transfer case repair/swap help (1 Viewer)

Joined
May 11, 2005
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333
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OKLAHOMA cITY
 
 
 
Howdy all, haven't been here in a while, and I need your help.

I think the transfer case in my 91' has died. It has been clunking very hard when I accelerate. And when I put it into park, it rolls at least a foot or more before it stops. A mechanic told me he thought there was excessive play in the transfer case.
Yesterday, my wife said while accelerating, the tranny sounded like it was grinding gears before it finally seemed to catch and drive away.
Today, while accelerating, it stopped working, when she hit the gas, it didn't go anywhere, and it still rolls in park.
So, is there a way to repair these things? do I need to swap the whole tranny, or can I just swap the transfer case? Where can I get a transfer case?
Please help, the truck was for sale until this happened (didn't want to sell it anyway).

Thanks!
Kent
 
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May 11, 2005
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333
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OKLAHOMA cITY
 
 
 
not positive, but I have ha some problems with the transfer case, so I assumed it was still that. planning on looking more closely at it in the morn.
 
Joined
Aug 9, 2003
Messages
9,015
 
 
 
Josh has it. Not going to be the center differential (nee transfer case). Take the center cap off and the little silver dollar size grease cup and see the axle shaft is splined and engages there. Do it on both sides. Clean so you can put matching paint dots (or some other strategy - tape?) to see if the shaft moves relative to the drive plate it engages. Go make it do the sound and stop to find out you're lucky and you only need new drive plates 'cause those marks aren't gonna line up anymore indicating the splines are worn. Order new ones from Cdan, install them in 30 minutes (can even leave the wheels on) and toast Mud for saving you some Irish Green...... Confident - me? Heh.

DougM
 
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333
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Actually, I think the problem may only be a a badly adjusted shifter arm for the transfer case, anyone know how to adjust it?
Thanks
 
Joined
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So is there a way to adjust the shifter lever for the transfer case?
Need to fix today if I can,
Thanks
Kent
 
Joined
Aug 9, 2003
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I'd be looking at what the body lift did to the shifter lever's adjustment and that can only be done by the person lookin' at it - which is you. 99.9% chance lifting the body caused the problem and none of us have any idea what the person who 'did' the lift actually did.

DougM
 
Joined
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OKLAHOMA cITY
 
 
 
I'd be looking at what the body lift did to the shifter lever's adjustment and that can only be done by the person lookin' at it - which is you. 99.9% chance lifting the body caused the problem and none of us have any idea what the person who 'did' the lift actually did.

DougM
I'm not ruling out the body lift, but it has been on the truck for over 10 years. I looked at the lever under the truck, and it doesn't look like its changed adjustment in about as many years.
There is a chance that the gears are worn to the point that they are not letting the truck cant stay in HI.
Are there any transfer cases what I can swap to the original tranny?

Thanks
Kent
 
Joined
Aug 9, 2003
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I'm not sure you're heading in the right direction here is all. It may be constructive to essentially start over in terms of describing the symptoms. The center diff on your vehicle is industrial grade - 100% gear driven, etc. The 91 engine is very low in power compared to later models, which makes it even more bulletproof. With "something" slipping I just don't see the center diff slipping though something made you focus on the center diff shift lever and I don't know what.

DougM
 
Joined
May 11, 2005
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OKLAHOMA cITY
 
 
 
I'm not sure you're heading in the right direction here is all. It may be constructive to essentially start over in terms of describing the symptoms. The center diff on your vehicle is industrial grade - 100% gear driven, etc. The 91 engine is very low in power compared to later models, which makes it even more bulletproof. With "something" slipping I just don't see the center diff slipping though something made you focus on the center diff shift lever and I don't know what.

DougM
Thanks for the input. I didn't say anything about the center differential. I am talking about the transfer case only and the gears in it. Someone else brought up the center diff.
the truck wont drive in HI gear on the transfer case. When it was driving, there was a big clunk when you put it into drive or reverse, and it would roll almost a foot when I put it into park.
A mechanic told me that there was almost a full turn of play in the driveshafts when the car is in park.
The other day, the truck just stopped moving when the truck was in drive. thee was a light sound of grinding in the tranny.
The truck will drive perfectly when i shift into LO. there is not even any play or "clunk" when in LO.
Drove truck home in LO, and drove fine. When I was about 2 blocks from my house, I tried shifting into HI again, and the truck drove fine again for about a block, then it seemed to "slip" out of HI and there was the light grinding again.

SO:
It is either slipping out of HI, (not very likely)

OR:
The HI gears are either broken or worn to the point of not being able to keep it in gear. (more likely given the high miles and previous clunking)

That is my thought. Any Others?

Thanks
Kent
 
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Kent,

Just to clarify, you don't have a transfer case which is a gearset that can transfer power to either just the rear wheels, or all 4 wheels. You have a center differential which sends power full time to the output shafts. That's part of the confusion.

Exactly what you described is 100% compatible with Posts #4/#5. I had not gotten around to asking if it drives fine in low range which you now volunteered. You have a stripped drive flange or both are trashed. Odds of it being a ruined transfer case are in the 2% range. This is great news.

Do us both a favor and remove the grease cups (5 minutes with a thin screwdriver and hammer to tap) and do the paint or tape test.

DougM
 
Joined
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Messages
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OKLAHOMA cITY
 
 
 
Kent,

Just to clarify, you don't have a transfer case which is a gearset that can transfer power to either just the rear wheels, or all 4 wheels. You have a center differential which sends power full time to the output shafts. That's part of the confusion.

Exactly what you described is 100% compatible with Posts #4/#5. I had not gotten around to asking if it drives fine in low range which you now volunteered. You have a stripped drive flange or both are trashed. Odds of it being a ruined transfer case are in the 2% range. This is great news.

