QT Swap: What's the record for time?

[Bob Barry]

'cause I've got to do mine. The truck was running so well tonight, with the Holley carb giving excellent low-speed response. I figured I'd gun it from a stop and see how it would work at WOT (I never need more than 1/8-throttle to get around in most driving). So I nail it, and get a horrible RAT-TAT-TAT-TAT from under the passenger floorboard... so now I know first-hand what a QT chain sounds like when it's jumping teeth. Or a center differential with shot drive splines... :(

Not such a big problem, as I've got a good spare QT to put in its place. Thing is, I want to do it right-quick, so I'm looking for advice on how to make it as speedy a swap as possible. Here's the plan:

* Drain QT fluid and Unhook driveshafts
* Unhook linkage, cable and hoses, and remove reduction unit
* Support tranny at pan and unbolt tranny-mount
* Pull tranny access plate under carpet and loosen upper bolts from the case to the tranny
* Remove lower bolts to tranny and remove transfer case.

Transfer good e-drive diaphram and original speedo drive gear (this replacement case came from a 3.08 geared truck, but mine's running 3.54's) to the new case, add breather hoses to vents, and installation is reverse of removal.

Well, that's the plan, anyway. Are there any shortcuts or steps I'm forgetting here?

I do have a few specific questions, though:

1. Should I keep the original speedo gear for the 3.08 axles, since I'm running 33" tires with 3.54 gears and the speedo is reading about 12-15% low (I'm doing 57mph but the speedo reads 50mph). Would that make for a better ballpark speedo reading? Or would it screw it up even more?

2. The E-drive fork in the replacement transfer case slides a collar from a ring with many teeth to a ring with a few teeth; the thing is, I can't manually get the collar to slide because the two gears turn together. Should they normally be able to rotate independently, or is it just that the clutches in the center diff are particularly tight?

3. The chain shows about a 1/2" of slack; from what I've been able to read, that's within tolerances, right?

[Red78j10]

The fastest way to do it. Is to take off the back drive shaft, and split the case. you don't have to remove it from the tranny. Just split the case and replace what you need. If you need to replace the diaphram, or the chain, just take them from the spare case. when I replaced my chain I took off the t-case, and someone from this forum told me I wasted my time, and that I should have just split the case and do allthe work from under the truck. you would be suprise how much room there is. good luck .

[Red78j10]

1/2 of slack is pretty normal, and exceptable, I had about 2 inches in mine when I replaced it, and it never sliped, My problem was the cone gears in the diff.

[River Beast]

Leave the adapter plate on the tranny.... that way you only have 4 bolts to the QT to contend with and the tranny will still be supported and no need for extra support under the pan....

Are you rpelacing any seals on the one going in?

I suggest that you at least change the 2 back-to-back seals where the tranny outputshaft goes threw the QT.... BE CAREFUL... the have to be facing the direction that you pull them out. These two seals can be important if your tranny seals every go.... keep the QT fluid in and the ATF out....

I did a QT swap a while back with Porkchop's help... well I snapped my adapter plate in half so same amount of work ;)....took about an hour.... didn't even drain it!

[Hump]

Never done a QT swap, but I pulled a NP229 at a salvage yard in about an hour and a half. That didn't include reinstalling it on my GW, but I never got to that. :mad: (long story)

So garage or driveway conditions would make it much better than laying in neck high weeds.

The biggest problem that I encountered were the bolts on top of the t-case. I couldn't get a ratchet and socket up there with my hands, so I ended up struggling with an open ended wrench until she came out. So a word to the wise, take the top bolts out first. I didn't, and found out quickly how heavy an NP229 really is. You know how you think you will "just know" when the bolt is almost out, and then position the jack stand under it. Luckily there was barely any space between my chest and t-case when it came loose, or i'm sure I would have broken something. :(

[reddog]

If my brain is working this morning then the speedo gear from the 3.08 axle setup should be just about right for you 3.54s

3.54 / 3.08 = 1.15
1.15 * 50 = 57.5

Kerry

[Bob Barry]

<BLOCKQUOTE>quote:</font><HR>Originally posted by reddog:
If my brain is working this morning then the speedo gear from the 3.08 axle setup should be just about right for you 3.54s

3.54 / 3.08 = 1.15
1.15 * 50 = 57.5
<HR></BLOCKQUOTE>

Thanks, Kerry; that's one less thing I'll have to swap.

