FJ40 Diff

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JonFJ1969

JonFJ1969

Joined
Mar 8, 2012
Threads
6
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Location
Newark
Hi, i own a 1973 FJ40 with a Chevy 305Ci V8, marks adapter fitted to a standard 4 speed transmission with a PTO driven winch. I have been advised my front diff is on the way out as it clunks when it gets put into gear etc.. over here in the UK there isn't the abundance of spare parts for the 40 series and my question is, is it possible to fit the diff off a another series, 70 series, hilux etc because there are plenty of those available, i could look to buy another FJ40 diff over here but chances are it will be in a similar condition to mine. any help much appreciated,
or would you suggest an overhaul?, the truck doesn't get used much and i am on a tight budget, many thanks Jon
 
60 or early 70 series should be a straight swap.
 
The rear locking diff from a FJ80 will fit as well, takes a little clearancing to fit the locking mechanism. I wouuld think the non locking would fit too. The ratio should be 4.10 which is close enough to 4.11 hopefully under your truck.

Will have to do some driveline mods or pinion flange so it will bolt up.
 
HI, sorry for sounding a bit dumb, is mine a 4.11? is there a way to tell, is it a question of counting teeth or is it marked on it somewhere? also assuming i buy the replacement diff from a breaker apart from his word, how would i know the ratio?
thanks Jon
 
Bret said:
The rear locking diff from a FJ80 will fit as well, takes a little clearancing to fit the locking mechanism. I wouuld think the non locking would fit too. The ratio should be 4.10 which is close enough to 4.11 hopefully under your truck.

Will have to do some driveline mods or pinion flange so it will bolt up.
Click to expand...

Non-locking 80 series diff will also work. Ratio of the rear 80 series is 4.11. If the diff is pulled from a FF axle a c-clip retaining block will have to be swapped in, assuming the diff is going into a SF FJ40 axle.
 
JonFJ1969 said:
HI, sorry for sounding a bit dumb, is mine a 4.11? is there a way to tell, is it a question of counting teeth or is it marked on it somewhere? also assuming i buy the replacement diff from a breaker apart from his word, how would i know the ratio?
thanks Jon
Click to expand...
Count the teeth it is the safest way to make sure its a 4.11 not a 4.1
 
Found a diff from a 70 series, but the chassis number info i gave to toyota UK came back as 39;8, 4.875, assuming mine is a 4.11 this wont wont will it? is it worth considering reconditioning mine with new parts? cheers Jon
 
I don't think that Toyota made a 4.875. Someone needs to physically count teeth or rotations to be sure.

An fzj80 locker will interfere with the oil pan in a 2f with no lift. You need to be sure with your V8.

The difference in ratios between a 4.10 and a 4.11 is 0.25%, which is not significant in any way. They will match up fine. Difference in tire wear or air pressure front to rear could easily be this much.

I am very surprised that your rig has spent enough time in 4wd to wear out the diff. I would disassemble it and figure out what is really going on with it.
 
just checked the parts catalog it does show that gear ratio for the 70 series over there .

check the 70 series after 1990 they only seemed to use three differnt gear sets . 4:11,4;10,and 4:30 the earlier ones seem to have .3:73, 4:30,4:87

wow i never new toyota had so many gear options .




JonFJ1969 said:
Found a diff from a 70 series, but the chassis number info i gave to toyota UK came back as 39;8, 4.875, assuming mine is a 4.11 this wont wont will it? is it worth considering reconditioning mine with new parts? cheers Jon
Click to expand...
 
Hi All:

Jon1969, I would guess that 4.875 ratio diff is from a LJ/RJ70 light-duty Land Cruiser (which uses the same 8 inch ring gear diffs from the HiLux.)

The B/F/HJ40/45/55/60/70/75 Series land Cruisers have a 8.75 inch ring gear differential.

Regards,

Alan


JonFJ1969 said:
Found a diff from a 70 series, but the chassis number info i gave to toyota UK came back as 39;8, 4.875, assuming mine is a 4.11 this wont wont will it? is it worth considering reconditioning mine with new parts? cheers Jon
Click to expand...
 
Hi All:

I would check how tight the u-joints are on the front drive shaft (prop shaft) before pulling the front differential.

If the u-joints seem alright, check the pre-load on the pinion gear of the front diff.

Regards,

Alan


JonFJ1969 said:
Hi, i own a 1973 FJ40 with a Chevy 305Ci V8, marks adapter fitted to a standard 4 speed transmission with a PTO driven winch. I have been advised my front diff is on the way out as it clunks when it gets put into gear etc.. over here in the UK there isn't the abundance of spare parts for the 40 series and my question is, is it possible to fit the diff off a another series, 70 series, hilux etc because there are plenty of those available, i could look to buy another FJ40 diff over here but chances are it will be in a similar condition to mine. any help much appreciated,
or would you suggest an overhaul?, the truck doesn't get used much and i am on a tight budget, many thanks Jon
Click to expand...
 
i checked the catalog again and you right Alan . the only gears avaialble that would fit the 40 are 3.73 and 4.11 from the 70 series. from the BJ,HJ,and FJ 70 models . not the RJ and the LJ70

good catch . :cheers:
 
Josie'sLandCruiser said:
Hi All:

I would check how tight the u-joints are on the front drive shaft (prop shaft) before pulling the front differential.

If the u-joints seem alright, check the pre-load on the pinion gear of the front diff.

Regards,

Alan
Click to expand...

^^ Exactly

A "clunk" is a little too non-specific to start shopping for new gears.
 
Txtlw
 
I am very surprised that your rig has spent enough time in 4wd to wear out the diff. I would disassemble it and figure out what is really going on with it.[/QUOTE]


I would check how tight the u-joints are on the front drive shaft (prop shaft) before pulling the front differential.

If the u-joints seem alright, check the pre-load on the pinion gear of the front diff



Pin_Head said:
^^ Exactly

A "clunk" is a little too non-specific to start shopping for new gears.
Click to expand...


What they said.......
 
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