'72 FJ40 t-case scary situation...need help. (1 Viewer)

[TeeTodd]

Hi folks,

New to 40's and would greatly appreciate guidance/ insight regarding this transfer case issue. I recently picked up a '72 FJ40 and am working through the issues. It has a '69 Chevy 350 sb conversion & what I believe is a TH350 auto trans that bolts right up to the Toyota (I think) t-case. I attached pictures of the problem. On the back side of the t-case a bolt was sheered off (I am likely to to have to try and drill out the stud) and it also looks like that bolt was holding on a small bracket (which also fell off) that was holding in a cylinder that runs through the center of the t-case. After a short drive, the cylinder come out a couple of inches (towards the rear end). I can press it back in (although the cap on front side of the t-case fell off when I pushed it in). It isn't leaking and there is no noticeable noise, but, obviously, this cannot be good. I tried to ID the cylinder and its function online, but haven't found anything aside from it being labeled a freeze plug (on Spector Off Road). No mention of online of the cylinder that is slipping out. I would be very grateful for someone to let me know what kind of trouble I am in here. Specifically, what is the function of the cylinder is and what I can do to fix it (if it requires more than drilling out the busted bolt and replacing w/ a new bolt).

Many thanks!

T

 

[Ian Macdonald]

You've got some gears running on that shaft. You DEFINITELY need to get that broken bolt out, and thread a new one in. The bolt holds a small flat keep that engages the shaft and keeps it in place.

 

[TeeTodd]

Many thanks Ian.

 

[Ian Macdonald]

Pleasure.

 

[Marn0]

Yes definitely do not let it fall out. It only needs to move enough to fall out of the case on the other side then the gear will drop on an angle and wear/punch through the bottom of the housing and then you will have to get the hole welded up.
Don't ask me how I know this.......

 

[TeeTodd]

Hahahaha!

I was able to push the shaft back in. Not going to drive it until I can tap that sheered bolt out. I think I've found the part I need: idler shaft lock plate (and bolt). Can anyone confirm I am correct in ID'ing the shaft as the idler shaft?

Thanks again!

T

 

[Travis 76]

Yes it is the idler shaft. There is a flat spot in it that the plate you ordered will fit into and the bolt will keep it in place.

 

[Travis 76]

It might be a good idea to take off the inspection cover and have a look inside the case to make sure none of the thrust washers have fallen off when that shaft moved. I'm not sure how likely that is maybe someone else has more experience with this.

 

[Alexh85]

Nah, i wouldn't worry about checking the thrust washers, if the shaft moved far enough for the thrust washer to fallout the whole transfer case would have blown apart. (The idler pin come loose in one of my mates trucks, and it punched a hole in the side of it, and locked up the rear wheels at 100km/h)

 

[Travis 76]

Ouch, that sucks.

 

[65swb45]

Isn’t anyone curious as to WHY the bolt broke, and what made the shaft move? That bolt is not under a load...unless something else is wrong.

I’ve rebuilt hundreds of transfer cases ( I’m rebuilding 3 in the shop right now) and when the inside of the idler gear and/or the bearing surface of the shaft are compromised, THAT is when the lateral load on the shaft starts that ends up snapping off the bolt. Torque over time also slowly wallows out the hole in the case that the shaft sits in, compromising the interference fit of the shaft.

In other words, you are only addressing the symptom, not the problem.

 

[TeeTodd]

Thank you! This is very helpful. I think I'll take a look inside and inspect. Thanks again!

 

[Dynosoar]

Be very careful. If the shaft was out more an a 13mm or so there is a good chance the thrust washer fell off and is now floating in the bottom of the case. You may have gotten lucky, but I would not chance it. Youe should pull off the PTO cover and see if it's still in place.

 

[TeeTodd]

The shaft was defiantly out more than 13mm, but, I think I may have been lucky because I was driving around for a bit and nothing grenaded. I am not going to take any chances though. After I figure out how to get that sheered bolt out, I am going to pull off that PTO cover. Can't thank you all enough.

 

[pjohnson]

Pull the cover and inspect first. If you find anything unusual inside, you are pulling the tcase out for a rebuild.

 

[TeeTodd]

Pull the cover and inspect first. If you find anything unusual inside, you are pulling the tcase out for a rebuild.

Good point. Thanks - T

 

[Splangy]

Nah, i wouldn't worry about checking the thrust washers, if the shaft moved far enough for the thrust washer to fallout the whole transfer case would have blown apart. (The idler pin come loose in one of my mates trucks, and it punched a hole in the side of it, and locked up the rear wheels at 100km/h)

The idler shaft pulled out a couple of inches which is plenty far to drop one of the thrust washers. It’s likely one of them isn’t in place anymore.

 

[TeeTodd]

Think I got lucky. Looks like everything is in place (aside from the broken idler plate bolt that I've made a mess of). Thanks again for your help, everyone.

 

[Splangy]

Those photos don’t show the thrust washers (although I may see one). Are they still in place?

 

[TeeTodd]

I couldn't get an angle to picture between the gears and the case. The thrust washers, if I've identifyed their locationcorrectly, are not lying in the bottom of the case between the gears in the sides of the case. However, it is very difficult to get a good view in there. Is there a better way to verify?