, certainly possible, but not a straight bolt-in affair.

Good luck!

Alan
 
Pat, you need to post more details about your truck... being your using the "G'day" thing I assume your in or from OZ? ...if so and your truck is also, there's no way to say for sure what you have there......
 
Thanks for the tips Alan, and stearing me towards that thread! Lots of inspiration there.

The Oz assumption was correct! As for some more specs...I've got the 3L B engine and a h41 transmission. Apparently not so common in some parts as the h42. Not sure about the transfer case though? Will that be stamped somewhere?

Cheers
 
5 Speed to 3B diesel...

G'day Pat,

I've found a few interesting write ups about it.. enough to be hunting for a suitable gearbox myself.

http://users.bigpond.net.au/blmiller/4WDing/LandCruiser/tlc-gbox.html

Think this one is for a 2F but the guy is in Perth...

Might see if I can "borrow" one from a wrecker whilst I've got the body off the BJ42 and have a play.. see if it fits..

You could always contact Marks 4WD Adaptors. Bet my left nut someone there would be able to point you in the right direction..

Cheers
Craig
 
Hi All:

Pat, I should have mentioned, the H55F you need for use in your BJ40 will have to have come from behind another "B" Series engine (i.e. 2B, 3B, 13B-T, etc.) The "B" diesels used a fine spline input shaft on the transmissions, while the "F" and "H" Series engines used a coarse (ten) spline input shaft.

Regards,

Alan
 
Cheers guys!

Just noticed the input shaft thing myself. The clutch is also meant to be compatible provided its from another B engine. Same with it being possible to mount on the bellhousing. Im hoping the driveshafts from a 5 spd BJ42 will also fit my BJ40. Still researching this.

Its guess its more a matter of the park brake. Ive seen "split transfer case parking brake conversions" on offer and guess these would be the least fuss. Would there be any advantage in having a diff handbrake? Marks 4wd adaptors stock these conversion kits. Might have a chat with them too.... Hopefully, Craig, it wont result in you losing any body parts!!
 
Lost Parts

Hi Pat,

No mate, go for your life. My BJ has handbrakes to the rear wheels already.. but keep me posted what you find out. I was under the assumption that provided the box was from a diesel (input shaft) it was a pretty straight forward replacement (tailshafts asside).
I'll keep asking questions too.

Cheers
Craig
 
Just ordered the gearbox! It'll be interesting to see how it'll fit!!! The whole thing is meant to be a little longer (~100mm) at the rear, and theres a crossmember on the chassis probably about ~101mm behind it! I dont know how different the bj40 chassis is from a bj42?

Oh well! Ill find out shortly enough.
 
I've always moved the park brake to the rear wheels on 79/'80 conversions, being that cross member is gonna interfere and the fuel tank doesn't allow moving it rearward ..... anyway, its been more cost efective for me.....
 
Sorry Grant, wasnt quite sure about the fuel tank getting in the way.

Also, did you do the same sort of conversion on yours? Handbrake adaptor aside, did that crossmember interfere with installing the gearbox?

Does the following handbrake adaptor end up adding much bulk / length in the wrong spot?
http://www.marks4wd.com/products/split-t-case/lc-split-t-case-hand-brake.htm

I can get the whole rear wheel handbrake assembly from the bj42 where the h55f came from, but it has a floor mounted handbrake lever as opposed to my dash mounted one. This would mean cutting holes in the floor. I was told I could remove the crossmember, and drive as is (onraod), but should eventually attach another homemade one (from RHS) a further back to stop the chassis twisitng. Is this a bad idea?
 
The parking brake adds about 3.5 inches to the length of the transfer case. There is a picture somewhere on mud showing hte 4 and 5 next to each other.

I have a rebuilt H55F with the split transfer case and parking brake. I was thinking of just putting in rear disk and moving the paking brake there. Downey makes a cable to splice the two systems together.
 
I saw that thread just yesterday and started to think I should seriously consider a crossmember support! It’s nice to see the newly added pictures though. Thanks!

As I understand it, my BJ40 has the exact same chassis as the BJ42 where my h55f is coming from. Is this true? This being the case, does anyone know if I'd be able to use a BJ42 crossmember support? Will one off a 60 series diesel be more appropriate, or is this simply another alternative for sourcing a suitable part?

Also, I’ve been researching the “transfer case park brake conversion” alternatives. I know the Marks 4wd adaptors version will require shortening the rear driveshaft by 30 mm. My understanding is that the MAF kit will not require this. Could anyone confirm this?