Do us both a favor and remove the grease cups (5 minutes with a thin screwdriver and hammer to tap) and do the paint or tape test.

DougM
I see what you mean about the center diff. I know this is my confusion here, but I don't understand how if it is the drive flange that is stripped (in the axles, right?) how it would drive in LO but not HI. I will try the suggestions, I am just trying to understand the problem.
It's pretty obvious by my lack of knowledge on the center diff, that I am having knowledge problems here.

Plus, can you be more descriptive on how to check the splines? (like what little metal cap you are talking about? lol)

Thanks for all the help, and the schooling!:) You guys are a GREAT help!
 

cpg

Joined
Dec 27, 2004
Messages
677
Location
Livermore , Ca.
 
 
 
the truck wont drive in HI gear on the transfer case. When it was driving, there was a big clunk when you put it into drive or reverse, and it would roll almost a foot when I put it into park.
A mechanic told me that there was almost a full turn of play in the driveshafts when the car is in park.
The other day, the truck just stopped moving when the truck was in drive. thee was a light sound of grinding in the tranny.
The truck will drive perfectly when i shift into LO. there is not even any play or "clunk" when in LO.
Drove truck home in LO, and drove fine. When I was about 2 blocks from my house, I tried shifting into HI again, and the truck drove fine again for about a block, then it seemed to "slip" out of HI and there was the light grinding again.

SO:
It is either slipping out of HI, (not very likely)

OR:
The HI gears are either broken or worn to the point of not being able to keep it in gear. (more likely given the high miles and previous clunking)

That is my thought. Any Others?

Thanks
Kent
Sounds like the High range Idler gear and/or the High range half
of the Clutch sleeve in the tranfer case are stripped. If it seems to drive fine in Low I dont think it would be stripped drive flanges on the axle shafts.
 
Joined
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286
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Decatur,AL
 
 
Please correct if I am wrong.
The center diff works like the diff in the axles, sends power to the wheels that slip not the ones that grip (unless you lock the diff). The center diff sends power to the axle that slips (maybe with stripped splines) and not the one that grips. When you put it in low it locks the center diff and sends power to both front and rear axles equally.
 
Joined
Feb 20, 2003
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709
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Purdue Land
 
 
 
Please correct if I am wrong.
The center diff works like the diff in the axles, sends power to the wheels that slip not the ones that grip (unless you lock the diff). The center diff sends power to the axle that slips (maybe with stripped splines) and not the one that grips. When you put it in low it locks the center diff and sends power to both front and rear axles equally.
Bingo!


Could the OP not just hit the center diff lock switch to test this theory? Or was that not available in 1991?
 
Joined
Jan 26, 2009
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Southern WI
JD(Josh and Doug) are on the money. It could be more than one or the other drive flanges though, but thats the easiest and first thing that should be checked.

I broke my passenger side birf/axle joint 2 years ago. It would grind in HI but when i locked the center diff, OR PUT IT IN LOW, it would drive. Its hard to explain why, and i try to picture it over and over again in my head, but thats how it works.

If you broke a drive flange, you would experience the exact symptoms you are showing. I drove my vehicle for almost two years with the center diff locked before i fixed it. You are essential driving it in two wheel drive, the front doen't spin, only the back, even though your in low or the center diff is locked.

The only reason i didn't fix it right away was to properly test it in its 2 wheel drive form for a few years. I liked it so much i plan on doing the conversion.
 
Joined
Mar 16, 2009
Messages
1
My tranfercase went out too when i opened it today the driive gear was fully sheered. My tranny when putting into park would grind, r,d,1,2 no movement.
 
Joined
Aug 9, 2003
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9,015
 
 
 
mmm's got it. In low range the center differential is locked and your truck will go forward without the axle splines "slipping" and making that noise (though you might hear a single pop or two on a turn if they're badly stripped). In high range, when the spline of one front wheel slips, its axle shaft spins faster briefly and that axle will get more torque as a result - just as if that tire slipped on ice. It is a trait of open differentials that the slipping tire/axle gets more torque and the reason a 2WD car can simply sit there with one wheel spinning on ice and go nowhere. I don't want to turn this into a lesson on differentials so I won't belabor it.

Your factory wheels have a center cap. Pry one off the front wheel with a screwdriver and you'll find the circular drive plate with bolts around its perimeter. (You don't need to take the wheel off, or anything - just walk right up to it in the driveway and pry off a center cap) In the center is a removable cap like a silver dollar sized metal cooking pot. This can be cranky to pry off, but use a very slim screwdriver and patiently tap around it until you get it moving. Don't just pry at one spot or you'll jam it - go around and around. It's OK to damage the lip a bit from the prying - once reinstalled you simply tap these edges back down.

Anyhow, get the cap off and now once you wipe away the grease you'll be looking at the actual tip of your axle which goes all the way into the differential and this shaft literally drives the drive plate - it's what powers this wheel. Look closely and you'll see the drive shaft and drive plate mate with splines. Ignorant mechanics forget to put grease in these splines and they generate metal dust and wear out the splines with the drive plate being softer and luckily the part that must be replaced.

To see if yours are slipping (get both exposed and cleaned with a rag with solvent on it) put a dab from a permanent marker, nail polish, a piece of tape or whatever it takes on the shaft's circular end and a matching mark next to it on the drive plate such that if it slips even a single spline you can see that it did. Once it slips, obviously the two marks won't be in alignment.

Put the truck in high range and try to drive off. Once it makes the grinding sound stop and get out and see if the marks still line up. Yes? You're hosed and something else is broken. No? You're in luck and the fix is both cheap and fast.

DougM
 

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