I was figuring I mitaswell the seals, if I can get a kit locally. Since I only ran this replacement case getting it up my driveway, I don't know how good it is; I do know it shows signs of having work done to it at some point in its life, and the chain is relatively tight, so I'm thinking of doing the seals, checking the internals and bolting it in. A local tranny supply place says they have the seal kit on the shelf for about $25, so I'll at least pop it open for a look-see.

Now, are all those needle-bearings caged, or am I going to be hunting them down as they ricochet into part of my garage unknown? I don't want any surprises when I pop this baby open.

[River Beast]

Bob,

You can check the chain out before you swap it out...prop it up somehow to orient it as if it we installed and check it thru the the normal procedures...

As for the bearings in the QT... All of them are caged... no bearings need to come out to do the seals. You can buy a whole kit if you want or buy just the press seals individually....

The QT by name sometimes scares people by name.... once you open it up... they are pretty straigh forward. I know you won't have a problem.

Just be sure to remember the orientation of the E-drive fork... it's offset to one side.. if you get inot it that far. OH... and it's got little nylon end caps around the coupling ring... DON'T LOSE THEM...

[jeepbob]

If you are good you can change a q/trac out in about 20 mins. If you dont have a tranny jsck (or floor jack) pull off the low range unit and installation will be much easier.

[River Beast]

Jeepbob....lo range has to come off requardless.... the snap ring.....right under the lo range....

Am I just too tired or am I right....

oops.... never mind..... just tired...... ;)

[ November 30, 2001: Message edited by: River Beast ]

[jeepbob]

You are just tired as you can put it in with the low range on but it can be a pain with the fuel tank right there if you don't have a jack. Being a small guy, I find it difficult to pick up and install the unit with the low range on it. If I take the low range off I can do it but I prefer to use the jack.

[River Beast]

Yeah....the tank can be in the way on them... except my factory tank doesn't exist anymore (in the rear) and I can sqwat under my rig and remove it!!!! PC was there..... it was a cake-walk... :D

some advantage to riding in the clouds I guess... ;)

[Bob Barry]

Nothing's ever easy, is it? The front yoke nut came off easy enough; the rear isn't coming off for ANYTHING, not even with a 3' cheater bar, and noplace open tonight has a 1 1/8" impact socket. :(

Besides that, the center diff starts giving way at about 18 ft/lbs... :( :(

Would it make a difference that the transfer case is dry? Or do the cone clutches have to have the friction modifier to give an accurate torque measure?

Anyway, it looks like I'm going to be piecing the best parts from both transfer cases together; maybe even just swapping the chain from this extra case into the new one.

Anyone want to come over tonight and stand on the case while I jump up and down on the cheater bar? smile.gif
[edit]

OK, well, I laid the cheater bar on a step, raised up the end of the case with the yokes, got the socket wrench clicked onto the nut, laid a board on top of the case, and then jumped up and down on it until the nut broke free. Not pretty, but it worked... smile.gif

I got the case apart w/o breaking anything (though I didn't know the planetary had to come off to remove the back half of the case, and those pesky dowel pins didn't want to let go), and it looks like the chain is stretched at least an inch or so. :( I may as well get a good chain and slap it in whichever case turns out to be in the best shape.

Luckily, the splines on the center differential look perfect; that's one less unobtainable part I'll have to hunt down...

[ November 30, 2001: Message edited by: Bob Barry ]

[River Beast]

The planetary snap ring was the one I was thinking about... right under the lo range unit ;).

It does make a difference when the brakecones are lubed properly.

If you want my advice....do as you said and take the best of both worlds.

Take apart the center diffs and inspect them thoroghly. I HIGHLY recommend you check out the page on my original site that shows what to look for inside the center diff....once they stop cutting off my site from too much bandwidth.... :mad:

I also can tell you how to get back some of the torque needed in the center diff...if you want...since you have two cases.... lemme know... ;)

[Bob Barry]

<BLOCKQUOTE>quote:</font><HR>Originally posted by River Beast:
I also can tell you how to get back some of the torque needed in the center diff...if you want...since you have two cases.... lemme know... ;)<HR></BLOCKQUOTE>

Nah, I don't want to know how to restore my case to good working order... ;)

E-mail the instructions to me at rbarry@providence.edu, if you don't post them here.

Actually, I suspect that the case in there now has a pretty good center differential, since I can feel some binding on real tight turns in normal non-E-drive mode.

I'm hoping the tranny shop parts counter is open tomorrow; it would be sweet if they had a chain in-stock.

[River Beast]

haha..... :D

I just didn't want to spend all night typing on the forum.... I'll send you the instructions via email.... Zack helped me out a few years back and it works....