I’ve been getting my crossmembers muddled as well. There’s one to support the h55f gearbox (mentioned above), which I don’t have, but should add. The other relevant crossmember is the pre-existing one on the chassis, yeah? Do they have different names to distinguish them? Mine looks different to the one in the thread mentioned above (watrob’s post). This one is straight and raised the whole way across. Mine just has a kink allowing the rear driveshaft to pass under it. Is it this one which will interfere with the installation of the h55f? If the h55f were fitted without the handbrake adaptor would it clear the chassis crossmember? Or is the problem more the extra gear in the h55f makes the unit itself too long? Am I completely off the mark? Sorry for the stupid questions. Perhaps it’s an indication that I shouldn’t be doing all my research at work where its being continually interrupted!!
 
Hi All:

Pat, if Aussie 40 Series are like North American 40 Series, there was a body tub change in 1979, and both gearbox and suspension changes in mid-1980.

On a 1978 or older 40 Series the transmission is supported by mounts at the engine bellhousing. The 1979 and newer 40 Series used a transmission mount instead, that mounts underneath the transmission (like on the 60 Series.)

So, though you could certainly use the bellhousing mounts with the H55F I would think that the later transmission mount is a much better idea.

Your '78 BJ40 probably has a tube cross member permanently mounted between the frame rails just behind the transfer case. This may, or may not, need to be removed/modified.

The '79 and newer 40 Series had the parking brake on the rear axle assembly. I think that it is easier to simply use a late model 40 Series rear axle assembly with factory parking brake then to try to fit the t-case p-brake into your drive train. What I mean here that without the t-case mounted p-brake the H55F and t-case *might* clear that tube cross member.

Good luck with the conversion - I hope to be able to do a similar project someday in the future! :D

Regards,

Alan


--------------------------------------------------------------------------
Big Pat said:
[COLOR
=white]

I saw that thread just yesterday and started to think I should seriously consider a crossmember support! It’s nice to see the newly added pictures though. Thanks!

As I understand it, my BJ40 has the exact same chassis as the BJ42 where my h55f is coming from. Is this true? This being the case, does anyone know if I'd be able to use a BJ42 crossmember support? Will one off a 60 series diesel be more appropriate, or is this simply another alternative for sourcing a suitable part?

Also, I’ve been researching the “transfer case park brake conversion” alternatives. I know the Marks 4wd adaptors version will require shortening the rear driveshaft by 30 mm. My understanding is that the MAF kit will not require this. Could anyone confirm this?

I’ve been getting my crossmembers muddled as well. There’s one to support the h55f gearbox (mentioned above), which I don’t have, but should add. The other relevant crossmember is the pre-existing one on the chassis, yeah? Do they have different names to distinguish them? Mine looks different to the one in the thread mentioned above (watrob’s post). This one is straight and raised the whole way across. Mine just has a kink allowing the rear driveshaft to pass under it. Is it this one which will interfere with the installation of the h55f? If the h55f were fitted without the handbrake adaptor would it clear the chassis crossmember? Or is the problem more the extra gear in the h55f makes the unit itself too long? Am I completely off the mark? Sorry for the stupid questions. Perhaps it’s an indication that I shouldn’t be doing all my research at work where its being continually interrupted!!
[/COLOR]
Click to expand...
 
I'm going measure up the distance between the frame rails on my '78 BJ40. The seller of h55f from the '83 BJ42 has offered to do the same. If they’re the same I'll buy that transmission mount cross member. It’s a little tricky to know exactly where to measure from, because the rails aren’t parallel in that section of the frame, but it should give me an indication. Despite all the other changes over the years (body tub, gearbox, suspension etc.) with any luck the actual frames on both vehicles will not be different. My landcruiser manual (1980) at least shows the BJ (FJ) 40 and 42's having the same frame as each other, and also the same tube cross member (with that kink in there) which I have in my '78. Someone with an '80+ 40/42 series could confirm this maybe? Hopefully the transmission sits at the same height in both years as well. I guess I can use spacers to alter the position if it is higher or lower. I am assuming there are bolt holes on the underside of the h55f?

Separating the handbrake from the drive-train, using the BJ42’s rear diff handbrake set-up, is looking more and more like the way to go. Taking into account shipping costs to Australia, the MAF adaptor will end being very expensive. The Marks adaptor obviously requires shortening the rear drive shaft. In either case the tube cross member may or may not allow it to bolt straight on like I want it to!

It would’ve been nice to install everything at once, but until I have the h55f in front of me, it’s too hard to say what will work. I might just do the transmission swap first, and leave the hand brake until later. I'll just have to park in gear and carry some house bricks wherever I go! I wonder whether simply using a longer handbrake cable would allow me to retain my dash-mounted handbrake lever and use everything else on the BJ42's rear diff hand braking system? That is everything except the floor-mounted lever which requires holes being made. Time will tell!

I reckon, it'll be two weeks until I get to that stage. Of course, any more suggestions in the meantime are most welcome. They've all been really helpful so far. Much appreciated! I'll take lots of photos and notes too, for all those who are keen to attempt the same thing!
 
You must log in or register to reply here.

Share this page

Back
Top Bottom