Blown Transfer Case? Actually a blown front diff (1 Viewer)

[drjman]

I got stuck doing some wheeling a couple days ago and the truck developed that grinding in high gear and once i was winched out I could only drive down the mountain in 4Lo. Had the LX towed to my mechanic who just let me know my transfer case is blown up (bearings everywhere inside, etc). He could only source a new case from a dealer (no one would rebuild it). Quoted $4800. There is no way I can afford that....

I found a couple used transfer cases in junk yards, but the closest is TX (i'm in CA). Even so, that looks like a big job to replace.

Does anyone have any ideas on this one? Am I screwed?

 

[Biga27110]

I would expect there to be a bunch of parts available for our trucks. Hmmm.

 

[3_puppies]

you should be able to source a good used 1 for between $700-950
a guy here in MT picked one up for $900 with a 3 month warranty.
I don't think it was that hard to change out.

 

[drjman]

I just spoke with a Lexus mechanic that is a little far away (I know people who have taken their LX's with great success). My mechanic said he looked into the transfer case and saw bearings, etc everywhere. This Lexus mech said that's not even possible to look inside. So I'm going to get a second opinion from him.

Based on the sound and being able to drive it in 4lo and locked, I figured it was the drive flange splines being stripped and hopefully it was cheap and that would do it.

 

[jLB]

Before you pull the trigger on a transfer case...

Usually when someone posts about a blown/broken transfer case, it isn't the transfer case at all. It's usually an issue with the "front axle to drive plate interface". Usually when one has this issue the truck will move fine with the center diff locked, and make nasty grinding noises when the center diff is not locked. If the problem is with the 98 LX in your signature, and my memory is correct, the 98-99 year models automatically locked the center diff when they were shifted to 4-low (2000-2007 models require you to manually lock the center diff with a dash switch). I'd check this before I purchased a transfer case.

 

[drjman]

you should be able to source a good used 1 for between $700-950
a guy here in MT picked one up for $900 with a 3 month warranty.
I don't think it was that hard to change out.

I definitely saw some junk yard ones for that price range or even cheaper.

 

[drjman]

Before you pull the trigger on a transfer case...

Usually when someone posts about a blown/broken transfer case, it isn't the transfer case at all. It's usually an issue with the "front axle to drive plate interface". Usually when one has this issue the truck will move fine with the center diff locked, and make nasty grinding noises when the center diff is not locked. If the problem is with the 98 LX in your signature, and my memory is correct, the 98-99 year models automatically locked the center diff when they were shifted to 4-low (2000-2007 models require you to manually lock the center diff with a dash switch). I'd check this before I purchased a transfer case.

EXACTLY. I found that in my research last night and specifically asked my mech to check the "flange" or plate you're talking about.

I would think if the transfer case was completely shot, that it shouldn't drive in 4Lo either....

 

[3_puppies]

I'll try and find the thread on the guy in MT

 

[drjman]

I'm having a hard time understanding how the transfer case is supposed to work. Mainly, how could it still work in 4Lo (diff locked) and not in 4H?

I did not try to run 4H with the center locked. I'm wondering if that would make it drivable. In that case, would disconnecting the front drive shaft and running 4H just be 2WD at the rear and isolate the issue with the front?

 

[jLB]

Probably not the best explanation, but I'll give it a try:

With an "open diff" the driveline power follows the path of least resistance. If you've got a bad axle/drive plate/front differential, the driveline power will spin the broken part(s) and not move the vehicle.

If you "lock" the center diff, the front and rear driveshafts turn at equal speeds, it prevents all of the power from "leaking out" the broken part, and you move.

 

[drjman]

Probably not the best explanation, but I'll give it a try:

With an "open diff" the driveline power follows the path of least resistance. If you've got a bad axle/drive plate/front differential, the driveline power will spin the broken part(s) and not move the vehicle.

If you "lock" the center diff, the front and rear driveshafts turn at equal speeds, it prevents all of the power from "leaking out" the broken part, and you move.

I think that makes sense.

When I was in 4Lo and locked, shouldn't there still be some grinding noise coming from the front? It drove normally in 4Lo and diff locked. I think that's what's confusing me.

 

[jLB]

In 4-Low (locked), going in a mostly straight line, I would think that the drive plate/axle grinding might be minimized, because the driveline is spinning at about the same speed as the wheels.

 

[drjman]

In 4-Low (locked), going in a mostly straight line, I would think that the drive plate/axle grinding might be minimized, because the driveline is spinning at about the same speed as the wheels.

I apologize for not being clear in the last post....There was NO grinding noise at all when in 4Lo and locked. Even had to make a few wide turns to get to the gas station and no grinding noises.

 

[jLB]

Maybe my word choice was not the best, but just because there is not a detectable "grinding noise" in 4-Low, it does not mean that there's absolutely no "slippage" occurring at the drive plate.

It should be pretty easy to verify the issue by "popping the grease caps" on the front hubs, and taking a look.

Another possible alternative is that you may have "blown" the front differential, which isn't terribly uncommon on the 98-99 models with their 2 pinion front differentials.

 

[drjman]

Maybe my word choice was not the best, but just because there is not a detectable "grinding noise" in 4-Low, it does not mean that there's absolutely no "slippage" occurring at the drive plate.

It should be pretty easy to verify the issue by "popping the grease caps" on the front hubs, and taking a look.

Another possible alternative is that you may have "blown" the front differential, which isn't terribly uncommon on the 98-99 models with their 2 pinion front differentials.

Truck is currently at the shop. I don't want to use another AAA tow if I don't have to. I'm exploring ways to get it home (5 miles, paved). Once I get it back, I'll definitely pop off the caps and check the splines.

My latest research is making me think about the front diff being blown since mine is a 1998. That would certainly be a cheaper thing to fix than a transfer case.

 

[Biga27110]

From your symptoms they sound a lot like front diff being busted

 

[slacker24-7]

I seriously doubt the tcase is blown, several things in the driveline should go before the case if it was bound up or something while stuck. Do as others have suggested in checking that drive flange , front axle and possibly front diff, did you have to engage the CDL to drive it ?

 

[gatormark91]

I got stuck doing some wheeling a couple days ago and the truck developed that grinding in high gear and once i was winched out I could only drive down the mountain in 4Lo. Had the LX towed to my mechanic who just let me know my transfer case is blown up (bearings everywhere inside, etc). He could only source a new case from a dealer (no one would rebuild it). Quoted $4800. There is no way I can afford that....

I found a couple used transfer cases in junk yards, but the closest is TX (i'm in CA). Even so, that looks like a big job to replace.

Does anyone have any ideas on this one? Am I screwed?

A. NEVER go back to that mechanic
B. If the diff was grenaded, it would probably still be noisy, because ... busted gears still turn even with diff lock sending power to the rear wheels, bits of teeth in the housing, etc... If you stripped a drive flange, it won't make any noise when the truck is moving with the diff lock on.

 

[3_puppies]

here's the thread I was thinking about

Blew up something!

During some night time snow wheeling over Judith Peak in Montana. I broke something while going through deep snow drifts, waist deep snow, 200 point turn around or pulling the idiots out of the ditch in a car (because driving late night with no; gear, clothes, cell services, with the intent to...

forum.ih8mud.com

 

[drjman]

Thanks everyone for the suggestions and help. I'm trying to figure out a time I can go over there and possibly get it home in 4h and locked. That way i can examine the flanges, diff, etc. I'll keep updating.