LJ70 Build Thread!

[adrianr]

Hot diff. Are you 100% certain the ratios same front and rear?

 

[Maverick]

When i got back i checked everything over and one thing i did notice, is that the diff was too hot to touch. Is this normal?

Stupid I know Ben, but you DID put oil in the Diff and Axle??

 

[Ben]

If anyones going for a drive later, maybe they could see how hot there axle is afterwards?

Hot diff. Are you 100% certain the ratios same front and rear?

Yes, and it wouldnt make any difference if they wernt, because it was in 2wd on my test drive.

When i got back i checked everything over and one thing i did notice, is that the diff was too hot to touch. Is this normal?

Stupid I know Ben, but you DID put oil in the Diff and Axle??

Yes Brett, got oil in mate.

 

[Maverick]

I've never touched my Diff after using it ... How was the Front Diff, was that HOT too?

 

[adrianr]

Did 100 motorway miles the other month then changed oils. Both diff just nice and warm, not hot

 

[jeepmadmike]

Your diff sounds on the hot side for a short journey

But they might all be like that

When I changed the oils on my truck I did drive it to warm it all up and it I don't remember them being that hot...?

I have noticed that on wet days the diff is usually dry a short while after driving.....

 

[Ben]

Brett was in 2wd, so the front diff wasnt connected to the wheels.

Did 100 motorway miles the other month then changed oils. Both diff just nice and warm, not hot

now youve got me worried.

Edit. after Mikes post im now even more worried.

 

[Ben]

for the last 6 miles i was driving at 70mph.

big heavy tyres shouldnt effect it should they?

 

[karl webster]

If i remember right ben when gav had the diffs off jon they got quite hot.

 

[Crushers]

ummm, a completely disconnected diff will not get warm. it will not change in temp, period ...
unless...
either the t/case isn't disengaging properly
or
the hubs are faulty,not allowing them to disengage.

i would check one or both.

to check:
unlock hubs
spin each tire and other tire on the ground.
if the driveshaft spins then that is the hubs problem.

if unlock hubs does not spin the drive shaft then set both front tires back on the ground with hubs still unlocked.
manually turn driveshaft with 4WD disengaged. the driveshaft should turn freely.
if it doesn't turn freely then the 4WD selector inside the t/case is at fault.

HTHs somewhat.

 

[Ben]

thanks Karl.

fingers crossed its normal then.

Wayne, its the rear diff thats getting hot, not the front one.

 

[Crushers]

picture old man sitting with a coffee around the campfire, his hearing isn't the greatest so he thinks he hears one thing and then rambles out an conversation ... completely missing the point ...

paint me embarassed.

rear diff getting warm is normal, getting hot isn't.

 

[Ben]

I checked the oil level in the diff this morning, and managed to squeeze a bit more in.

Took it for another 12mile test drive after work, averaged 60mph.

Got home and the diff was still hot, almost too hot to hold my hand on.

It drives perfectly and theres no noise coming from the diff.

The backlash was set perfectly, that im confident of, but im a bit worried that ive set either too much, or not enough, preload on the bearings.

would either of those cause excess heat?

 

[Rob]

Too much preload on the bearings can easily cause heat build up, you might be experiencing thermal runaway. This is when a material is expanding due to heat which increases preload and makes the heat generation problem even worse. Not sure how the diff is set up but surely not enough preload would increase backlash

 

[jeepmadmike]

How did you set the preload?

 

[Ben]

Thanks Rob.

As per the FSM instructions. IMHO it didnt seem like a very accurate way of doing it.

It says:-

Place a dial indicator on top of the adjusting nut on the ring gear side.

(pic actually shows the dial gauge positioned against the adjusting nut, not actually on top of it.)

Adjust the side bearing for zero preload by tightening the other adjusting nut until the pointer on the indicator begins to move.

But after already doing those nuts up fairly tight anyway to set the backlash, i dont really see how the dial indicator would/should start to move?

the dial indicator is against a nut that is tightened against the bearing. tightening the nut on the other side, is supposed to what, some how push the other nut, that the gauge is positioned against, out?

really cant see that myself?

but thats what the manual says and thats what the pic shows.

 

[ModelMakerMan]

Yeah it does seem a little odd but thats just how its supposed to be done. Remember that you only tightened the bearing cap bolts by hand at this point so what is actually happening when you tighten the adjusting nut is you are pushing the bearing into the outer races which push against the nuts which pushes against the bearing caps which can move a little due to being a little loose. Remember the dial gauge is only measuring 10ths of mm.

 

[username_11]

i've read the entire thread now very nice cruiser

how have you found the kz on veg oil ? do you run 50:50 or have a heat exchanger


hot diff could be too little backlash. i aim for between 7 and 8 thou and take a reading of every other tooth lol

my lux diff has never got too hot to hold. same tyres, diffs and engine so fairly comparable

 

[Graham]

Hi Ben,

I would be inclined to park the 'cruiser up.
Pull the diff out again, yeah, it's a pain in the asse, but really, some thing there is just not right.
For the diff casing to get that warm, then who knows how hot the culprit is getting intside.
Might be an idea to put new oil in if you do decide to strip it open again.

Pull the axles, get the diff opened back up on the bench.
If you can hardly touch the diff housing, then I am sure you may find some "blue'ing" internally.
Before you get any metallic melting and pick up, I would have another good look, and check it is right.

Hope you find the problem.

Gra.

 

[Ben]

Yeah it does seem a little odd but thats just how its supposed to be done. Remember that you only tightened the bearing cap bolts by hand at this point so what is actually happening when you tighten the adjusting nut is you are pushing the bearing into the outer races which push against the nuts which pushes against the bearing caps which can move a little due to being a little loose. Remember the dial gauge is only measuring 10ths of mm.

that must be where i went wrong.

manual says to fully tighten them, i obviously missed the next bit where it said to loosen them.

i've read the entire thread now very nice cruiser

how have you found the kz on veg oil ? do you run 50:50 or have a heat exchanger


hot diff could be too little backlash. i aim for between 7 and 8 thou and take a reading of every other tooth lol

my lux diff has never got too hot to hold. same tyres, diffs and engine so fairly comparable

thanks.

it doesnt run as nicely on veg as the old 2.4.

but im currently running 70% veg to diesel, and it runs lovely! everything is standard, no heaters etc. although i am thinking of twin tanking it at some point and fitting heaters.

Hi Ben,

I would be inclined to park the 'cruiser up.
Pull the diff out again, yeah, it's a pain in the asse, but really, some thing there is just not right.
For the diff casing to get that warm, then who knows how hot the culprit is getting intside.
Might be an idea to put new oil in if you do decide to strip it open again.

Pull the axles, get the diff opened back up on the bench.
If you can hardly touch the diff housing, then I am sure you may find some "blue'ing" internally.
Before you get any metallic melting and pick up, I would have another good look, and check it is right.

Hope you find the problem.

Gra.

Really dont want to strip it all back down again, but i guess if ive got to ive got to.

going away on a 3 day laning and wild camping trip this weekend, so looks like its going to be some late nights this week to get it repaired on time.