LC100 front diff issue - NEED HELP (2 Viewers)

[7amannnyy]

Hey MUDders,

New member here! I recently picked up a 2003 Land Cruiser LC100, GCC specs, with the 1FZ-FE engine. Loving it so far – solid rig and a dream to drive… mostly.

### A few issues I’ve run into and hoping to get some insights:

**1. Sluggish Driving (Since Day 1):**
The truck always felt a bit sluggish, especially on the highway. RPMs are around 2,000+ even at cruising speeds, which seemed a little off to me.

**2. Reversing Problem:**
Earlier today, I noticed something strange while reversing. If I turn the steering wheel fully left or right, the truck rolls slightly and then completely stops — like something is locking it up. Straighten out the wheel, and it moves again.

**3. Whining Noise + Sluggish Forward Drive:**
Forward driving is okay but feels heavier than it should. I also recently started hearing a whining noise from the front-left at highway speeds.

**4. Mechanic Diagnosis:**
Took it to a local shop — the mechanic pulled the front drive shaft and said the front differential might be the culprit. After removing the shaft, the truck drives much better (no more dragging feel or noise).

He said it’s safe to drive without the front shaft for now, while I sort out the front diff issue.

**5. Center Diff Lock Confusion:**
Did some research and found that driving without the front shaft is fine *as long as* the center diff is **locked**. So I tried pressing the CDL button:

- I hear a relay click, but the truck won’t move.
- Press it again — it moves fine.
- No CDL light on the dash either (maybe the bulbs are out?).

### My Questions:

1. Is it safe to drive without the front drive shaft in my case?
2. Could the center diff have been **engaged all along**, causing the front diff to fail?
3. Is it normal for the CDL button to behave like that (clicks but no movement)?
4. Should I be seeing a dash light when CDL is engaged, or is it common for bulbs to be out?
5. Any long-term issues I should worry about driving like this temporarily?

I’m new to this platform and not very mechanically inclined, so I really appreciate any advice or explanations you guys can offer.

Thanks in advance!

 

[excessive]

I think your center diff is locked, which would explain #2 and #3 . you might try pulling off the CDL actuator motor and manually putting the center diff in the unlocked position ? ?

 

[7amannnyy]

I think your center diff is locked, which would explain #2 and #3 . you might try pulling off the CDL actuator motor and manually putting the center diff in the unlocked position ? ?

Thanks a lot for the reply

a little update

after letting the car sit for a while

if i press the CDL button

i hear relay click and the button keeps pressed in and the vehicle moves normally

If i press again

the relay clicks again and the button comes out (depressed) and the vehicle is free even in drive it feels like it's in neutral

is this normal?

 

[excessive]

the symptom you experience in #2 is what it would feel like when your center diff is locked

 

[2000UZJ]

Well, one issue caused another. If you have the front driveshaft out, you'll 100% need the CDL to be locked to move. If you have it unlocked and the truck only revs in gear, the CDL is working. The lights are burned out.

 

[7amannnyy]

Thanks a lot for the reply

a little update

after letting the car sit for a while

if i press the CDL button

i hear relay click and the button keeps pressed in and the vehicle moves normally

If i press again

the relay clicks again and the button comes out (depressed) and the vehicle is free even in drive it feels like it's in neutral

is this normal?

so does this mean my front diff was probably okay? and the CDL was locked?

 

[7amannnyy]

Well, one issue caused another. If you have the front driveshaft out, you'll 100% need the CDL to be locked to move. If you have it unlocked and the truck only revs in gear, the CDL is working. The lights are burned out.

• is it okay to drive with the Drive shaft out? i use this truck as daily, is there anything else to be done or i can drive just as it is? i don't do any offroading
• what if i want to re attach the drive shaft? if the front diff needs to be replaced how much will it cost probably?

 

[Bisho]

so does this mean my front diff was probably okay? and the CDL was locked?

It seems likely. If the center diff is locked and you turn the front wheels far it will cause binding (especially on a dry, firm surface). You should not lock the diff (when both driveshafts are on) on pavement. It only takes a few minutes to reinstall the driveshaft and see what you get.

You can continue to drive without the front driveshaft, but I doubt there is an issue with your front diff. When you are driving its spinning, whether the driveshaft is attached or not, because we do not have the ability to unlock the hubs.

 

[2000UZJ]

• is it okay to drive with the Drive shaft out? i use this truck as daily, is there anything else to be done or i can drive just as it is? i don't do any offroading
• what if i want to re attach the drive shaft? if the front diff needs to be replaced how much will it cost probably?

