I've got an 86 4 runner w/ auto and ifs

I recently bought used front and rear thirds w/ 5.29's from two different folks on the net. The rear had a new yukon R&P and older LSD. The front came open and complete with axles and I never opened it up.

I got it all installed the other day. When i test drove it (in 2wd) i could definitely hear the rear making a slight whining noise and when i let off the gas the truck slowed much slower than before. I've never gotten new gears so not sure if that was normal.


I also test drove the truck in front wheel drive (removed driveshaft) with no problems.

When I put the truck in 4wd and drive in a straight line, it behaves as I would expect it too.

In 4wd drive when turning it makes a clunking noise that sounds like it is coming from the t-case area and the rear wheel will chirp.

My first thought was that maybe the guy who sold me the front lied and that they weren't 5.29's. If this were true would it drive fine going straight in 4wd.

Then I remembered how people with lockers talk about chirping tires around turns. Do you think the LSD could be bad and be acting more like a locker?

Any ideas? I've been working on this thing since spring and thought the gears were going to be the last thing I needed to be ready for winter. :pat:

 

It's not the diffs that are causing the chirping. It is the fact that you're driving in 4WD on dry pavement. DON'T DO THAT!!! Your binding up the drivetrain since the front tires need to turn faster than the rear in a corner. This is causing the rear tires (less weight on them) to chirp.

 

So you think that's all it is?

I'd driven the truck before in 4wd when dry, like after I got on dry payment during snow, and it didn't behave this way. You did get me thinkin' though and I was doing my test with 5.29's and 31's so that would probably compound the issue- alot.

I guess i will try to get it offroad or in the wet for more testing. Maybe this will give me an excuse to get 5.29's put in my old third just in case.

 

Okay so i was driving around today to run some errands.

With the truck in 2wd I still get the clunking popping sounds from the rear but only when I turn left. It only seems to do it from a stand still. If i am moving and turning left, even on the gas, everything seems fine. But going real slow or from a stand still I hear and feel it.

I jacked up each side of the truck. I can rotate the tires on either side a few inches back and forth. The drivers (left) side has no resistance and just feels looser than the passengers side.

Could I have knocked something loose when installing the third?

Any ideas?

 

You may have a bad LSD. I'm not real experienced with them (I run full lockers) but it would seem to me that they should be the same on both sides. Another possibility is something with the brakes. I'd pull the drums and take a look inside. Maybe something came loose or broke on the left side.

 

there are oil splash guards that snap into the rear axle tubes, perhaps you've bumped one of those loose?

did you use the proper lubricant for the LDS? Some take an additive to allow them to work properly.

other than that, I don't have an answer...

 

Do you have a locker or lsd?

 

I have an lsd.

Are the splash guards the small metal plates in the housing just before the axle tubes. If so I originally didn't pull the axle all the way through those, cause they looked like the could pop loose easily. But on one side I had trouble getting the axle back in and pulled it back out some. I could have knocked it loose.

I will be pulling the third as soon as I have time, not for a few days at least.

Thanks for the help guys.

 

What kind of limited grip unit is it. Gear driven or clutch packs. If clutch driven it may be the clutches are sticking.

 

if your lsd is working like a locker, thats a good thing... lsd isnt supposed to slip until a certain amount of torque is applied... usually the threshold is very low, so they jsut slip and dont do much of aiding in traction.. when comapred to a locker.. they help out a good deal when compared to an open diff... there is no substitute for a locker when full traction is needed

 

Well bikeguy......what happened? If you had a whining noise that would concern me a little. Most of the time it's a gear pattern that is not quite right.

 

Well I found a decent deal on a new third so I bought that. Its hasn't come yet so I've been driving occassionally with the LSD. I had originally put an lsd additive in when i installed the third. I got in contact with the original ower and he doesn't know what brand it was (but THINKS its a toyota lsd), and ran no additives.

I flushed the gear oil out a few times and I'm running straight gear oil. I did see an unusual amount of metal fines on the drain plug magnet. I was able to drive around in 2wd just fine without much binding. I did some more flushing and draining of gear oil. I took it on a few trips with no problems.

The other day it took it out for a 35 mile highway drive. When i got to my destination (a mall) I would get the binding whenever i turned the wheel the slightest bit to the left. It was almost as bad as when i tested in 4wd. The binding (when bad) seem to come all the way up through the t-case so I don't like it. I'm hoping the new third comes before snow comes, because the truck is my DD in the winter (thus the reason wanting an lsd over a locker). Also then if i can find a shop, maybe i can get the lsd looked at. When i do replace thirds I'll update with what i find.
DAve

 

Sounds to me like if he doesn't know what LSD it is then he probably doesn;t know if it needed the LSD additive or not. It's probably a clutch driven unit and your clutch packs are sticking. That's my guess. If it's a torsen or gear driven style them I have no clue off the top of my head