Transfercase preload- Bearing retainer ACTUAL torque is it 25ft. lbs? (1 Viewer)

[SWCruiser]

Ive just about got my transfercase buttoned up but now stuck on the preload. Ive read coolermans rebuild and watch George's rebuild also. Both very helpful- Im now trying to measure the preload with a fishscale and not sure about what the actual reading. Coolerman says 12-13 lbs on the scale. FSM measures in inch/lbs. 6.1-10.4 inch-lbs.

I followed the method in the FSM and got .34 lbs. Coolerman states 12-13 lbs. seams quite high to me. Anyone help out with this?

Also the output bearing retainer torque in the Toyota trans manual says 25 ft. lbs. Coolermans says 12-14 ft. lbs. The FSM actually doesnt provide it. 25 seemed on the high side as I was torqueing down. One of the bolts stretched. Anyone confirm these numbers.

This is for a 78 t case.

thanks

 

[MoCoNative]

I'm no expert on rebuilding cases, but I went through the same thing on my case. In fact, the idler shaft gears had too much end play on mine. I added a shim to it to get it in spec. When putting the output shaft back together, I started with the shims that were in it under the rear cover, and had minimal preload. I then began adding shims. I think I may have bought the pack of shims from SOR or Toyota. Either way, I think I ended up with most of them stacked under the rear cover before I got anywhere close to the preload as you are describing. Some things to remember. The gasket can have some effect on this. The original gasket was pretty thin. I reused the one I had taken off while setting preload, then did the RTV skim coat to the new one, which was pretty thin and buttoned it up. You also need to get the rear nut on the drum torqued down good each time. I left the seals out while I set everything up, then put them in, the ebrake backing plate, etc when I was all done.

My theory, supported by some others is that the cases stretch over time, as in the internal width increases. I'm sure I encountered that, as I noted above my idler shaft and the gears on it were too loose, as in they had too much space between the sides of the case, even with new thrust washers. This stretch would carry over to the output portion of the case, as you are compressing the bearings with the rear cover. If that has grown, then the cover becomes too far from the rear bearing race and does not compress it for the preload.

Try some more shims if you can, otherwise it will probably be okay if you have no wobble in the shaft after assembly. There are probably lots of them running around out of spec I suspect. I guess I did alright on mine, did all new bearings and such when I converted my 3 speed to a 4 speed re-using the 3 speed case. So far no problems, that was a few years ago, and many thousands of miles, haven't even had my leak return. Prior to rebuild I kept getting a leak and my drum was loose.

 

[SWCruiser]

Thanks Moco. I was surprised at how easily it spun. Ill order the shim pack and give it another go. Do you happen to know what torque you used for the output shaft retaining collar ( speedo gear housing? Ive done tooo much research and each manual says something different. I read 25ft. lbs on one thread and coolermans said 12-14. The Toyota transmission repair manual also says 25ft. lbs. Seems like to much to me.

 

[MoCoNative]

Those are pretty small bolts and I have snapped some of those in other spots on other trucks in my fleet. If you go to Coolermans website he has the Body and Chassis Manual from 1971. That is what I have in print and used on mine. Page 2-27 has the procedure and torque specs you need. It notes 7-11 ft/lb. It notes for the 3 speed transfer. I looked some, didn't see another procedure for the 4 speed in the following pages, may have missed it, although the tranny is covered in the following pages. I don't think there is a difference in them. I can't see that changing on the 78 4 speed either. What determines the torque on those couple of bolts is the actual bolt used. Correct me if I'm wrong, but I think they are all marked with a 4 or 6 on the head. There are also a couple of longer ones as I recall. The back of the manuals have a general torque table for the head marking and thread pitch of the bolts.

If you work with SAE bolts at all, we have grade 2, 5, 8 and each one has a different strength. Toyota bolts come in more grades, as do all metric hardware. They were pretty picky about what grade they used where. Bottom line, 25 ft/lbs will snap the 6mm "4" marked bolts sometimes. The most important thing on this piece is that it sets down square and true and that each bolt is good and tight. An additional comment, unless you have a really nice torque wrench, and you have kept up on its periodic manufacturer recommended calibration, than by all means use it. Buuut, I have found at lower torque settings that the wrench does not always work properly, or the click is so slight, that you go right past it. You are pulling on a pretty long arm with a torque wrench, even a 3/8 wrench. Bottom line, the torque they want, is all you can put on them with your normal length 3/8 ratchet, or even for good measure a 10-12" 3/8 breaker bar. Unless you are the Hulk, you will have them plenty tight. Just go around them a few times, do a cross pattern, whatever, but you should be fine. Anything under 25 or so I just use my judgment with the ratchet.

I would go all of the 120 some pounds asked for by the transfer drum nut though. I had to build a pretty hefty bar to hold that one, bonus, after you build that bar, it can be used on the diffs too. I mimicked the tool shown in the manuals by drilling a piece of angle iron with two holes to match driveshaft pattern. You have to grind out a little in between to get the socket on the nut in the center. Enlarge one hole, or slot it and it will work on other Toyota applications, as the spread of the driveshaft holes varies by year and vehicle sometimes.

 

[SWCruiser]

Thanks again. Yea the bolts I had were numbered with a 6. I’ll go look up the general torque specs.
I made up a similar tool just as how you have described. I only snugged the nose cone to 100 ft lbs though.