Clunking on acceleration

westyss

Explorer
Thanks for the suggestions everyone!

Well it’s not good! The truck is at Kearny Mesa Truck Centre and the transmissions out, so far the output shaft is bad and a cluster of gears but not all certain yet. It just got pulled out yesterday afternoon.
Owen, metal chunks on the magnet, so that signaled a definite tear down.

We had a hard time finding a place to stay as we had arrived on Thursday and everything was booked and triple priced! We camped on the street until Monday and moved into an Air BNB that we have for four nights.
Hopping we can gets the appropriate parts.
 

SkiFreak

Crazy Person
Well, that sux Yves!
Hopefully you can get all of the required parts in a timely manner, and that the repair does not cost a fortune.
When you have all of the details, please let us know what happened and if they know, why they think it happened.
 

westyss

Explorer
They can get the parts ok by the looks of things, the output shaft is damaged from the bearing imploding which galled the shaft. While it’s all apart all bearings,seals,clutch stuff including the slave cylinder will be replaced etc.
It will cost a bundle! I haven’t really heard much of any other trucks having such issues at least on here so something to look forward to!

So far simple wear and tear seems to be the cause, not sure about the one bearing though but no “smoking gun”.
 

SkiFreak

Crazy Person
Will you be replacing the syncros as well?
From what I have seen over the years, many people have had issues with crunching between 3rd and 4th, so if not all, those two syncros might be worth replacing while you're at it.
 

yabanja

Explorer
Late to the party here. Sorry to hear about your misfortune!! Mexico would be a much nicer place to be than a shop!! Transmission failures are common. I know of at least four others. I am running redline MTF as I have said elsewhere on this forum. Strongly recommend it. Good luck with getting back to your travels soon.

Take care,

Allan and Sakshi
 

ThundahBeagle

Well-known member
Sorry to hear that!

I do feel you pain, though. Had a "catastrophic" failure of transmission in my 2014 GMC Sierra this past spring at 180,000 miles, but I was only a mile from home. Well out of warranty, GM said they would just replace it for $8,000. I balked.

Eventually I found a small, local transmission shop that gets Lakeview (?) transmissions built out of Michigan or Ohio or something, where they improve with better parts on all of the typical GM points of failure. Got it installed for about $5,200. So far so good.

I hope your story ends well.
 

westyss

Explorer
Once they got the tranny out and opened up I decided to get it all done, as in all new syncros, all internal bearings, which I think there are six of them and the gears on the main shaft as well.
Gears on the countershaft are ok.
The splines of the output shaft were worn away to nubby mounds so ended up getting into the transfer case receiving end which didn’t look as bad but had worn enough to warrant replacing also, so while in there the bearings are being replaced, no point not doing it all, tear down is costly and I certainly don’t want to be in the middle of nowhere and have any other issues.
The output shaft seems like a bad design for wear as there is no way to get any grease in there other than on the initial mating of the tranny and transfer case.
Thanks for the condolences, I think with several years of therapy I will be OK!
 

SkiFreak

Crazy Person
The output shaft seems like a bad design for wear as there is no way to get any grease in there other than on the initial mating of the tranny and transfer case.
Is there any possibility of adding a grease point while the box is apart?

I modified a part of my own gearbox, that being the bush for the gate selector shaft.
The OEM bush was, in my opinion, severely lacking in its functionality, so I machined out the housing and replaced the small split white metal bush with a phosphor bronze bush which now gives more than double the support of the shaft and far less play. The change between 3rd and 4th is now far more positive, which I noticed immediately after making the modification. I am a Fitter/Machinist by trade, so this was a simple task for me.

While at it, I also replaced the poorly designed gearbox and transfer case breathers, which is a modification I would recommend to anyone, as the OEM breathers are rubbish.

 

Aussie Iron

Explorer
If your box is the same as the earlier boxes which I believe more or less it is. That rear gearbox bearing has no problem getting lubricated by splash feed. It is not supposed to be a sealed bearing. It is lubricated from the gearbox side as the seal is in the transfer case. Only know of one gearbox output shaft being worn and repaired. That gear in the transfer case (on the gearbox output shaft) needs to be a firm push fit and well tensioned. I generally have to fit those gears with a puller.

" Anyway time to up grade you gearbox and transfer case. Add syncros to first gear (yes, you will get syncro in reverse as well) . High speed (high range) transfer case gears. You will end up with lower low range as well "

Dan.
 

westyss

Explorer
The output from tranny into transfer case was very worn! Those splines were small pyramid nubs that were so worn out I want to say they were the cause of the clunking but I’m not certain.
I am keeping every component removed from the whole works and I will try to upload some pictures of those splines. We did insert the main output shaft onto the female side of the transfer case and obviously was very sloppy, not at all a tight fit, I can’t say for sure that the transfer case side of it was worn as bad as the tranny output shaft was, maybe some pictures will tell the tale?
 

Aussie Iron

Explorer
The wear on that spline will certainly give you a bad clunking sound on acceleration and deceleration. It will resonate through the gearbox and transfer case and will sound like it is all coming apart. It will also throw everything out of line in the rear gearbox bearing and you will get abnormal wear in the bearing.

Pictures will certainly be nice to see. I mean not good but interesting.

Dan.
 

westyss

Explorer
Thanks Dan,
You were also saying something about up grading the gearbox, I’m not aware of any up grade items at least not here in North America, here we have a difficult time just getting parts! I would have liked to get a bit different gearing and newer less fragile syncros but right now I am happy to just get parts and be on my way.
If I was home and could take my time I would look and see if purchasing a whole transmission would be possible even from Australia!
 

Aussie Iron

Explorer
Thanks Dan,
You were also saying something about up grading the gearbox, I’m not aware of any up grade items at least not here in North America, here we have a difficult time just getting parts! I would have liked to get a bit different gearing and newer less fragile syncros but right now I am happy to just get parts and be on my way.
If I was home and could take my time I would look and see if purchasing a whole transmission would be possible even from Australia!
I know Syncros can be fitted into our boxes (over here) to be able to have syncro on 1st gear. Certainly would be handy when 4WDing in the rough. The hub (1st/reverse) that is in there is slotted for them to fit in there. So yes, you end up with syncro for reverse as well. When I had a customers gearbox apart, I had a look and sycro rings and clips from 2nd/3rd gears were what would fit.
Only parts syncros that I know of are all from Mitsubishi Parts.
As far as different gearing - that hasn't been heard of either. The only way gearing may possibly be changed is to try and fit "Rosa Bus" gearbox which is six speed but the top five gear spacing is not a lot different. But if my memory is correct, it has another gear lower than 1st in our 5 speeds.
I know I went into this all before I had new transfer gears made. Trying to get our road speed up (engine revs down).

Dan.
 

westyss

Explorer
Couple of pics, one on the right is what I’m calling the output shaft, left one is just a comparison of what it should look like mostly, it is the shaft from the transfer case.
FF37E298-4393-4D92-999C-F187370AA896.jpeg5D1E1FF8-E7DF-4953-87A4-0E29A90D63F7.jpeg
 

Forum statistics

Threads
186,274
Messages
2,883,978
Members
226,151
Latest member
Dgollman
Top