Transmission or reducer issue in 1152A1

[Cybul]

Hi.
I have a problem with the gearbox or reducer in my 1152A1.
When I was accelerating the vehicle it suddenly disconnects my drive, it looks like I put the gear in N while driving. I have had the reducer set to H and D (in a circle), the situation has happened twice. The first on a tarmac road and the second time off-road.
When I stop the vehicle and add gas the rpm's increase but otherwise nothing happens, when I change gear to R and again to D, also nothing.
The solution to the problem is to switch off the vehicle, put it in N, change the reducer's gear to HL or L, put it back to H. Start the engine and change the gear to D or R. Then the vehicle run normally.
Also, I don't hear any rattling from the gearbox or reducer, no jerking when shifting gears.
Do you know what could be the problem?
I have owned the vehicle for a few days, the previous owner did not mention the problem, he said that maybe the cable needed to be tightened or loosened.

 

[Mogman]

Hi.
I have a problem with the gearbox or reducer in my 1152A1.
When I was accelerating the vehicle it suddenly disconnects my drive, it looks like I put the gear in N while driving. I have had the reducer set to H and D (in a circle), the situation has happened twice. The first on a tarmac road and the second time off-road.
When I stop the vehicle and add gas the revs increase but otherwise nothing happens, when I change gear to R and again to D, also nothing.
The solution to the problem is to switch off the vehicle, put it in N, change the gear to HL or L, put it back in H. Start the engine and change the gear to D or R. Then the vehicle starts normally.
Also, I don't hear any rattling from the gearbox or reducer, no jerking when shifting gears.
Do you know what could be the problem?
I have owned the vehicle for a few days, the previous owner did not mention the problem, he said that maybe the cable needed to be tightened or loosened.

Welcome to the SS forums!!
Sounds like your transfer case is jumping out of gear, the shifter does not have any detents so adjustment of the shift linkage is not likely the issue, unless the linkage is binding somehow.
This is a common issue with worn components in the T case, I would change the fluid paying attention to the magnetic drain plug.
But first check the level plug and make sure it is full but not over full, if over full this could be another issue entirely, if grossly under full then you have likely found the issue.

Also please download and read the TMs provided here on SS especially the .10 operators TM, it will save you money in the long run and help you use the correct terminology when describing a problem.

Also it will save you money to do a full service including ALL fluids and filters, no matter what the previous owner said, there are many examples here with expensive outcomes from not taking this advice.

This information is also in the TMs as there are items that need attention on a HMMWV that are not on most civy vehicles.

 

[Cybul]

Welcome to the SS forums!!
Sounds like your transfer case is jumping out of gear, the shifter does not have any detents so adjustment of the shift linkage is not likely the issue, unless the linkage is binding somehow.
This is a common issue with worn components in the T case, I would change the fluid paying attention to the magnetic drain plug.
But first check the level plug and make sure it is full but not over full, if over full this could be another issue entirely, if grossly under full then you have likely found the issue.

Also please download and read the TMs provided here on SS especially the .10 operators TM, it will save you money in the long run and help you use the correct terminology when describing a problem.

Also it will save you money to do a full service including ALL fluids and filters, no matter what the previous owner said, there are many examples here with expensive outcomes from not taking this advice.

This information is also in the TMs as there are items that need attention on a HMMWV that are not on most civy vehicles.

Thanks for fast answer.
I will check TM because it's a little bit hard to describe everything in proper words when I have to translate some specific words from Polish to English

 

[Cybul]

@Mogman I have checked few things


What has been verified:
- transfer case fluid level - is ok
- fluid colour and possible contamination - is ok

When the issue occurs:
It does not matter the speed, it does not matter whether you are driving in D or D-overdrive gear, it does not matter the road surface.
The problem occurs every time basically while driving.

It looks as if either the transfer case has come to N mode or the transmission has dropped to N while driving.

Video: Main issue

Then, after stopping the vehicle when I want to shift into P gear then a rattling sound is heard.

Video: Rattling
The rattling is more audible at the front of the vehicle than at the rear

After changing transmission shift lever to N and trying to shift the transfer case lever to HL or L it is impossible to move the lever.

Video: Transmission lever

HL or L can only be engaged when the vehicle is off, but as you can see in the video I also had a problem switching back to H.

The solution is to switch off the vehicle, set the transmission gear lever to N and move the transfer case lever to HL/L and back to H. Then start the vehicle, switch lever to D and you are good to go.

Video: Solution

Do you know what this might be?

 

[Thunderbirds]

Not to jump the gun since you asked Mogman, but you are going about shifting all wrong. I would beg you to read the Operators Manual. Here is the page talking about transfer case shifting...

 

[Mogman]

The "rattling" is the transmission output shaft turning when trying to put it in park because the TC is in neutral, stop doing that it can and will damage the parking pawl in the transmission.
The "rattling" when trying to shift the TC when the engine running is because you should NEVER shift the TC with the engine running this can and will damage the TC.
This would have been one of the "money saving" tips I talked about if you had read in the operators TM and why it is STRONGLY advised that every new HMMWV owner read this TM, you always turn off the motor before trying to shift the TC. with the transmission in neutral.

Nothing has changed since my first "guess" at what your problem is, the TC is shifting itself into neutral on its own (jumping out of gear), this is 95% going to be an mechanical issue in the TC case and the TC will have to be dismantled to find the issue.
The only other thing I would try is with the TC in H and the engine not running crawl under the truck and make sure the linkage going to the TC has some slack it it, to say you should be able to "wiggle" the linkage a little bit as it should not be in a bind.

