T86 Transmision grinding gears

So I dont know if this has been discussed or not before. I couldnt find the answear i was hopeing for in the search thread. But what I have going on is that my transmision will ocassionally not want to go into 2nd or 3rd. I have to come to a stop, shift into netrual and then i can pop it in to first, then shift normally. I know these old transmision need to a bit to warm up the oil, but it has done this even when i've been driving around for an hour. Im woundering if the PO put to heavy of an oil, or if is an internal issue that would requier a dissasembly. Buy the way its mounted behind a 225.
thanks for any input on this. i've been scraching my head bald over this.

 

sounds pretty messed up. if you can pull the floor pan out easy enough its just 6 bolts to pull off the shift tower and have a look inside. im betting its not pretty. though you might get lucky. it could be your shift forks/ slide rails then you wont have to pull the tranny just the top plate

 

Since you know nothing about the lube the PO has in it, I think you need to drain the trans and transfer and O.D. if you have one, and see what kind of metals you find in the gear oil. Drain and change all the lubes for general purpose. Your tranny may be on the verge of running dry. That will cause your problem.

 

i'll pop the cover off tonight and check, and drain the fluids while im at it. I hope its just an oil issue. maybe too heavey of a weight. but if it was that simple it wouldnt be a JEEP right.

 

My first guess is that the blocking rings (syncros) and/or hubs are wore out.

 

I'd change the lube before pulling the top if that doesn't fix it then check the transfer case input gear nut torque. If loose it will allow the main shaft to move back and forth causing the problem you have. If ok THEN I'd pull the top and inspect it. Reason for this order is these are the most common issues and pulling the top can disturb things changing the dynamic of the problem.
Posted via Mobile Device

 

unless it's filled with grease (or below 0*), I never had shift issues with my t86 (till I was racing a mustang, another story....) with 85w140 in it. sounds like no oil or worn bearings.

 

If it just clashed, I'd suspect the blocking rings. But since it won't go into gear at all, you have to think that something is misaligned.

Nick has a lot of experience with these transmissions - I would follow his advice and check the nut on the end of the main shaft. Changing the oil is too easy not to just do it - especially since you seem not to know what's in there now. You can go to Autozone or Walmart and buy a gallon of 85W90 gear oil for $12-15.

If the new oil and nut-tightening does not help, then I'd suspect something else that would cause misalignment in the main shaft and/or input shaft... sp. the bearings. The front main bearing typically wears most/first. Or possibly broken parts in the synchro hub.

 

From the OP, it apparently will still go into gear, just not the way you would expect it to. I am going to bet when the lube is drained, it will have more than a little brass in it, maybe even some brass chunkies.

 

So its been a week, or more since i asked the question and i finally was able to get around to actualy draining the transmission and transfer case. my honey do list was too long to get to it till today. Good news is that while I was draining the gear oil i did not notice any metal. bad news is the transmision only had about half of what its required. the transfer case had the rest. took it out for a test drive and i dont have the issue anymore. Yet. For now..

 

Please hurry with the results!! I too, a rookie, am having a similar problem with my '70. I shifts like a Porsche when it's "cold" but when it's up to op temp, find'em and grind'em!!

 

I had a similar problem after replacing a clutch and pressure plate in my 1970 cj5. To compound the problem my cj has a SBC V8 so the linkage adjustments don't exactly follow factory service manual guidelines.

After the change my jeep shifted sweet while cold and at low RPM around the farm. But go to town and after things got warm you couldn't get it into gear while stopped at a light. Solved problem by adjusting linkage to allow more stroke to depress pressure plate diaphram which in turn raised clutch disc further away from flywheel.

I know you didn't mention clutch replacement but I thought I would throw this out there for someone who might have intermittent shifting problems.

I could really bore you with other issues I had changing from a borg-beck pressure plate to a diaphram pressure plate but I don't think I could type that long.

 

i do know for a fact the PO did get the clutch changed before i bought it. He gave me a receipt for the labor and instal, i even checked with the shop before i bought it. good to go on that one. but for know i'm going to keep an eye on the oil level in the transmission and transfercase, untill i can aford the rebuil. it shifts fine now that i have put new oil in it, just leaks a little, sorry. "Its marking its sopt" thats what i meant.
but i do know, going by what i have read, that the t90 and t86 are natorius for "sharing" oil between them and the transfercsase. and a rebuild is ideal.
till then. its the old top off and drain method.

 

Just an FYI, rebuilding them won't fix the sharing oil issue. They are manufactured that way.....

 

my t-98 shares oil as well

 

thats good to know, then i'll not worrie about the rebuild for now and just keep an eye on the oil. thanks for the info guys.
im learnign as i go with this jeep

 

Brad, sounds like I will have to adjust my clutch linkage. Nickmil, if they were designed that way, when one tops off the tranny and the Tcase, will it still build up in the Tcase? If it does, then will the Tcase be running with too much oil? I mean if I check my tranny level and it is low, I add more oil and it builds up in the Tcase..sort of like a viscious cycle. Is this thought process wrong?

 

i got all confused myself when i got mine.
finally i just opened each up.
filled it until it dripped out the hole
then did the next one.
if it was too full i let it run out until it leveled off.

 

i havent had any problems with the transmission since i changed the fluids. i still am trying to figure out why they designed the transmission and transfercase to share oil. im stumped on that. it dosent seem like they were originally meant to do that. is there somthing that one can do to stop the process or to slow it down. i took a look at the fluid leval yesterday and the transfercase is allready to the point were it will drain from the fill plug, and the transmission oil is low now. mind you i have i parked on a leval surface and ive only put 30 miles on it since the fluid change.

 

So are we to keep filling the Tranny up as needed? What will happen when the Tcase fills up with oil? Perplexing. I assume the design is such that the Tcase should drain back into the Tranny at some point, right? Being a closed system, the level should even out, or am I thinking about this problem wrong?