80 series rear axel on a 40 series

[rideglobally]

i know this has been done before, what has been the experience on an expedition vehicle? what modification is needed? will the rear differential line up with the transmission so that the axel will be straight? any issue with vibrations? i have search this forum can not find any ... thanks :smiley_drive:

 

[Aggie]

ih8mud.com will be your biggest asset here...

 

[AndrewP]

Some fab work will be involved, and you'll need to strip all of the bracketry, but I don't see the advantage for an "Expo" truck. For true expo use you want to be as close to stock as possible.

An 80 series axle will stick out pretty far from the wheel wells, which will throw more dirt/mud/rocks on your truck, and may be illegal.

If you're really building an offroader/rockcrawler the extra width is an advantage, but then what will you do about the front end?

I'm running FJ60 axles under my FJ40, and that extra width is a good thing-but it's only 3 inches or so. FJ60 axles would be much easier that 80 series axles. Do you plan a spring over as well?

Maybe tell us what you plan to do with the truck and we can make more specific recs.

Kind of get the FJ60 width idea here:

 

[rideglobally]

80 series axel on a 40 series

ih8mud.com will be your biggest asset here...

i am on ih8mud and it is very helpful, however, advise that i have gotten have no direct experience with the conversion, also i have seen link who have done conversions for trails or rock crawler cruisers. :smiley_drive:

Some fab work will be involved, and you'll need to strip all of the bracketry, but I don't see the advantage for an "Expo" truck. For true expo use you want to be as close to stock as possible.

An 80 series axle will stick out pretty far from the wheel wells, which will throw more dirt/mud/rocks on your truck, and may be illegal.

If you're really building an offroader/rockcrawler the extra width is an advantage, but then what will you do about the front end?

I'm running FJ60 axles under my FJ40, and that extra width is a good thing-but it's only 3 inches or so. FJ60 axles would be much easier that 80 series axles. Do you plan a spring over as well?

Maybe tell us what you plan to do with the truck and we can make more specific recs.

Kind of get the FJ60 width idea here:

http://forum.ih8mud.com/attachment.php?[/QUOTE]

the width of the "bed" on my cruiser is 80 inches wide and 19 feet long bumper to bumper that is why i want to
widen my track. on the front i will keep it stock but use a back space wheels to compensate for the wide in the rear.

i will keep the leaf springs, no i do not plan a spring over.

yes i understand i need to strip out the bracketry. i also plan to use a full floating axel between 1993 to 1997.

do you know if the differential will line up with the transmission? this is my biggest concern. if it does not how do i prevent possible vibration for the the drive shaft not being aligned.

picture of my cruiser below, there has been updates since this picture. :smiley_drive:

 

[DBS311]

I can't give you exact measurments, but the 80's center section appears to be more centered when compared to the 40 and 60 series. Again, I have no specs, this is just from looking behind both vehicles.

Why not just use a 60 series FF? It already has the spring perches and will save you time and $$$ that will be needed to get an 80 series rear to fit/work. BTW, what ratio are you running? The 80's from '93-'97 came with 4.10's (IIRC).

 

[rideglobally]

I can't give you exact measurments, but the 80's center section appears to be more centered when compared to the 40 and 60 series. Again, I have no specs, this is just from looking behind both vehicles.

Why not just use a 60 series FF? It already has the spring perches and will save you time and $$$ that will be needed to get an 80 series rear to fit/work. BTW, what ratio are you running? The 80's from '93-'97 came with 4.10's (IIRC).

the 60 series is not wide enough, i need the wide. on the ratio. i have not decided, what do you think of the 4.10 on a 12ht engine with a 5 speed transmission 35 inch diameter wheels. :smiley_drive:

 

[cruiseroutfit]

The 80 Series is in deed "more centered" than the 40/60 axles. FWIW even the 60 axle in a 40/55 will leave a slight jog in the rear driveline as only the long side of the axle changes between the two, pushing the pinion ~1.5" to the passenger side. They didn't need to wide them proportionally as the split-case in the 60 has a slightly wider input to output stance.

Your biggest hurdle is going to be the jog in the drivelines and what could be potentially too much width (8" wider than your 40 axle) at ~63". Even with a stockish 15x8 - 3.5BS you'll be sitting ~75" wide at the rims? Too wide? Good?

 

[dieselcruiserhead]

I have done it, about to get on a plane but I'll post up in a sec. It is a nice conversion, but very wide. I am doing it under my FJ55 (FJ40 width) currently using high backspaced FJ Cruiser steel wheels. I do not think it compromises reliability as you basically have a FZJ axle, probably more popular today than a 40 series. And generally stronger and more reliable...

 

[rideglobally]

80 series axel on a 40 series

I have done it, about to get on a plane but I'll post up in a sec. It is a nice conversion, but very wide. I am doing it under my FJ55 (FJ40 width) currently using high backspaced FJ Cruiser steel wheels. I do not think it compromises reliability as you basically have a FZJ axle, probably more popular today than a 40 series. And generally stronger and more reliable...

great cannot wait to read you post. i desperately need to widen my track in my case the 80 series axel are not gonna stick out. the total wide of my 40 series in the rear is 80 inches (see attached picture above) and 19 feet long bumper to bumper.

my main concern is this; if the drive shaft is "jog" to one side, i assume this to mean that the drive shaft will not be alight from the rear differential to the transmission, will this cause a vibration at freeway speed?

looking forward to hearing about your experience...... thanks :smiley_drive:

 

[a.mus.ed]

The only thing that bugs me about what you've said - and I may be incorrect, so please correct me - is that you would be running different backspaced rims front to back. My OCD aside, this seems that it would be a problem for spares and tire rotation.

