greyheadedguy

I think I have a differential problem with my "Gem" of a truck... With the truck in two wheel drive only and on sand or gravel my left rear wheel will spin, it breaks loose when accelerating on the sand or gravel while already moving. And yes both rear wheels were on sand when this happened. To my knowledge I do not have a limited slip differential. So I found myself on a dirt road, I came to a complete stop and then stomped on the accelerator and both rear wheels spun... I only did this for a brief time to see what would happen. When I got out to look at the dirt both rear wheels had spun about the same distance. The other day I was backing up my drive way and I heard tire squeal and when we got out my left rear wheel had spun and left rubber on my concrete driveway. Is this normal with these Toyota 4x4 Pickups?

I look forward to responses and thoughts...

bearcat2

Yes, this is normal and a sign of an open diff. With a locker or to a lesser extent with a limited slip both wheels would spin. If both wheels are getting poor traction then even with an open diff often both will spin (as yours did on the dirt road) but if one is getting better traction than the other the open diff will send power to the one that slips

greyheadedguy

What do you mean "with a locker"? Every other Toyota truck I have driven, albeit all 2 wheel drive, always spun their right rear if one was going to spin. I have never seen a vehicle spin it's left drive wheel... I have a drive over curb attaching my driveway with the road so when my front wheels hit the ramp on the curb my back wheels are almost 16 - 20 inches higher than the front wheels so most of my weight is on my front wheels... But both rear wheels were on my clean concrete driveway.

There has been "stuff" done to this truck. Very little of it was done right so I am still figuring out what they did wrong to it and fixing it. Could it be a failing differential as I get a bit of noise from it. The noise is a hum or a rasp or his... I'm not questioning what you are saying I'm trying to better understand my truck. I want this truck to be like Old Blue was, a truck I can jump into any day of the week and be completely confident to drive it anywhere, 1 mile or 2,500 miles...

grey

Co_94_PU

iTrader: (-1)

You need to know what you have in the diff, is it a standard open diff or is it locked or maybe an LSD.

Your full throttle test on loose dirt is flawed.

What you want to do is lift both tires of the ground (floor Jack under the differential housing, jack stands under the frame rails). If you spin the right tire top forward and the left tire spins in the same direction you have a locked or LSD diff, if it spins in the opposite direction it is a standard "open diff".

In regards to which tire spins in an open differential and your experience of " it is always the right tire ", physics!! the way the spider gear is designed and the rotation direction of the drive shaft dictates which tire wants to spin when the traction is equal. Once the one tire starts to spin the system is designed such that this wheel will tend to get all the torque..

.. Anyways Jack it up and check it, if you want to know for certain if it's a welded diff, a spool, or an LSD you will have to pull the third member out.

greyheadedguy

I forgot to mention I have had the truck in the air while working on it and have spun the wheels. When I spin one wheel forward the other wheel spins the opposite direction. Which as I understand means I have an open differential right?

grey

ev13wt

Just lift one ifs side of the truck until the right rear stops spinning and the right left starts?



But seriously. Drive a slow left turn on dirt and "hit it". Left will spin because that side of the truck is lighter.
You have open diffs.

That means in 2WD you really only have 1WD, and in 4WD (if you attach the front wheels to the front axles via the hub selector) you really only have 2WD.

Never drive 4WD on pavement. You don't have a middle differential (transfercase diff). Things will break sooner than later.

greyheadedguy

Then why did I spin both rears on the dirt road?

grey

akwheeler

If you hit it hard enough on a loose surface both tires will spin even with an open diff. The only way for you to tell if you have an open diff or a worn out limited slip is to pull the axles and the third member and take a look. You could check the axle codes on your truck to see what it came from the factory with, but a previous owner may have changed that.
Which tire spins depends on the tire tread, tire pressure as well as vehicle loading and the ground you are on. More weight on one side or a bad shock/ slightly bent frame or weak leaf spring can influence which tire gets more bite, the other one will spin.
If you are not hearing any grinding clunking or howling from the rear end you don't have an immediate issue to worry about so you need to ask yourself "self, do I spend enough time on the dirt to need a limited slip?" or "Self, do I go rock crawling or mud bogging and need a locker?" If the answer to both questions is no then you should leave well enough alone, it won't come apart catastrophically without some obvious noises.

