Diff Ratio Q (4 Viewers)

[gotoy]

The LJ70 originally had a 2L engine and 4.88 dif ratio.

I later converted the LJ70 to a 1kz using a KZJ78 halfcut or clip.

The ratio was kept at 4.88.

I am using 33" tyres for everyday use and 35" for hard offroad.

Is the 4.88 ratio correct? Or should the ratio be 4.56?

 

[gotoy]

From the chart I may be better off with 4.56.

Differential Gear Ratio Chart - Tire Size to Gear Ratio

 

[gotoy]

The diff ratio for a kjz78 is 4.1 if not mistaken?

 

[gotoy]

Not a simple case of changing the ring gear and pinion. The 4.56 wont fit into a 4.88 units. Need to change both the pumpkins!!

 

[Malahki]

I am running 4.56's with 35's on my BJ74 (13BT) and it runs at 120km/h at 3000rpm on the highway but could use lower gears in low range.

 

[gotoy]

I am running 4.56's with 35's on my BJ74 (13BT) and it runs at 120km/h at 3000rpm on the highway but could use lower gears in low range.

Thats seems a good rpm at 120, min is 3300 on 4.88.

For lower range gears you could consider lower gearing on the transfer case; ie marlincrawler.

 

[Josie'sLandCruiser]

Hi All:

MarlinCrawler gear sets fit the HiLux t-case, not the Land Cruiser t-case.

A buddy of mine has a '89 LJ73. It came with the 2LT-E and 4.88 ratio diff gears. Once the 2LT-E died he swapped-in a 22R-E and hated the 4.88 diffs for the size of tires he is running (31X10.5R15)

He switch to 4.10 ratio diff gears and is much happier.

Regards,

Alan

 

[PhrogsPhorever]

Going from the 2LT to the 1KZTE would make going to a 4.10 diff not too bad.

You make up the power with the new motor, and gain great road manners with the 4.10 gears

Did you stick with the R150F tranny?

 

[Malahki]

Hi All:

MarlinCrawler gear sets fit the HiLux t-case, not the Land Cruiser t-case.

Yeah but Marlin has the toybox for the split cases and Marks 4wd has the t-case gear sets. $$$$

Speaking of the Marks gears, Gotoy you could get the set with the 2.82 low range and the .92 overdrive. which would put you damn close to having 4.56's.
4.88x.92=4.48

 

[gotoy]

Going from the 2LT to the 1KZTE would make going to a 4.10 diff not too bad.

You make up the power with the new motor, and gain great road manners with the 4.10 gears

Did you stick with the R150F tranny?

R151F.

 

[gotoy]

Yeah but Marlin has the toybox for the split cases and Marks 4wd has the t-case gear sets. $$$$

Speaking of the Marks gears, Gotoy you could get the set with the 2.82 low range and the .92 overdrive. which would put you **** close to having 4.56's.
4.88x.92=4.48

I have explored that route some time ago, not to get 4.56, more for the low range and overdrive.

I never had a confirmation from Marlin that they would fit the R151F box and transfer case. You probably H55 box behind the 13bt.

Do you know if they can be used? My axles are the 8" types.

Have already located a set of 4.56's for the axles. So the plan is to put them in and see how they peform. If ok I'll sell off the 4.88's.

 

[crushers]

i am running the 4.88s with 33s and the R151 behind the PZ. it is a love / hate relationship. off road the 4.88s and 36" tractor tires are a perfect match and i wouldn't change them out. on the highway with 33s i find the RPM hard to deal with when over 110 k/h.
if your speed limit (or driving style) is between 80 and 100 then i would leave them. if your cruising speed is over 100 then i would change them out.
i am leaving mine in. it wouldn't be worth the effort or expense to just drop to 4.56. if i was going to change them out it would be to 4.11 with a swap to the R141.

 

[gotoy]

I am running 35" tyres, but usually just use 33" MT.

I will try the 4.56's for a while and see how. If need be just change back to 4.88. No hassle to change.