LJ70 Mudzilla truck (1 Viewer)

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Nov 18, 2015
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G'day all,

i'm desperate to understand how my truck rear and front diff, drive shafts, pinion and ring ratio etc should be?
Mudzilla has 325/80/16 shoe, 4700 V8 2UZ engine. 5gear Manual transmission. but front and rear axles are from Bundera 1985 which has 39/8 ratio of pinion and ring / i guess/

Can somebody please en-light me?

Thanks mates

Mudzilla.JPG
 
Joined
May 21, 2006
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Rotoiti, New Zealand
Cool looking project mate!

With the torque of a 2UZ your 4.88 ratio diffs will mean the gearing won't be too bad, if you have the budget some lower ratio transfer case gears (eg Marks Adapters in Australia) will bring back the gearing closer to what you get on standard tyres.

I would be more concerned about diff & CV strength with that combination. The Bundera axles are only an 8" ring gear with relatively small CV joints. Experience has taught me, and some of my friends also, that if you have a V8 & 33"+ tyres on these axles - you will break diffs &/or CVs. We have swapped in full size Landcruiser or Nissan Patrol axles with 9" diffs. These are usually 4.11 ratio so re gearing becomes more of an issue though. I went for the Mark's gears that gave me a 8% lower hi-range & 55% lower lo-range & they are great, if a bit noisy.

I also found that with a V8 & 33's the Bundera rear suspension was not the best, the bushes on the axle would get destroyed regularly. So when I swapped in the 80 series axle & went to 36" tyres I also used the 4 link + panhard suspension from the 80 series which has been a nice improvement.

Have a look at my build thread

Cheers
Clint
 
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Joined
Nov 18, 2015
Messages
9
Location
Mongolia
Cool looking project mate!

With the torque of a 2UZ your 4.88 ratio diffs will mean the gearing won't be too bad, if you have the budget some lower ratio transfer case gears (eg Marks Adapters in Australia) will bring back the gearing closer to what you get on standard tyres.

I would be more concerned about diff & CV strength with that combination. The Bundera axles are only an 8" ring gear with relatively small CV joints. Experience has taught me, and some of my friends also, that if you have a V8 & 33"+ tyres on these axles - you will break diffs &/or CVs. We have swapped in full size Landcruiser or Nissan Patrol axles with 9" diffs. These are usually 4.11 ratio so re gearing becomes more of an issue though. I went for the Mark's gears that gave me a 8% lower hi-range & 55% lower lo-range & they are great, if a bit noisy.

I also found that with a V8 & 33's the Bundera rear suspension was not the best, the bushes on the axle would get destroyed regularly. So when I swapped in the 80 series axle & went to 36" tyres I also used the 4 link + panhard suspension from the 80 series which has been a nice improvement.

Have a look at my build thread

Cheers
Clint
Hi Clint,

Thanks for your precious advice mate. So i should find a budget for ring& pinion set with 5.29 ratio for 9" ring diff of TLC 80-s? How about Nitro gear? I have full set of OLDEMU Springs and Shocks. plus im thinking about ARB airlockers.

btw im following your project but so many stuff that i can understand :( i will come back with list of questions :)
 

Delancy

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5.29s are awfully deep for an highway driving, if that's ever intended. By the numbers (FZ/H151F/HF1A) they'd return to OE ratio with 39s, what 4.88s do for 37s.

Always appreciated 5.29s in the rocks, but the price was paid anywhere above 55mph.

While there is a low range gearset now available for the HF1A I assume is mated to the H151F, nominal gear reduction for the $2.4k Mark's commands.
 
Joined
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Hi Clint,

Thanks for your precious advice mate. So i should find a budget for ring& pinion set with 5.29 ratio for 9" ring diff of TLC 80-s? How about Nitro gear? I have full set of OLDEMU Springs and Shocks. plus im thinking about ARB airlockers.

btw im following your project but so many stuff that i can understand :( i will come back with list of questions :)

Hi Ganbi

If you drive gently you may be ok but I blew 2 back Prado diffs & one front over a few years with a std 1UZ & 33" tyres. A friend with a Hilux & a supercharged 1UZ destroyed many diffs & CV's before swapping to Nissan Patrol axles. So if you can I would definitely say build it with some stronger axles. Especially if you plan on fitting lockers! I imagine that being in Mongolia this truck is not being built just for looking cool :cool:

For my axle swap I went for a Nissan Y60 Patrol (or Safari) front axle, they are about 9" with decent CV's & a strong knuckle design, but then I wanted an offset rear diff to match the transfer case output and not have too much angle on the short SWB rear driveshaft. so the 80 series Toyota rear axle was the choice, they are the same width as the Nissan, both 4.11, 9"+ R&P, full floater too. The reason I didn't use an 80 series front axle is that they are only 8" ring gear - similar size to the old Prado although the CVs are apparently stronger.