greyheadedguy

This is my prospecting truck and my daily driver. I am trying to confirm that I'm not going to get stranded by a bad differential. Most areas I go to are not bad, some are 4 wheel drive only, steeps slopes lots of rocks and gravel

This truck has had some really bad work done to it before I got it as well some major neglect. When I got the truck it was no where close to being road safe. It wasn't running and supposedly just needed an engine. Once I got the new engine in it I had no brakes. I pulled the drums and both drums were packed with sand and gear oil. I pulled both axles and replaced bearing and seals. The shop that pressed off the old bearings said it was a good thing I did this, one of the bearings squirted water when he removed it. This is also why I have questions... The differential's oil looked like coffee with a little cream, dark brown and opaque.

coryc85

Sounds to me like you are worried about this diff failing on you. Pull it out and take a look. You'll know for sure what is in there and you can inspect the bearings and gears. If gears and bearings are not noticably bad, you can set pinion preload, carrier bearing preload and backlash and hopefully get many more miles out if it. Only problem is that this starts going down a rabbit hole. Might end up needing new gears, bearings, Crush sleeve, pinion seal, and ujoints before it's all over.

greyheadedguy

This is my daily driver, so down time needs to be minimal. I've never been in a differential before and a friend of mine has told me a 'shade tree' can't rebuild one, at least he couldn't and he had a shop in Indianapolis. He ended up sending it to a specialist... I've heard trans axles are a real pain in the butt and require special tools, is this true with Differentials?

scope103

Here's the 1993 manual for the differential. http://web.archive.org/web/201102060...35differen.pdf Too many SSTs (Special Service Tools) for my personal taste. But there are plenty of folks on this forum who have re-built differentials, and some of them have posted comprehensive photographic guides.

More than I would like to take on (particularly considering the limited evidence of shortcomings in your differential), but you can make your own decision.

ev13wt

OPs diff is just fine. They will take a TON of abuse before they fail.
How about: 50000 miles with a bad pinion bearing and actually moving up and down when you wiggle it?

greyheadedguy

What was that a piece of?

RJR

I agree. OP, nothing you have posted has suggested there is anything wrong with the diff. I would NOT take it apart based on the evidence so far. A couple of things you can do to ease your mind.
- Check for excessive backlash by blocking the wheels, putting the truck in neutral, and grabbing the rear drive shaft and trying to rotate it. Should only be a couple of degrees of rotation.
- Jack up one rear wheel with the truck in gear and rotate the wheel through several turns, listening and feeling for clicks, hesitation, or other lack of smooth operation.
- Pull the drain plug and check for contamination in the oil. You can even send a sample to Blackstone Laboratories for analysis if you are concerned. $28 will tell you if there is an abnormal amount of metal in the oil.

Otherwise, in the absence of funny noises or clunks, it's very unlikely anything is wrong.

Open diffs split the torque to both wheels equally, within less than 1% difference side to side. One wheel will almost always break loose before the other, due to slight traction and weight differences. Because dynamic friction is generally less than static friction, once one wheel breaks loose it will tend to spin uncontrollably while the other remains stationary. On what looks like equal traction surfaces, it's anybody's guess which wheel will break loose first.

greyheadedguy

Kind of like I'm checking for play in the universals? But at the flange? I have a vibration at highway speed, so I need to get under there and check the drive line anyway... Feels like a bad or failing universal...


This I can do, just have to get under there to do it.

Due to circumstances I have drained and changed the differential oil twice since I've had the truck and pulled a little bit out not to long ago. it looked and smelled normal...

What about the wrasping noise? Some trips it is louder that other trips. What I mean is some trips I have to close the window to the bed and other trips it's fine, I can still hear the radio...

I do need to work on the suspension, who knows how old the shocks are on that truck. Is actually something I have planned, just haven't done yet. New shocks all the way around my 85 Toyota 2x sure made a difference in the way it rode and drove...

Thanks,

grey

greyheadedguy

I have a factory service manual for the truck. My friend, the retired mechanic, has told me from time to time that I shouldn't be trying to do the things I do to my truck, but he is old school (92 years old) and did own a shop and I'm sure thinks most people are incapable of working on their own vehicles... He was rather impressed with me when I did rings and rod bearings etc. on my 85 22R engine...

I think part of my problem is I am getting tired of working on this truck... It turned into more of a project truck than it was supposed to be...

grey

greyheadedguy

What is that a piece of?

ev13wt

A piece of a pinion I think.