I have no idea if you have any recourse against the former owner, but since it has done this right away the former owner knew of this issue, if he drove the truck.

 

[Mogman]

Not to jump the gun since you asked Mogman, but you are going about shifting all wrong. I would beg you to read the Operators Manual. Here is the page talking about transfer case shifting...

View attachment 938408

I was still typing my response when you posted, great catch!!!

 

[Cybul]

The "rattling" is the transmission output shaft turning when trying to put it in park because the TC is in neutral, stop doing that it can and will damage the parking pawl in the transmission.
The "rattling" when trying to shift the TC when the engine running is because you should NEVER shift the TC with the engine running this can and will damage the TC.
This would have been one of the "money saving" tips I talked about if you had read in the operators TM and why it is STRONGLY advised that every new HMMWV owner read this TM, you always turn off the motor before trying to shift the TC. with the transmission in neutral.

Nothing has changed since my first "guess" at what your problem is, the TC is shifting itself into neutral on its own (jumping out of gear), this is 95% going to be an mechanical issue in the TC case and the TC will have to be dismantled to find the issue.
The only other thing I would try is with the TC in H and the engine not running crawl under the truck and make sure the linkage going to the TC has some slack it it, to say you should be able to "wiggle" the linkage as iyt should not be in a bind.

I have no idea if you have any recourse against the former owner, but since it has done this right away the former owner knew of this issue, if he drove the truck.

Ok so part about rattling is clear and this is my oversight.

The former owner had certainly owned the vehicle for more than six months. He has several hmmwvs and other military vehicles for sale and also repairs them He claimed it was fully operational, having changed filters and all fluids.
I asked him if there was anything to be done to the vehicle and apart from a few fiddly things e.g. one windscreen wiper not working etc, everything was supposed to be ok.
During the test drive at his place in the field the problem did not occur, but after transporting it on a trailer for over 300 miles during the first and every subsequent drive at my place there is already what I described.
I have legal remedies to demand repair, price reduction or cancellation of the contract.

 

[Mogman]

I do not see any way that shipping could have done this damage, although one should always transport a vehicle in neutral so the parking pawl in the transmission does not get damaged by the truck rocking slightly forward and aft, but that should not affect the TC.

 

[Cybul]

This vehicle is in Europe since Feb 2024.
And was in use for several months by the previous owner, so there's no way he didn't know about it.

 

[Retiredwarhorses]

Make sure the detent spring and plunger are still present, I’ve had more than a few trucks from the auction missing these parts because they drained the Tcase fluid as part of Demil and transport from overseas via the detent plug…some are missing the plunger, others missing both the spring and plunger.

 

[Retiredwarhorses]

This vehicle is in Europe since Feb 2024.
And was in use for several months by the previous owner, so there's no way he didn't know about it.

A slipping transfer case isn’t the end of the world, some of your statements are assumptions on your part, but I’d rather not go into that, I’ve sold many many trucks into the EU, I can first hand tell you how they are broken when they arrive because of boneheads at the transport companies and the ports, once that truck leaves my shop and it’s gone for 2-3 month on a ship, it’s out of my hands.but if you are already at the “legal” remedy's as you say….you have made up your mind it was done with malice.

 

[Cybul]

Make sure the detent spring and plunger are still present, I’ve had more than a few trucks from the auction missing these parts because they drained the Tcase fluid as part of Demil and transport from overseas via the detent plug…some are missing the plunger, others missing both the spring and plunger.

Hi. Thanks for you answer.
Could you tell me where I should look for these two parts (detend spring and plunger)?

 

[Retiredwarhorses]

Item 29 and 30

 

[Retiredwarhorses]

Understand, in order to check, you will need to remove item 27, that will drain the Tcase of its fluid, you will need to refill the Tcase after checking That the spring and detent are actually present.

 

[Mogman]

Make sure the detent spring and plunger are still present, I’ve had more than a few trucks from the auction missing these parts because they drained the Tcase fluid as part of Demil and transport from overseas via the detent plug…some are missing the plunger, others missing both the spring and plunger.

AWESOME! I actually had one that was missing the spring and plunger, they obviously thought that was the way to drain the fluid and then just left the parts out and re-installed the plug, I forgot all about that
Great catch!!
I blame CRS

 

[Mogman]

It was obvious as you could feel the lack of detents as you shifted the TC
I hope that is the issue as that is an easy fix!! and I assume they would drain the fluids when it was shipped to EU

 

[Cybul]

Yes. It was "empty" without any fluids.
Will check it.

BTW: I need bigger garage

 

[Retiredwarhorses]

Yes. It was "empty" without any fluids.
Will check it.

BTW: I need bigger garage

View attachment 938417

well, it shouldn’t have been empty of fluids from the “seller”, the military drains the fluids as part of the shipping process, one would hope before anyone started the truck and drove it, they would have checked ALL fluid levels prior to any starting and driving.
i just had a truck into the shop, purchased 3yrs ago…customer drove once a week, needed a new injection pump…a cursory inspection revealed NO fluid in the differentials, geared hubs or transfer case…

 

[Cybul]

Item 29 and 30View attachment 938416

Ok....
I don't see part 28, but...
#30 was inserted inversely directly into the screw #27 and the spring #29 into it.
Now I can't remove spring from TC, something is blocking inside.