Re-gearing the diffs is a good option too, and cheaper. But as Delancy says above you lose out if you want to go highway speed, I decided the Marks x-fer case gears were worth the money for the wider gearing spread, i use my 'cruiser for touring as well as hardcore offroad so the relaxed revs on the highway are nice, then the low range is even lower than I would get with 5.29 diffs. With my Nissan/Toyota combo I think the only lower diff gears I could get that would match in both were 4.88's & I knew 4.88's were just ok for 33" tyres offroad, the 36's would ideally need something lower.

Another thing to consider if you are fitting lockers is some cro-moly CV's & axle shafts in the front. I've got a Eaton / Harrop electric locker in the back that works well but I've way too many CV's destroyed on trucks with front lockers so I'm not going to put one in the front until I can afford the cro-moly CV's also, they seem to be really tough.

Cheers
Clint
 
Joined
Nov 18, 2015
Messages
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Hi Ganbi

If you drive gently you may be ok but I blew 2 back Prado diffs & one front over a few years with a std 1UZ & 33" tyres. A friend with a Hilux & a supercharged 1UZ destroyed many diffs & CV's before swapping to Nissan Patrol axles. So if you can I would definitely say build it with some stronger axles. Especially if you plan on fitting lockers! I imagine that being in Mongolia this truck is not being built just for looking cool :cool:

For my axle swap I went for a Nissan Y60 Patrol (or Safari) front axle, they are about 9" with decent CV's & a strong knuckle design, but then I wanted an offset rear diff to match the transfer case output and not have too much angle on the short SWB rear driveshaft. so the 80 series Toyota rear axle was the choice, they are the same width as the Nissan, both 4.11, 9"+ R&P, full floater too. The reason I didn't use an 80 series front axle is that they are only 8" ring gear - similar size to the old Prado although the CVs are apparently stronger.

Re-gearing the diffs is a good option too, and cheaper. But as Delancy says above you lose out if you want to go highway speed, I decided the Marks x-fer case gears were worth the money for the wider gearing spread, i use my 'cruiser for touring as well as hardcore offroad so the relaxed revs on the highway are nice, then the low range is even lower than I would get with 5.29 diffs. With my Nissan/Toyota combo I think the only lower diff gears I could get that would match in both were 4.88's & I knew 4.88's were just ok for 33" tyres offroad, the 36's would ideally need something lower.

Another thing to consider if you are fitting lockers is some cro-moly CV's & axle shafts in the front. I've got a Eaton / Harrop electric locker in the back that works well but I've way too many CV's destroyed on trucks with front lockers so I'm not going to put one in the front until I can afford the cro-moly CV's also, they seem to be really tough.

Cheers

Hi Clint,

how are you? summer is busy travelling around and now i back to project again. As we discussed i have 80 series rear axle with diff-lock and 4.88 ratio nitro gear set. But still not sure which axle should i put in front? Nitro gear still offer 4.88 set for 80 series front one. but you said rear is 9.5 inch and front is 8 inch. i just think both can have 4.88 ratio even they are in different sizes. Or should i put Y60's front one? What is disadvantage of 8 inch front of TLC 80 series?

Thanks mate
 
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Hi Clint,

how are you? summer is busy travelling around and now i back to project again. As we discussed i have 80 series rear axle with diff-lock and 4.88 ratio nitro gear set. But still not sure which axle should i put in front? Nitro gear still offer 4.88 set for 80 series front one. but you said rear is 9.5 inch and front is 8 inch. i just think both can have 4.88 ratio even they are in different sizes. Or should i put Y60's front one? What is disadvantage of 8 inch front of TLC 80 series?

Thanks mate
 
Joined
May 21, 2006
Messages
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Rotoiti, New Zealand
Hi Ganbi, All good here, was out enjoying the snow in my Landcruiser last week!

You sure can have a 4.88 ratio ring & pinion for both the 9.5" dia rear & the 8" dia front diffs on an 80 series Toyota.

The main disadvantage of the 80 series front axle is the strength of the 8" ring & pinion. This is a known weak point when running big tyres, I have heard of some people breaking them. The Y60 9" however hardly ever breaks.

Another issue with the 80 series (& other Toyotas) is the knuckle steering arms are part of the kingpin caps & they bolt on to the knuckle, under heavy use these can work loose & break studs so people install stronger studs & they need to be checked regularly. The Nissan has the arms cast into the knuckle which seems to be stronger.

Over here Y60 & 80 series parts are both easily available, Y60 stuff is often cheaper as they have been around a long time, so for me that all added up to using the Y60 Nissan front axle & it's been good so far. Various friends are using Y60 axles in some crazy winch challenge & offroad race trucks & I think the only guys that have ever broken a R&P have a 500hp supercharged VH60 trophy truck, & IIRC they've only had one problem in about 8 years of hard racing.

Cheers
Clint
 
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Hi Ganbi, All good here, was out enjoying the snow in my Landcruiser last week!