 

[dieselcruiserhead]

I believe sky manufacturing is still around, they make a spacer kit that lets you run IFS mini truck hubs up front and this counteracts the 80 series axle width or at least does with a 60 series axle. This is the easiest method.

I've done it twice, once on a 40 and once on an 60, in both cases they were fine but needed a CV joint in the rear shaft to counteract vibration that arose. We also pointed the diff at the t-case for greater ground clearance and a CV is usually required when you do this as well and both were spring over axle applications as well. On my 55 I'm running a t case with a centered rear output with the 80 axle and largely because it turned out well on these other apps I didn't mind the slightly crooked approach to this one...

If it were me I would run them front and rear, and make an imitation 80 series OEM suspension up front with coils, leafs in the rear, using parts primarily from Ballistic fab. This is the same approach I'm about to take on my mini truck using a FJ62 axle and 80 series radius arms and parts from Ballistic Fabrication. If you build it smart and beefy enough it is just fine for "expedition" type use...

Here is a photo of the 80 series under my 55 (using a FZJ80 frame with stock suspension). The 55 width is about the same as a 40 I figure, they use the same axle... This is with high-backspaced random wheels I had lying around. I have the tires and FJ Cruiser wheels, I should mount them up to see how they look. I should loose about an inch in width (easily) once they are on there, versus these pics...

 

[Pskhaat]

Factory designers often place the track width of the front wider than the rear, unless you put 80 series axles under both f&r, you may incur additional understeer and not tracking as well on the trail/snow/corner? My understanding is that a narrower rear track increases rear body roll out of a corner which actually increases rear outside traction at the end of a turn.

 

[rideglobally]

I believe sky manufacturing is still around, they make a spacer kit that lets you run IFS mini truck hubs up front and this counteracts the 80 series axle width or at least does with a 60 series axle. This is the easiest method.

I've done it twice, once on a 40 and once on an 60, in both cases they were fine but needed a CV joint in the rear shaft to counteract vibration that arose. We also pointed the diff at the t-case for greater ground clearance and a CV is usually required when you do this as well and both were spring over axle applications as well. On my 55 I'm running a t case with a centered rear output with the 80 axle and largely because it turned out well on these other apps I didn't mind the slightly crooked approach to this one...

If it were me I would run them front and rear, and make an imitation 80 series OEM suspension up front with coils, leafs in the rear, using parts primarily from Ballistic fab. This is the same approach I'm about to take on my mini truck using a FJ62 axle and 80 series radius arms and parts from Ballistic Fabrication. If you build it smart and beefy enough it is just fine for "expedition" type use...

Here is a photo of the 80 series under my 55 (using a FZJ80 frame with stock suspension). The 55 width is about the same as a 40 I figure, they use the same axle... This is with high-backspaced random wheels I had lying around. I have the tires and FJ Cruiser wheels, I should mount them up to see how they look. I should loose about an inch in width (easily) once they are on there, versus these pics...

thanks
1. i have heard about the IFS spacer kit and that is an option for the front, i plan to look more into that option later. i think that is a real option.

2. on the rear axel i have a couple of question. a) what kind of CV joint did you use to counteract the vibration? did you use a double Cardan CV joint?
b) how many inches will the transmission will be miss align with the rear differential? also my conversion will not be spring over axel, my cruiser has only been raised to 3 inches so it is not that much.

i would like to run 80 series on the front but that maybe for later, right now i am just focus on getting the rear done.

the pictures are great, i would appreciate picture from under the vehicle if you have them.

thanks again :Wow1:

 

[soenke]

Hey Amado,

just read across this, so sorry if I missed a point.

I would go with the 60 axels and if the width isn´t sufficient add steal spacers front and rear. And I would use both axles in front and rear and not mess around with aftermarket kits. Nice would be to have two strong diffs and not a high pinion in front as the 80 provides. Biggest advantage would be to stick to Toyota parts, making replacement on tour easyer. Keep it simple and stock as much as possible!
The 60 axle-conversion build has been done by many, for example by Marcus www.offroad-schmiede.com or the dutch guy with the perfeckt HJ45visiting your thread on mud...

Greetings Sönke

 

[rideglobally]

Hey Amado,

just read across this, so sorry if I missed a point.

I would go with the 60 axels and if the width isn´t sufficient add steal spacers front and rear. And I would use both axles in front and rear and not mess around with aftermarket kits. Nice would be to have two strong diffs and not a high pinion in front as the 80 provides. Biggest advantage would be to stick to Toyota parts, making replacement on tour easyer. Keep it simple and stock as much as possible!
The 60 axle-conversion build has been done by many, for example by Marcus www.offroad-schmiede.com or the dutch guy with the perfeckt HJ45visiting your thread on mud...

Greetings Sönke

thanks Sonke, my read bed is 80" wide. i think a 80 series would be great to achieve the with that i need. i did some measuring to figure out the alignment of the drive shaft to the rear axel differential here is what i found. the shaft will shift to the left by about 3 1/2 inches, so there will be an angle. my current drive shaft is 44 inches long from the rear diffrential to the cross over bearing (see picture) then there is a a short 1 foot drive shaft that connect from the cross over bearing to the transmission. i am thinking of removing the cross over bearing and connect the drive shaft from the rear diffrential to the transmission directly, this will lengthen my drive shaft to 5 foot. i am considering this to lessen the angle of the drive shaft.

how long is your drive shaft?