Well to make matters worse, there seems to be a little play in the u-joint closest to the transmission housing. Back to the garage...More to come.

 

The groan or whine seems like it would be a U-joint getting ready to go.
Did you replace both U-joints when you did the driveshaft?

 

Ordered it from www.1sttoyotaparts.com with my clutch parts. It's an OEM ujoint. part number is 04371-35051

 

Thanks for the info.

 

no problem.

 

Well I am fairly certain the driveshaft is not the issue any more. I put her back up on jackstands and ran her up to 65 mph with the help of a friend of mine. There is a pretty serious 'grinding' noise coming from inside the differential. So I decided to drain the fluid and I found a pretty good amount of metal flakes on the plug and in the fluid. There are no shavings, just a bunch of little flakes. I haven't towed anything at all, I put the Mobil1 75w-90 Synthetic in back at around 65K. I am at 90K now.

What gives?

 

Actually that's pretty normal. If you are concerned, pull the 3rd, without the e-locker it's easy.

Good luck

 

Is it suppose to look like metal flake paint? I mean there are no big pieces but the fluid was almost iradescent there was so much in there. I really don't remember seeing that the last time I changed it.

 

So are you still hearing a groan now?

 

I have same symptoms on my 4wd remember..

 

Oh yeah at 67-68 mph It groans pretty bad. I am going to switch the fluid out today when I get back home.

It was really bad when I had her up up jackstands, but the angle was more severe because the suspension was more extended being that the back wheels were off of the ground about 2 inches. It was definately coming from the rear driveline somewhere, The u-joints are tight. I also took the runner off of jackstands and started it up, put it in neutral with the brake on and rotated the driveshaft back and forth. There is some play in the driveshaft and clunking noise coming from near the pinion flange. Don't know if this is normal or not.

 

oh man, you still haven't got this thing licked yet?

 

Well the driveshaft lengthening did take care of the bulk of the vibration near the front where the slip shaft goes into the transmission. So that part has been resolved...now this

 

There is always some play in the differential, so that is normal. The metal flakes in the gear oil may be a little excessive, but you will always have some.

It's possible you could have a worn bushing in the slip yoke, (trans output) that's not uncommon. Which is why I prefer the slip-joints that the 4x4's have.

Good luck.

 

I was reading some posts on ih8mud and some of those folks were complaining that loose pinion nuts cause groaning and/or roaring coming from the diff area at the speed I am noticing the noise, so I am going to look at the pinion nut tonight to see if it is loose. Any thing particular I should know or be aware of before doing this?

 

I have been following this thread from the begining hoping you would find a solution to this so I can try on my truck.

I own an 89 4Runner and I'm aware that the suspension on my truck is totally different than yours, but it sounds like we might have a similar problem. I installed OME rear leaf springs last october and since then have been unable to get rid of the grinding noise comming from the rear axle when I let off the gas and let it coast for a bit. The noise is noticeable at 45mph and higher speeds. I sent the driveshaft to get balanced and the shop told me the u-joints were ok. So now I guess I'll check the pinion nut also to see if it's loose.

Someone on another bb suggested that I check the following:
straightness of axle shafts
pinion bearings
carrier bearings
side gear thrust washers
check cross pin in spider gears for play
rear output shaft bearing on t-case

Not sure how much of the above applies to your truck, if it does you might want to check it out.

Good luck and hope you find the cause of the problem soon!!

 

more than likely if you've never regeared or had any work done with the 3rd then the nut will be tight. it's staked in place and shouldn't loosen. be careful if you decide to loosen or tighten it yourself because that's what crushes the crush sleeve to provide bearing preload and if you tighten it too much you'll crush the sleeve too much and end up with too much preload, on the other hand, loosening it will cause you to lose the preload.

Another thing to keep in mind is that with a lift and bigger tires there's going to be "some" vibration somewhere that you won't get rid of, just a catch-22 of modding.

 

So what ever happened?

 

It's still there I looked at a 99 Limited 2wd yesterday and my slip shaft is in about a little more than 1/4 inch further than stock. I also noticed the it has almost 0 degrees of angle on both ends of the driveshaft where mine is close to zero at the trans end and 'not' zero on the pinion end. Not a huge difference but some difference none the less. A double cardan yoke on the trans end should cure my problem I hope. Another cure would be to lower the trans cross-member to zero the angles. I am going to give Jesse a call at high angle driveline I guess...I have to get my liftgate repaired/replaced first. $1000 ouch!!!!

 

http://www.vibratesoftware.com/

This is wonderful info!!!!