You sure can have a 4.88 ratio ring & pinion for both the 9.5" dia rear & the 8" dia front diffs on an 80 series Toyota.

The main disadvantage of the 80 series front axle is the strength of the 8" ring & pinion. This is a known weak point when running big tyres, I have heard of some people breaking them. The Y60 9" however hardly ever breaks.

Another issue with the 80 series (& other Toyotas) is the knuckle steering arms are part of the kingpin caps & they bolt on to the knuckle, under heavy use these can work loose & break studs so people install stronger studs & they need to be checked regularly. The Nissan has the arms cast into the knuckle which seems to be stronger.

Over here Y60 & 80 series parts are both easily available, Y60 stuff is often cheaper as they have been around a long time, so for me that all added up to using the Y60 Nissan front axle & it's been good so far. Various friends are using Y60 axles in some crazy winch challenge & offroad race trucks & I think the only guys that have ever broken a R&P have a 500hp supercharged VH60 trophy truck, & IIRC they've only had one problem in about 8 years of hard racing.

Cheers
Clint


I'm still leaning about my new HZJ73, but I have experience with 80 series fronts with the 8" ring gear (similar to what is in my new truck) and the 8" front is a tough set up. The high pinion pretty much makes up for the ring gear size and the outers are much stronger. You only start running into problems when you run lower diff gears because the teeth get smaller.

I'm getting around this in my truck by keeping the diffs stock and doing the Advance Adapters 4:1 gear set with the 10% underdrive with 35" tires. Should be pretty much bulletproof and push the truck in 35s around with no issues.
 
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Hi Clint,

did some search on Y60 front and 80's rear but looks ring and pinion ratio is different. Therefore finally decided to have a nitro gear front, rear whole set of 5.29 and CV for current 8" Bundera axle :) let's just try to do so and if something bad happens go for further solutions :)

will keep you updated mate

Thanks a lot
 
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I'm still leaning about my new HZJ73, but I have experience with 80 series fronts with the 8" ring gear (similar to what is in my new truck) and the 8" front is a tough set up. The high pinion pretty much makes up for the ring gear size and the outers are much stronger. You only start running into problems when you run lower diff gears because the teeth get smaller.

I'm getting around this in my truck by keeping the diffs stock and doing the Advance Adapters 4:1 gear set with the 10% underdrive with 35" tires. Should be pretty much bulletproof and push the truck in 35s around with no issues.
Hi mate,

now im installin 5.29 ration Nitro gear set with CV joints. So do i still need to do something lower in my transmission? engine is 2UZ-FE and transmission is H151F 5 gear manual.

Thanks
 
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Hi mate,

now im installin 5.29 ration Nitro gear set with CV joints. So do i still need to do something lower in my transmission? engine is 2UZ-FE and transmission is H151F 5 gear manual.

Thanks

No, you don't need to do anything else for drive ability, that thing is going to be a rocket with a V8 and 5.29s. The set I'm talking about is from Advance Adapters here in the States, they have a set that drops into a split case that gives you a 4:1 low range with a 10% gear reduction in high range. With 5.29s and a 10% reduction you could barely do highway speeds. I know Marks in Australia makes some really nice t case gear sets that are a little less invasive of an install than the AA gears (which require that you machine the case), just with a little less gear reduction. If you want to look at crawl ratio, you should check em out.
 
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Hi Clint,

did some search on Y60 front and 80's rear but looks ring and pinion ratio is different. Therefore finally decided to have a nitro gear front, rear whole set of 5.29 and CV for current 8" Bundera axle :) let's just try to do so and if something bad happens go for further solutions :)

will keep you updated mate

Thanks a lot

Some Y60 were different - the 2.8 diesel engined 'Spirit' model - had 4.6 diff gears, 4.2 petrol manuals had 3.9 but the common 4.2 diesels are all 4.11 AFAIK. 80 series are 4.10 & when you work out the difference it isn't any more than you might get having slightly more worn tyres on one axle. My 80 series rear & Y60 front diffs are definitely close enough cos I counted the teeth on both!

It'll be interesting to see how those Nitro gears hold up. Apparently setup is crucial to get the most strength out of the Toyota 8" so if you aren't a diff expert do a bit of googling to find some tips. Don't forget to post some more pics!

Cheers
Clint
 
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No, you don't need to do anything else for drive ability, that thing is going to be a rocket with a V8 and 5.29s. The set I'm talking about is from Advance Adapters here in the States, they have a set that drops into a split case that gives you a 4:1 low range with a 10% gear reduction in high range. With 5.29s and a 10% reduction you could barely do highway speeds. I know Marks in Australia makes some really nice t case gear sets that are a little less invasive of an install than the AA gears (which require that you machine the case), just with a little less gear reduction. If you want to look at crawl ratio, you should check em out.
Hi buddy, oh i see. at the moment i rather stick with 5.29 and we will see. thanks and i will keep you informed
 

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