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Filling up Manual Tranny and Tcase levels.

T

tkotitan

NAXJA Forum User
Location
Vermont, USA
'94 XJ 4.0L 2dr 5spd SE. NP242 (select-trac) Tcase.

Since the budget is super tight, I am going to a friend's place this weekend to use his garage since he is handier with cars then me and he has the tools and space. I need to do front brake pads and oil, so I might also ask his help in topping off transmission fluid levels.

What fluids do I need? From the searching I have done, the Tcase takes Dex/Merc II or III, same as the Automatic, but I have a stick-shift. I am not sure what the 5-speed needs, I found one place saying 10w-30 is fine for it, but that was for a YJ 5-speed.

When I put it in 4H, and without touching the gas but just clutch into it, I hear grinding in the chain and especially when I corner, so I just haven't been using the 4WD at all. I have heard horror stories in Vermont where there are a lot of XJs that the chain can stretch to the point of sawing-through the aluminium housing of the Tcase.

There is a bell-shape seal of the tranny (I think downstream, i.e, towards the rear axle) below the Tcase that is wet on the flat seal every time I get under there. It doesn't drip and leak on the ground, but clearly I am seeping tranny fluid. Is it likely both the Tcase and the 5spd, or just the Tcase by itself?

2+ years ago I had a young mechanic change my clutch and flywheel because they went. Right after changing it, I noticed the tranny would lug (like an engine running too low RPM but not the engine, definitely in the gearbox instead). I showed it to my mechanic and he thought it was just breaking in. But it never went away. An example of the difference is I have to shift into 5th gear at 55mph plus now, when before I could do 50 and not hear anything. I need to be going close to 60 to not hear any noise from the gearbox. The point is, I often am lugging the tranny a little bit and just have gotten used to it and can't help it.

Also, driving a 4.0L 5speed with stock 3.08 gears is a lot of fun. But it also puts a lot of work on the clutch, etc - I don't baby it and there are occasional clunks when I let out the clutch fully after shifting. Especially lately, I have been taking it up to high speeds and squealing the tires a bit for fun. SO, maybe it's just low on fluid from me beating on it.

Thoughts? I just need to know what fluid and tools are for this job, I haven't found anything specifically for XJ manual transmissions.
 
tkotitan said:
From the searching I have done, the Tcase takes Dex/Merc II or III,
Click to expand...
correct.
I found one place saying 10w-30 is fine for it, but that was for a YJ 5-speed.
Click to expand...
I believe Redline MT90 or Pennzoil Synchromesh are the two most popular choices as they don't attack the synchros.

There is a bell-shape seal of the tranny (I think downstream, i.e, towards the rear axle) below the Tcase that is wet on the flat seal every time I get under there. It doesn't drip and leak on the ground, but clearly I am seeping tranny fluid. Is it likely both the Tcase and the 5spd, or just the Tcase by itself?
Click to expand...
What you said was very unclear. There is a seal on the front of the transfer case as well as one on the rear of the transmission. Either one can leak.
The point is, I often am lugging the tranny a little bit and just have gotten used to it and can't help it.
Click to expand...
Lugging the engine is the result of being in too high of a gear and trying to accelerate. Not sure what you are describing.
I don't baby it and there are occasional clunks when I let out the clutch fully after shifting. Especially lately, I have been taking it up to high speeds and squealing the tires a bit for fun. SO, maybe it's just low on fluid from me beating on it.
Click to expand...
Transmissions don't consume or burn fluid like an engine would. If its low on fluid its leaking. And it shouldn't making noises such as you describe especially when driven correctly. Adjust your driving style and put in the correct fluid to start with.
 
Thanks for the reply Talyn.

I did some more research on the tranny, which I now know is the AX-15.

This important bit just dawned on me. When my mechanic changed the clucth 2 years ago, I bet he used AT fluid instead of the right manual gearbox fluid. That would explain the difference. I am having trouble getting ahold of him, but this is very likely, and could possibly explain the leak I am seeing.

My plan now is to top off the Tcase and totally change the manual fluid this weekend and see how things sound after that.
 
You need to separate your issues.

Start with the tranny fluid and see what that does for you.

I just picked up a YJ for my kid that has a fairly recently rebuilt ax15. It was kind of a bitch to shift. I swapped in Redline MT-90, it made a huge difference.

Change the fluids, clean the mess up and then track down your leaks.
 
Here's how the factory suggests you shift the transfer case and I've been doing this since these things were new and I worked at the dealership. Quoted from the owner's manual. The suggestions in ITALICS are mine.

"To engage, shift the transfer case lever from 2H to 4H while the vehicle is moving at any legal speed". I let off the gas, throw the lever, and then tap the gas and let off.

4L position: " To engage, slow the vehicle to 2-3 MPH , shift the transmission to Neutral, then shift the transfer lever to the right and pull firmly rearward to 4L".

To shift out of 4L, shift the transmission into neutral with the vehicle stopped, shift the transfer case lever to 2H, then to D if you have an automatic, or into first gear with a manual, and continue on.


Revised 01-31-2014
 
It's good to do all fluids so I plan to do that Saturday. I cannot afford Red Line, but since factory spec is 10w30, I am going to get a 5 quart jug of Mobil 1 for 25 bucks and use the leftovers for my engine oil change. I figure full synthetic will still shift better in the cold.

