NEED HELP! Center dif lock/ 4.88 regear question! (3 Viewers)

[jordancollard97]

Hello all.

Going to try and keep this concise and clear.
1994 triple locked Land Cruiser. Previous owner re-geared it to 4.88s. Still running stock tires.

My question is- will the factory center lock (and the rear and front locker for that matter) still work as normal with a regear?

The reason I’m asking:
When I am in 4low, and the center dif lock is engaged- the rear tires seem to chirp/ slip/ hop.
I don’t notice it when the center dif isn’t engaged.
It even does this when driving straight on grass/ gravel- just about any time the 4WD low is engaged with center dif lock.

It will still move and drive- and it’s not constant. Probably about every 10 feet.
Like I said, sort of chirps and the rear tires seem to slip. Almost remind me of crawl mode in a Tacoma.

Is this normal? Is it not? Any suggestions? Could it have to do with the regear or would the two be unrelated?

 

[BuzzAZ]

Properly regeared diffs will work just fine. Chirping/chatter around sharp turns is normal, but not driving straight. Sounds like something is binding and I can’t imagine it’s doing your transfer case any favors.

 

[LongDuck]

Some thoughts - as I've been driving on 4.88s the whole time Ive owned my LandCruiser; on 35" tires, it helps with torque on oversized tires. Since you're on stock tires, I'd imagine that torque is significant when battling tire adhesion, hence the noises coming from your diffs.

You shouldn't ever engage your locking axles on pavement if you care at all about your diff gears and transfer case. The locked axles are for dirt where sand, mud, and rocks allow some slippage. Locking them on pavement requires your tires to become the shock absorbers in this situation, which is what you've described - chirping from the gears forcing the tire against the pavement until they slip all at once.

Center Diff Lock is more forgiving on pavement, as it leaves the front and rear axles to solve their own problems, but sends equal torque to each from the engine instead of allowing slippage at the transfer case.

As I don't have the coveted factory locker dial, someone who does can correct me if I've misunderstood, as I know the dial connects lockers in a rotary sequence...

Point being, it's normal - but don't do that (*on pavement).

***Re-read that you're saying this happens when driving in a straight line. Not normal. Are you sure it's the tires? Or is your transfer case doing something weird?

 

[jordancollard97]

Some thoughts - as I've been driving on 4.88s the whole time Ive owned my LandCruiser; on 35" tires, it helps with torque on oversized tires. Since you're on stock tires, I'd imagine that torque is significant when battling tire adhesion, hence the noises coming from your diffs.

You shouldn't ever engage your locking axles on pavement if you care at all about your diff gears and transfer case. The locked axles are for dirt where sand, mud, and rocks allow some slippage. Locking them on pavement requires your tires to become the shock absorbers in this situation, which is what you've described - chirping from the gears forcing the tire against the pavement until they slip all at once.

Center Diff Lock is more forgiving on pavement, as it leaves the front and rear axles to solve their own problems, but sends equal torque to each from the engine instead of allowing slippage at the transfer case.

As I don't have the coveted factory locker dial, someone who does can correct me if I've misunderstood, as I know the dial connects lockers in a rotary sequence...

Point being, it's normal - but don't do that (*on pavement).

***Re-read that you're saying this happens when driving in a straight line. Not normal. Are you sure it's the tires? Or is your transfer case doing something weird?

You know… it’s possible it’s the transfer case??
That might make sense, because it definitely feels as if some thing is not catching.

It feels like binding or slipping. But again, I only feel it when the center dif lock is engaged.

 

[MMaxim]

Hello all.

Going to try and keep this concise and clear.
1994 triple locked Land Cruiser. Previous owner re-geared it to 4.88s. Still running stock tires.

My question is- will the factory center lock (and the rear and front locker for that matter) still work as normal with a regear?

The reason I’m asking:
When I am in 4low, and the center dif lock is engaged- the rear tires seem to chirp/ slip/ hop.
I don’t notice it when the center dif isn’t engaged.
It even does this when driving straight on grass/ gravel- just about any time the 4WD low is engaged with center dif lock.

It will still move and drive- and it’s not constant. Probably about every 10 feet.
Like I said, sort of chirps and the rear tires seem to slip. Almost remind me of crawl mode in a Tacoma.

Is this normal? Is it not? Any suggestions? Could it have to do with the regear or would the two be unrelated?

