Transfer case rebuild (1 Viewer)

[Digger276]

OK Pros,
Going to rebuild the transfer case and put it the part time 4wd in my 91. I saw the man-a-fre part time kit and like it, (thanks to this site), I am going to rebuild hte transfer case while I am at it and was wondering if anyone had any tips or advice that they ran into.

My 91 has 144,500 on it. I am trying to take some of the slug out of it with going to part time. It is real falt here so I really don't need full -time 4wd. Any suggestions with that also.

Thanks Guys

Cris

 

[IdahoDoug]

Cris,

Here's my input and you're not gonna like it.

At 144k your 91s center differential (what you're incorrectly calling a transfer case) is just broken in and not in need of a rebuild unless it's been abused (unlikely).

If your motive is to make the truck faster, you bought the wrong truck. Sell it and get something that is faster. Way cheaper and way less trouble and you'll likely also find a vehicle that gets 25% better fuel economy in the process.

If your motive is to make the truck faster, there are way better ways to spend your money than this. After all that mucking around and turning it into a part time rig, the truck will be a bit heavier due to the added parts. And you'll likely save perhaps 10hp from reducing the rotating mass. So it will feel - well, it will feel pretty much like the same truck in terms of being a slug.

Finally, I have read the sentance 5 times trying to figure out what "real falt" is like and how that makes full time 4WD unneeded. I ask because I myself have been stuck axle deep in falt and it's great to have the full time to get out....

DougM

 

[LandCruiserPhil]

Auh....What is "falt"?

 

[lagwagon]

You probably won't get much extra fuel mileage. That said I know someone selling a part-time kit and I have a couple of transfercases for sale if you want to keep it cruisin while you build it

 

[landtank]

Falt = Flat

 

[cruiserdan]

80 series transfer cases (containing a center differential Doug ) are very durable and I know personaly of ony 3 failures (2 of them being Landtoy's bad luck :-\ ). They leak on a rare occasion and that is about it. My experience with failures is not all-inclusive and others may know of more failures but I do not recall any mention of them on this board or the old SOr board (other than Kurt's saga).
If you have your heart set on a P/T conversion, Christo's site has a nice write-up on an install. I would inspect it first before I started throwing new parts at it.


D-

 

[Digger276]

Thanks Guys, yes falt = flat, my mistake. Only sand here for me, beach use occasionally. Reference to the hp ?. I know in older chevy's each drivebelt uses approx 20 hp, so I believe that adding this p/t kit may increase more than 10hp. As for rebuilding, I have a very solid clunk when putting it into drive. I watched underneath when someone else went from drive to reverse and the play all came from the transfer case. What does it need instead of a rebuild then to stop this? It doesn't sound healthy. Thanks to all. Does anybody know anyone that has installed the p/t and its results?

 

[Jesse]

>>I know in older chevy's each drivebelt uses approx 20 hp

That sounds hard to believe because most of them had three belts = 60 hp.
Maybe i am wrong though.

Jesse

 

[Digger276]

True but older engines also had not so easy moving, pumps and a/c compressors as today so I am not sure of the numbers now.

 

[xl715]

So let me get this right, you have a clunk goming from ?? But instead of figuring out what is wrong you just want to through the conversion on it?
Theres a real easy way to find out the difference of doing the conversion without doing it, remove your front drive line and lock the center diff in high range and go for a drive. I did this a one point when I was contemplating doing the conversion also, however the truck just doesn't seem right in two wheel drive.
Also, in my experience especially in sand, all wheel drive, not true 4 wheel drive gets you further most of the time. If you do the conversion you lose all wheel drive, right?

 

[Digger276]

No the clunking is coming from the transfer case, if I am going to rebuild it, i thought of putting that kit in and it would be the same but you would have to get out and turn the front hubs to lock the wheels into 4wd. I am not the add something to solve a problem guy, I am fixing the problem and thinking of adding while I have it all out. Does anyone know anybody who has done this? Thanks to all

 

[Beowulf]

Chris,
I think if you'll do some research here, the SOR archives (see link above), and other places like 80sCool, you'll find that many of us experience the joy of the 80 series clunk. Robbie posted a good explanation of all the rotating bits and how they accumulate driveline slack.

There are pics of the VC transfer case and center diff in some of Kurt's posts (landtoy80.) I think you might see a bearing problem at 145k but "slack" doesn't seem likely unless there's been some significant gear wear. At 145k miles that is unlikely (but not impossible). I'm right behind you at 135k miles, have the occasional clunk, and there is no way I would tear into the transfer case unless I was convinced there was a problem.

Read XL715's post again. Your vehicle was designed as full-time 4WD. It will drive differently as a PT rig. Poverty pack vehicles in OZ were PT rigs as were all cruisers prior to the 80 series so it's not unreasonable to think this might be something worth doing. You'll likely save some MPG and you'll likely "feel" more peppy. You'll likely spend big bucks getting there and Doug's advice about getting more HP is worth thinking about.

Good luck and keep us posted if you choose to go PT.

-B-

 

[landtoy80]

As for bad t-cases, it is me and two others. I don't think the others are on the board anymore.

I have been obsessing about what went wrong with mine and the others t-case.
I thought it was the VC (viscous coupler/control coupling) but now think it was a bad/hot bearing. The VC locks up when it gets hot.
I thought it was a bad rear output bearing. I got one and was going to replace it but after talking to a tranny shop he said that it couldn't be that. I went with a new t-case instead. I was, at that time sure it was the VC that was the problem. With much thought I wish I would of replaced the rear output bearing.

