62 T-Case: grinding on 4WD engage at speed?

[JBBenson]

I have searched the forum, haven't found exactly what my problem is:

Just replaced the solenoids, and the T-Case shifts into 4WD HI and back again no trouble, when the truck is stopped. When in 4WD HI or LO there are no abnormal sounds from the T-cas or transmission at all.

I have verified by crawling under truck and trying to turn front drive shaft, hubs unlocked.

The problem is at speed, there is a nashing sound as soon as I push the button for 4WD HI. I always switch quickly back, so I don't know if it will engage at all.

The solenoids have never worked properly on this truck, I have always swapped hoses (truck parked) so I don't know if it was always like this.

Any ideas?

 

[Spook50]

I never shift into 4WD if I'm going any faster than 5MPH. Remember, you're engaging one gear onto another and if the spinning gear is moving too fast, the non-spinning gear engaging to it won't catch onto the teeth and will just "float" there, grinding away without properly engaging.

 

[Moby]

Really? I engage 4WD high range at speeds between 20 and 30 mph. No trouble for 8 or 9 years of this...

 

[JBBenson]

The purpose of the vacuum engage is to be able to shift at speed, the diaphram pushes the gears together slowly until they mesh.

Isn't it?

(Somebody please correct me if I am wrong...)

I think that I may have a leak in a vacuum hose that doesn't give the diaphram enough pressure to engage....or something else.

I was hoping the new solenoids would be the end of it.... but that would be too easy now, wouldn't it?

 

[agent orange]

Im having nearly the same problem. My tcase makes a wierd noise sometimes coming out of 4wd and i think my vacuum shift mechanism is to blame. Im gonna tear into it this week, hopefully ill come up with something easy to fix. If all the vacuum lines to the tcase are fine, what parts would likely to be bad in the vacuum shifter mechanism? Im thinking the seals would be more likely to go than the diapraghm itself.

 

[JBBenson]

My thinking is if there is not enough pressure on the plunger, that the two gears do not mesh but just float "out-of-sync" so to say, and chatter away.

I am hoping someone with more knowledge and experience than I will know
what is up...

 

[JBBenson]

Oops..

...in my haste to see if the solenoids worked I FORGOT TO LOCK THE HUBS (!)

Duh...

Just took the...er... "lady" around the block, and she works great, all four feet.

Thanks to the fine folks at 3FE Group for directing my attention to the MOST OBVIOUS AND SIMPLE solution. I had worked myself into a frenzy thinking about $2500.00 T-case repair etc. etc...the typical nightmare scenario....

Hope I don't forget TO PUT GAS IN HER as well....(!)

regards from L.A.

Jesse

 

[Spook50]

Really? I engage 4WD high range at speeds between 20 and 30 mph. No trouble for 8 or 9 years of this...

Mine would always grind if I tried to engage it any faster than 15 MPH. I figure the less stress you're putting on the gears when you engage it, the better. That's why I always slow way down and make sure I'm driving straight before engaging 4WD.

 

[Texx]

Never a problem engaging mine at speed...

 

[Clack]

The only time this has happened to me was when I had a hub that wasn't engaging. Those who grind when going into 4 at speed should check to make sure their hubs are both engaging and make sure they don't get stuck w/o 4wd when the need it. (like I did D'oh!)

 

[3_puppies]

Oops..

...in my haste to see if the solenoids worked I FORGOT TO LOCK THE HUBS (!)

Duh...

Just took the...er... "lady" around the block, and she works great, all four feet.

Thanks to the fine folks at 3FE Group for directing my attention to the MOST OBVIOUS AND SIMPLE solution. I had worked myself into a frenzy thinking about $2500.00 T-case repair etc. etc...the typical nightmare scenario....

Hope I don't forget TO PUT GAS IN HER as well....(!)

regards from L.A.

Jesse

reading thru the posts that's what I thought, glad you found it. kinda eases the mind when it's a simple fix.

as long as you are not spinning the rear tires, and the hubs are locked, there should be no problem shifting in and out of 4HI. the front and rear shafts should be spinning at the same RPM.

I do it around here all winter long with all my rigs, leave the hubs locked and shift in and out of 4wd as needed.