There is no risk to driving with the Center Differential Locked. I drove this way for a few months when my front differential failed. Just be aware that the driving dynamics are changed as it's now rear wheel drive.

If you can drive it, you can find another mechanic to get a second look. It's very, very rare for differentials to just fail. Typically when they fail the gears break off creating a very loud sound and violent shaking in the cabin. I would get another opinion and go from there.

 

[TahoeZ]

Sounds like your CDL bulb is burned out. Your other “symptoms” are just indicative of driving with the transfer case locked.

 

[7amannnyy]

It seems likely. If the center diff is locked and you turn the front wheels far it will cause binding (especially on a dry, firm surface). You should not lock the diff (when both driveshafts are on) on pavement. It only takes a few minutes to reinstall the driveshaft and see what you get.

You can continue to drive without the front driveshaft, but I doubt there is an issue with your front diff. When you are driving its spinning, whether the driveshaft is attached or not, because we do not have the ability to unlock the hubs.

ahan
so i might have by mistakenly pressed it and i didn't got to know because the bulbs are burnt out

but i drove like that with 100km speed for like 20kms
and i heard whining noise

would that might have busted the diff even more?

 

[7amannnyy]

There is no risk to driving with the Center Differential Locked. I drove this way for a few months when my front differential failed. Just be aware that the driving dynamics are changed as it's now rear wheel drive.

If you can drive it, you can find another mechanic to get a second look. It's very, very rare for differentials to just fail. Typically when they fail the gears break off creating a very loud sound and violent shaking in the cabin. I would get another opinion and go from there.

your front diff failed and you removed the drive shaft

what about the front diff?

was it still attached or removed?

 

[7amannnyy]

Sounds like your CDL bulb is burned out. Your other “symptoms” are just indicative of driving with the transfer case locked.

Thanks

I'll get it checked out with another mechanic by weekend and report back here

BTW

As i don't do much off roading

is it better to keep the drive shaft detached or better to attach it?

what's recommended overall?

does it get better fuel MPG?

does it make the car lighter?

 

[Bisho]

Thanks

I'll get it checked out with another mechanic by weekend and report back here

BTW

As i don't do much off roading

is it better to keep the drive shaft detached or better to attach it?

what's recommended overall?

does it get better fuel MPG?

does it make the car lighter?

There is no advantage to leaving the driveshaft off. The whole differential mass is spinning one way or the other. What you would lose is the advantage of all wheel drive, which can be a benefit when it does rain or if you are on a loose surface (sand). You will not get better mileage, and the truck will only be 20 lb lighter, which will have no impact.

 

[7amannnyy]

There is no advantage to leaving the driveshaft off. The whole differential mass is spinning one way or the other. What you would lose is the advantage of all wheel drive, which can be a benefit when it does rain or if you are on a loose surface (sand). You will not get better mileage, and the truck will only be 20 lb lighter, which will have no impact.

one last thing
as i got it used
the only maintenance item i did on my truck is i got the air conditioning fully serviced
new condenser
new compressor
all lines cleaned
evaporators cleaned

what about the differentials
should i get the fluid changed?
the transmission clunks sometimes from 2nd to 3rd
like the shifting is hard

 

[TahoeZ]

These are not low/no maintenance vehicles. List of recommended maintenance items here:FAQ - 100-series FAQ - https://forum.ih8mud.com/threads/100-series-faq.30754/

Yes, change differential, transfer case and transmission fluids.

 

[7amannnyy]

These are not low/no maintenance vehicles. List of recommended maintenance items here:FAQ - 100-series FAQ - https://forum.ih8mud.com/threads/100-series-faq.30754/

Yes, change differential, transfer case and transmission fluids.

the car is at half million kms
will it be safe to change transmission fluid
i don't know when it was changed last

 

[TahoeZ]

Differing opinions on that topic. Personally I would change it. You’ll want to do a fluid exchange using the vehicle’s system. No high pressure flush.

 

[7amannnyy]

Differing opinions on that topic. Personally I would change it. You’ll want to do a fluid exchange using the vehicle’s system. No high pressure flush.

meaning connecting it to a machine that will be connected to the transmission hoses

while the truck is idle
it will change the fluid
correct?

 

[TahoeZ]

You’ll need to spend some time familiarizing yourself with these vehicles. Timmy the Toolman and 2001LC have a lot of great YouTube videos on the 100 series.