With the t-case that doesn't have a VC, one wouldn't know if their bearings are going bad/hot unless they got under and checked it after driving at hwy speed. They would have to wait till they could hear the bearing noise to know if they are going bad. Then at that point there could be damage to other parts of the t-case.

Looking at my old t-case,with 208k mi, I didn't see any wear or bad bearing (no bluing).
The t-case did get very very hot so I don't know if I can reuse the VC but the rest of the t-case could be rebuilt.

One good thing about the HF2AV (with the VC) is that the VC will let us know when the bearing are going bad before there is damage to the rest of the t-case.
The VC will lock up if your t-case gets to hot.
To test; drive at hwy speed on a hot day and then, in a parking lot, drive in a circle and see if it feels like the center diff is locked.

Note:
This is all theory at this time as I still need to find out how the VC is really suppose to work.

 

[Digger276]

-B-
Thanks for the post, I have been 4x4ing for some time, 79 F150, a couple Jeeps, Ford Explorer sport (the worst handeling) and know the handeling issues from the switch. I don't think the change will be so drastic but so many people have a negative feeling about this, I would like to talk to someone who has done it. I also will be doing the work with a friend at his shop. I do most of my work, rebuilding and such just need his shop for the lift, so the kit about 500, the rebuild kit about 200 and give my friend 100 for the help and bamm we're in. And I got this one for 2,000, put 400 in parts, and 150 in maintence, so I will still be under the value of the vehicle. Thanks again for the nice post.
C

 

[IdahoDoug]

Cris,

I applaud anyone wanting to push the envelope and willing to try dramatic change, however I sincerely think you're considering this change without completely thinking it through.

What did you see under the truck that tells you it's slack in the center diff? What is normal for this diff? I ask this because the center diff is an incredibly overbuilt component and the engine you have simply cannot stress it much. I suspect you're simply seeing normal wear rather than any issue requiring intervention.

Ironically, if correct that you have a failing ctr diff, your analysis would indicate repair to the ctr diff is called for. Instead, you're proposing spending money elsewhere. And should you need the failing center diff in the future (stuck in sand, manually shifting to 4WD), it's going to fail under stress. But you'll have an excellent PT conversion shift kit onboard to talk to the tow truck driver about as he pulls you into town for $150.

So it just seems misplaced to me. You either have a damaged center diff (doubt it and you haven't shown this) that should be repaired, or your center diff is fine and you simply want to have a unique vehicle converted to PT. I suspect the latter and so do others here.

I already covered the power increase. I sense that you're getting a bit frustrated that there aren't a lot of folks saying "Yeah man - welcome aboard and that's a cool alteration that is exactly what we would do." Don't let that bug you. Do what you want with the truck and enjoy it.

DougM

 

[PHAEDRUS]

Guys big point being missed here is that this is a 91 so no vc to be going south on this truck. these are spider gears nothing more in the center of the 91-92's.
I believe there is a thread about dropping the front drive lines on a later (vc) equipped truck by robbie form slee. Hell yeah he will have some handling issues with it but nothing that you couldn't get used to. Cris I recomend you call slee and talk to robbie about how his is handling now without the front line in.
My personal opinion is that the kit is overpriced. I am still fighting with my center diff on my 92 and have not had time to tear into it and play but (putting the asbestos suit on now) I was seiously considering retrofitting a t case form a 60 or 62 series truck into mine. I think once you facotr the cost of a junk yard t case rebuild it and then change out the output shaft fromt he transmission I think you will be ahead of the game. again this is just my opinion so take it for what its worth. (adding an extra layer of nomex) of course this is form the guy who is planning a sbc to 4l80e to atlas II here in about two years.
Dave

 

[landtank]

Dropping the front drive shaft and locking the center diff will not imitate a part time system as the wheels are still attached to the axles and there drag will influence the feel of the truck.

The part time conversion I thought was just that and what you get is a part time drive line. I'd expect it to handle as a part time system.

 

[Beowulf]

>> sbc to 4l80e to atlas II <<

That would be a kewl mod for a 91-92; especially if you used a TPI version like the LT1.

-B-

 

[PHAEDRUS]

Rick,
I think the kit come with warn lockouts for the front axle so it really does make it a part time system.
-B-
as far as my pipe dreams go I am jsut waiting for a 98 + chevy truck to come into my shop and be totalled out. that way I could have all the wiring in its stock location to play with. my good freind back in SLC is a distributor for advance adapters and a hell of a good guy so I think I could get the case for not much more than cost. he specializes in swapping 700r4 trannies behind ford blocks in the early style broncos so weird fab is what he loves doing.
Dave

 

[Digger276]

Hey DougM, Thanks for the input, but I did say in the first para, that I was going to rebuild the tc, the kit is around 300. The reason that I suspect the tc, is two reasons: 1 When I put into drive there is a very strong hard clunk. 2:I got underneath and observed the tc as someone put it into drive then reverse, the forward drive shaft rotated at least an 1 inch before the clunk of it taking up the slack. I understand that these tc's will have some slack due to the amount of components. This one just sounds and appears to me to be excessive. Sooooooo, while doing the rebuild and having it apart I thought about the kit and there we are....I am trying to look through all of this and got a letter back from Ethan who wrote on Christo's site about it and he said it is still strong and doinf well. So still thinking but leaning on the conversion. CT