Installing 3 speed transfer gears into a 4 speed transfer case (2 Viewers)

[Cirbo]

After much research in the postings and FAQ, I was finally able to fit a set of lower (2.31 vs. 1.96) transfer gears into a newer style case. I will attempt to recount the process to regain a little karma after all the help that MUD has provided over the years.

 

[Cirbo]

I purchased a transmission and transfer from a MUD member close by. I noticed some wear on the input shaft of the transmission when I did an inspection, but the interior of the transmission looked fine. (note: transmission and transfer were still attached) When I brought the unit home and finally took it apart for a fresh set of seals and gaskets, I found that the input gear of the transfer case was badly worn. The seller did tell me that the cases had come out of a 40 that he parted out. This truck had a V8 installed, but was a non-runner.

As I was planning on attaching an H42 and stock transfer case to another V8, I wanted all parts to be in excellent shape.

It may not be easy to see, but the protruding teeth and slots should be the same physical dimension. When this gear was installed on the output of the transmission, there was quite a bit of free-play between the two.

 

[Cirbo]

When I broke the rest of the case down for inspection, I found an additional problem. The idler shaft was badly scored (closest to camera)

The scoring on both ends was 180 degrees out from each other.

 

[Cirbo]

While I was trying to decide what to do, I finished the disassembly of the '76 case and cleaned all parts. I bead-blasted the empty shell and assembled it with the worn parts and put it on the shelf.

 

[Cirbo]

I was in the process of tearing the LPB down for rebuild and found that the transmission was on it's last leg. When I opened the drain plug, a half cup of sludge came out with lots of rather large metal shavings.

After finding this, I decided to pull the transfer to attempt the gear change.

 

[Cirbo]

The best source for information was found here:

4 Speed Transmission mated with a 3 Speed Transfer

Good part numbers, but the pictures were missing!

 

[Cirbo]

I ordered new bearings to go with the seals and gaskets. The input shaft bearing was a little pricey, but I found an alternative (thanks Gabe!). The following picture shows a bearing part number this is a good bit cheaper. All you need to do is pry the dust shield off to make it exactly like the OEM unit.

In case anyone is interested in doing this job, I have two additional bearings that I would be willing to sell for what I paid ($20). I think the OEM units are double that price.

 

[Cirbo]

The bearing I should have skipped was number #37 in the first picture. It was a BiAtch to get out. It took a dremel and lots of separating discs to get it done.

Specter Off-Road Land Cruiser Parts - Page 070 Land Cruiser Transfercase, Shafts, Gears, Gaskets & Seals

 

[Cirbo]

Pulled the case out of the LPB and found why the transmission only had a half cup of oil. Some previous owner tried to stop a leak between cases with a liberal application of RTV.

Note: All the clean area on the lower part of the case is due to removal of RTV.

 

[Cirbo]

You all probably don't need another thread on how to tear a transfer case apart, but I'll add a few pictures for color.

 

[Cirbo]

I don't usuallly like to drive anything out with a brass mallet, but I thought I'd give it a try. I slipped the spanner I use for the side adjusters on differentials between the high speed and low speed gears on the output shaft and gave it a smack.

 

[Cirbo]

Low speed gear and output shaft with cluster re-installed.

Notice the course spline count on the output shaft.

 

[Cirbo]

The next thing I did was to remove the screw and lock plate on the idler shaft. I drove it towards the front of the truck to dislodge the small cover from the front side of the case. After the cover is off, drive the idler shaft back the other direction (toward the back of the truck).

 

[Cirbo]

The next thing to do was to remove the idler gear cluster and the associated shims/bearings.

Note: parts are laid out left to right as in back to front of the case (referring to how the transfer sits in the truck)

 

[3doghouse]

Subscribed.

 

[Cirbo]

After a quick cleaning, you see most of what is reused for the assembly. The intermediate (or idler) gear, low speed gear, high speed gear, two bronze transfer washers, spacer sleeve, and idler spacer. I did not reuse the roller bearings shown in the picture.

Note: the bronze washers from the 3 speed case need to be moved over to the 4 speed case. The smaller spacer (between the roller bearings) must be moved over to the 4 speed case as well.

 

[Cirbo]

The one key piece missing from the last picture was the "transition year" input gear. I posted on MUD and got a quick reply from Georg that he had new ones in stock. I purchased one, and while there, added his t-case and nose-cone savers to the order.

Thanks Georg!

 

[Cirbo]

At this point, I went back to the "well worn" 4 speed case for disassembly. I added this picture to show how I separated the low speed gear from the output shaft using a press.

 

[Cirbo]

Next in line, separating the high speed gear from the output shaft. Note how much thicker the four speed gears are than the 3 speed.

 

[Cirbo]

Reverse the process by pressing on a new bearing to sandwich the high speed gear in place on the output shaft. You can't see it in this picture, but I chose to use the fine splined output shaft from the 4 speed case. Both shafts measure exactly the same, but I suspect there was strength in numbers when shifting the 4wd sleeve over all those fine splines.