My Tcase is a dirty whore

[agent orange]

Well, last night i had another episode of the continuing saga of why my tcase is gay. After a long night of poker and drinking, me and my buddies decided to make a 2 a.m. trail run, and when we got out the the trailhead i did my usual routine of shifting to 4 low, pushing the 4wd button, and then airing down to give my slow ass tcase time to shift. This time, however, when i got back in the truck, no 4wd light on. I tried to rock it back and forth a little bit to get it to go, but i got nothing. I ended up just running the trail in 2wd (that was a thrill, i had to go hammer down on the uphill sections ), and just to be the little slut that it is, just as im finishing the trail the 4wd light comes on .

So heres the deal, everything is as it should be outside of the tcase, ive got MAC valves for my shifter solenoids, new vacuum lines, and i know that the valves work because it does go into 4wd, just when it pleases. I plan on taking the shifter mechanism off this weekend and fixing it, but id like to have an idea of what might be the problem before i get into it. Heres my questions:

1. Does this sound like and internal vacuum leak thats making it shift so slowly, or is it a linkage issue?

2. What parts do you guys think i should order in advance for this job? Can i reuse the gasket that holds the vacuum shift mechanism to the case?

Thanks in advance guys,
Matt

 

[pplkook]

Did it shift into 4wd after the foot to the floor routine?

That may answer the vacuum question...

other than that - got nuthin

-Jack

 

[agent orange]

No, it finally shifted into 4wd at the end of the trail, i was just idling along. There is sufficient vacuum to the solenoids, and all the hoses are fine from there on out. 4wd engagment seems to be independent of throttle position.

 

[Aseif007]

You should be able to disconnect the two lines that go from the soleniods (or what ever you have there now) to the diaphram and with the vacuum of your mouth shift in and out of 4WD. This is what I did when my soleniod went out after 15 years and 250,000 miles. Do you really need to press the H4 button when trying to go to L4? I didn't think you did, but I could be wrong on that one. Not sure if you have rebuilt the t-case but it is probably time since it is not shifting quickly. When you shift into 4L or 4H you have turned the front drive shaft to verify that the front shaft is free? If you are just going by the light that is not the difinitive indicator. The 4 wheel drive position sensor on the t-case could be bad/stuck. It sounds like either the diaphram is bad, or you have a bad line, or you need a rebuild, or worse you don't have enough vacuum to shift it (which is an even bigger problem) I have never been a fan of the manual shifting conversion. Waste of time if you ask me, and it didn;t solve the problem. Just get an FJ-60 t-case or take of the diaphram and use a FJ-60 style shifting linkage if it is that much of a bother, IMHO. Good luck.

 

[agent orange]

The case has about 10k on a rebuild. Havent had any issues with it until this mess. I have a vacuum pump, and i tried bypassing the solenoids and trying to shift it with measured vacuum and it was no faster ie it didnt shift. I may have some grit or something plugging up the air passages in the vacuum shift mechanism, may have gotten lodged in there during the time it was out during the rebuild or putting it back in. Oh, and i know you dont have to push the button when you shift to 4low, but it doesnt hurt anything to do it (just in case the other switch is bad). Does anyone know of what parts have to be replaced if i break this all down, the FSM sometimes is unclear on that.