H55f noise when coasting in H4

[Oldtoy74]

I've noticed last couple of times while on the beach & general bush work in H4, my box or transfer makes a noise when coasting in H4.
The noise does sound like a bearing of some sort, under load no noise, if then you take pedal off the juice you can hear it as the box transfers the internal load and then it goes away, when you pedal down you hear it again but then dissapears again.
It does not seem noticeable in H2 under load or coasting, any thoughts.

 

[cruiserdan]

Does it also happen with the hubs locked but the front axle disengaged?

 

[Malahki]

I bet its your front drive shaft. Very common among lifted 70's. Once lifted the angles at the U-joints become unequal. This also causes excessive wear on the splines on the slip joint. I had my D-shaft inspected, balanced and new U-joints installed twice with no improvement. It will only continued to get worse.

The best way to correct the problem is with a double cardan driveshaft. After replacing mine with a DC shaft the noise and all vibration is completely eliminated and runs smooth even at highway speed (on icey roads).

 

[cruiserdan]

Exactly why I asked if it was happening with the hubs locked but the front drive disengauged. I have a slight vibration with the front shaft turning in both 2 and 4wd (OME ~2.5 in lift).

 

[Oldtoy74]

Does it also happen with the hubs locked but the front axle disengaged?

No it does not, "..........while on beach I disengaged h4 button and drove with h2, no issues's

 

[cruiserdan]

In that case I would suspect the front transfer output bearing.

 

[Oldtoy74]

Can I get to that and remove without dropping the transfer, ????

 

[Malahki]

Mine didnt do it either in the beganing with the hubs locked and only in 2wd. As you described it only happened in 4hi and at a coast (as in no torque on driveshaft). I also thought it was front t-case output bearing. But trust me the problem is the drive shaft angles and it will keep getting worse!! It takes a while though. For me it was a whole winter of leaving the hubs locked. By the end of that winter it was really loud and constant when in 4Hi or 2hi with the hubs locked. But after having t-case rebuilt the problem had not gone away. Thats when I was convinced it had to be the driveshaft. Like I said the DC shaft completely corrected the issue

 

[Malahki]

Oh and just so you know you would have to strip the case to replace the front output anyway

 

[Malahki]

To prove my point check this video out and you will see exactly what I am talking about

 

[Oldtoy74]

If I put a dc shaft in and not touch the front output, would that rebalance that bearing load then, or I still need to look at replacing that bearing as well

 

[Malahki]

I am saying it is not the output earing at all. Mine was still in perfect condition when the T-case was rebuilt. To prove this remove your front drive shaft and run in 4hi. If its the output bearing you would still hear it.

Well you got the shaft out, mark it and then pull the slip splines apart. Grease the splines thoroughly and reassemble (simply greasing through the grease nipple is not effective at evenly greasing the entire length of the splines and over greasing can hydraulically lock your shaft solid which will then damage your diffs internal crush sleeve when the suspension cycles). Once the splines are properly greased and reassembled if you notice any improvement, it will further prove the problem is the poor shaft angles and not output bearing.

 

[Oldtoy74]

I just called a mob that sell these dc shafts, there not cheap, I need to provide measurements etc so he can quote me correctly

Did you get full new shaft or just put the new dc uni joint onto existing shaft.
I actually read your thread on the subject prior to you chipping in, so it's good you picked this up to clarify, much appreciated.
My other option is to remove air bags from Oldtoy, then who knows how my ride would feel then with the untried existing springs, either way it's still a cost my wife will not endorse in hurry.
I have exhausted my " asking for forgiveness as opposed to asking for permission"

 

[Malahki]

I replaced the entire shaft. If youve got the noise youve already got wear in the splines and adding a DC joint will not completely fix the problem.

I also had them use cross over flanges that mate the Toyota flanges to spicer U-joints. Two reasons for this; price and availibility. A Toyota DC joint is going to be a lot more expensive and Spicer U-joints are available every where.

I used 1310 Spicer sealed U-joints. Because they are not cross drilled for grease passages they are much stronger. I chose 1310's to ensure clearance of the DC joint on the stock transmission cross member. 1330 or even 1350 could be used on the diff end but I wanted them all the same

No DC shafts are not cheap but prices can vary greatly. Pats Driveline (Quality Gear) in Lethbridge AB quoted me $1500 just to add a DC joint to my shaft. Extreme Driveline in Red Deer AB, built me a brand new shaft including crossover flanges for under $700.

Places down south like Tom Woods could do it even cheaper but I didnt want to order long distance and risk screwing up the measurements

 

[Hulsty]

Mine did it too, was just a worn stock shaft, new shaft in and no issues. Think I put in a HZJ75 shaft

 

[Malahki]

Yup it all depends how you use your truck. If you only lock the hubs when you hit the trail a few times a month then a stock shaft will last a long time. If you daily drive in winter in Canada and rely on 4hi for safety then the DC shaft is the only way to go!!

 

[roscoFJ73]

Before you start spending money , have you tried greasing the splines? And do you know for sure the grease is reaching the splines?
I use to get a growl from the front and thats what it was.

EDIT i see someone has already suggested it

 

[watrob]

In that case I would suspect the front transfer output bearing.

Common issue this, there are no shims on the front output shaft unlike the rear output, so no adjustment. Its made worse after a lift, a combination of worn parts right thru from the front axles, diff, uni-joints, slip yokes, wrong tail shaft angle and finally the output shaft bearing, also the needle bearing in the t-case also allows play.

This all adds to that GRRRRRRRRR you get when you lift your foot off in H4, there will always be a little play in the front output shaft.

Seen this on fully rebuilt boxes also, tell tail sign of a worn front output shaft is a weeping oil seal. To test take your front tail shaft off and see how much movement is in the shaft, also check the flange nut is not loose as well?

Replace the oil seal with a OEM one as they are the best to use? but like other forum members have said your angles need to be spot on and check your spline is not over packed with grease?