Almost sounds like the previous owner stopped after regearing just one axle.

 

[jordancollard97]

Almost sounds like the previous owner stopped after regearing just one axle.

But being that it’s full time 4WD… wouldn’t it bind constantly?

 

[BuzzAZ]

No. It’s more of an AWD system until the CDL is on. When you lock it then it’s like a traditional 4WD system. That’s why I said you’re probably not doing your transfer case any favors- it may be binding, causing power to shift away, binding, causing power to shift away, repeatedly as you drive around. You just don’t realize it because it’s shifting power before you get to the tires chirping.

I’d take the front driveshaft out and see if your problems go away. If they do, then you have something causing the back wheels to turn at a different speed than the front. It may be mismatched tire sizes, mismatched gear ratios, etc. If it doesn’t, then you either have a transfer case problem or a rear diff problem. You know the PO jacked around with the diff so I’d start there.

 

[MMaxim]

But being that it’s full time 4WD… wouldn’t it bind constantly?Only when center differential is locked

It will act like an open diff in 4Hi, allowing axles to rotate at different rate. Will bind in 4Low when center diff is locked.

 

[Evil80Forces]

But being that it’s full time 4WD… wouldn’t it bind constantly?

yes, it would bind constantly going in a straight line no matter what you have engaged. the wheels would turn at different rates and inturn the prop shafts would turn at different rates. locking the center diff would not change that. unlocked or locked, the prop shafts are turning at the same speed according to the axel diffs.

 

[MMaxim]

yes, it would bind constantly going in a straight line no matter what you have engaged. the wheels would turn at different rates and inturn the prop shafts would turn at different rates. locking the center diff would not change that. unlocked or locked, the prop shafts are turning at the same speed according to the axel diffs.

Isn't the whole idea of a differential to allow wheels/axles to rotate at different speeds? When you make a turn your wheels/axles spin at different rate, but if your center, front or rear diffs are not locked you experiencing no binding.

 

[Evil80Forces]

Isn't the whole idea of a differential to allow wheels/axles to rotate at different speeds? When you make a turn your wheels/axles spin at different rate, but if your center, front or rear diffs are not locked you experiencing no binding.

when going in a straight line the center diff should provide equal power to each axel. if it's doing that and the axels are geared different it should cause a problem. at least that's how i understand it.

 

[tmxmotorsports]

Call previous owner.

 

[tmxmotorsports]

Also why would someone regear to 4.88 with stock size tires is crazy to me

 

[jordancollard97]

Call previous owner.

It was done before him.

 

[jordancollard97]

yes, it would bind constantly going in a straight line no matter what you have engaged. the wheels would turn at different rates and inturn the prop shafts would turn at different rates. locking the center diff would not change that. unlocked or locked, the prop shafts are turning at the same speed according to the axel diffs.

See- I’m getting this answer from half of the people.
And another from the other half.

 

[tmxmotorsports]

See- I’m getting this answer from half of the people.
And another from the other half.

Two logical answers and there's also the Flux capacitor in the transfer case lol

 

[jordancollard97]

Two logical answers and there's also the Flux capacitor in the transfer case lol

Yes.

I’m just not understanding how a full time 4WD system that pushes power to both axles could operate effectively at highway speeds and daily driving conditions with two different gear ratios.

Maybe I’m missing something. Hoping to get clarity before I go tearing things apart.

I was crossing my fingers that people would hop on and say some slipping/ driveline binding was totally normal and to carry on

 

[tmxmotorsports]

When I said Flux capacitor I'm taking about the viscous coupler it will act funky in the situation with cdl on

 

[tmxmotorsports]

So thinking about it all I would say both axles have been regeared if they have. That being said if not I kinda guessing here that the ABS system would pick up on all that in high range.? That would be to totally different speed sensor speeds front to rear. Anyways just my brain fart. Worse case tear the axles apart and find out 100%

 

[MMaxim]

So thinking about it all I would say both axles have been regeared if they have. That being said if not I kinda guessing here that the ABS system would pick up on all that in high range.? That would be to totally different speed sensor speeds front to rear. Anyways just my brain fart. Worse case tear the axles apart and find out 100%

Put your truck on 4 jackstands, activate all diff locks (center, frond and rear). Rotate any one wheel and see if all other rotate at the same rate. That will eliminate the possibility of different gear ratios in your axles.