As far as I can tell, any good AT fluid at least of Dex/merc III is fine for the Tcase, and since it takes less than 2 quarts I plan to maybe get some better stuff.

Thanks for the info Cruiser, I lost my manual a few years back. I am not engaging the 4 until I change the fluid to try and save it.

As Talyn, pointed out lugging happens in the engine, not the gearbox. But there is not better way to describe it, if I am going up a hill in too high of a gear the engine will lug, but if I am going faster where the engine does not, I still get a lug effect with a noise coming from the gearbox, that increases if I give it more gas. It didn't do it before I changed the clutch and for all I know it always does it but is just hard to hear sounds over it in the Jeep. It is not a bad noise, it just sounds like gears whirring and churning. It could be engine lug that I am hearing in the exhaust and not the tranny but I doubt it since it started right after the clutch job.

I am trying to see if a local shop carries replacement drain plugs for the Tcase since those hex plug bolts look stupid.

Thanks for all the help guys, I will keep you posted.
 
Just got under there to double check my tools and the tranny is leaking just above the Tcase, so the lower joint where it is flat and straight across. It looks wet and shiny. Also The Tcase shaft going towards the rear looks damp, but not as bad. I am not sure if these two things are connected, but I don't see how - other than mutual wear.

I couldn't even locate the drain plug in the tranny for a while, it is so badly gunked up. I think I may bring it to the pressure wash and degrease the sucker tomorrow.
 
So, I didn't do the manual transmission fluid yet. I did brake pads today and then did the Tcase fluid.

The fluid is somewhere between 4-5 years old when I put the 242 in from a '96 XJ. It was dirty. And a few chunks of rusty metal were in the fluid, not insignificant. I engaged the Tcase and during any cornering I still hear a metal-popping and grinding sound, only when the 4H is engaged. It sounds like it could be coming from the front end.

Jeep needs tires and serious body work before I do any major work on it, but I may consider swapping to a 231 case down the road. Wondering if that is a project I can do in my buddy's garage. The guy at advance is an old Jeep hound and he was telling me the 231 has much better support and is a good Tcase. With the 242 I can engage it at highway speeds, but whopdee-doo when the thing breaks.
 
Lots of people posting they are successfully using 10W-30 in the AX-15. When I rebuilt mine I put GL4 in it, planning to swap it out after a few weeks with Redline. I thought I buggered the rebuld it shifted so badly. Put a mix of Redline MTL and MTL90 in and it shifted like a dream.

Oh, make sure you get the fill plug out before trying the drain plug. :}
 
Sorry to necro the thread but I'd figure I would update everyone. It took me forever to get to the fluids which I did this past week. I have a new problem which might warrant a separate thread but I'll mention it here first.

First off, I didn't do the manual fluid, it might be a bit low but odds are it didn't need it. I bought an oil change special at Advance (Mobil 1 advanced protection) and a regular Mobil 1 5 quart jug at Wal-Mart. I was going to use the extra oil in the AX-15 but the motor oil was so black I ended up doing two oil changes. Previous oil was first full synthetic quaker state from april. I let the oil drip out overnight on a slight uphill, put new oil in and had to futz with my drain plug and recycle the new oil and bucket was clean. The new oil that was in the motor cold for 20 minutes and came out dark brown with a layer of black floating on top. So I fixed my plug, put the dirty new stuff in (just under 5 quarts) and about 10 ounces of sea foam in the crank case and ran the motor hard. I have no tach just stupid dummy lights, but I eventually maxed out the motor where it misfired for a couple seconds and I backed off. I let it get good and hot, drained the oil it was all black and put the second bunch of Mobil 1 in and now it looks and feels better.

I ran into a friend of mine who is a smart mechanic and he said when you hear gears whirring in the manual tranny it is usually the throat bearing. When we did the new clutch and flywheel we reused the old throat bearing so that is why I hear whirring in 4th and especially 5th gear. So I am holding off on doing the fluid for now but I would like to do it so it shifts better in the cold.

The clacking/metal popping sound was from cornering in 4H due to a very bad U-joint on the front passenger wheel. I just changed it and the caps were more filled with mud and gunk than grease. So a note to Everyone - grinding sounds while cornering in 4wd is a u-joint. Bit of a hassle because I have non-ABS axles and they are 2/16" smaller than the ABS U-joints so I had to make a return and Advance had only one part choice in stock. Can't complain about the parts being cheap.

Now I have a new 4wd problem I will add below.
 
So, I did my research that the NP242 is designed to allow different rotation speeds between the front and rear axle - that is why you can engage the 4H while driving down the highway. Don't quote me on this, but I am guessing it makes more sense for a 5spd as well.

I (stupidly?) took this to mean you can have different tires for the front and rear and still be fine. Please correct me with a big stick if you know this to be wrong.

I have the same size tires front and rear, but very different grip patterns. They are all 235/75/15. The rears are studded wintermarks with medium tread, 40psi. The fronts are cheap wangler radials medium wear 35psi. Clearly the rear tires have better grip and this may cause the problem.

After we did the U-joint, my mechanic rode with me up a hill to test the 4H out. But this was on a dirt road, fresh snow and only in 1st and 2nd gear. The 4H was clearly working well in the snow so I dropped my mechanic off and drove away.

As soon as I hit dry pavement in 4H, going maybe 35mph, the front end started shaking like crazy. (I would say this describes the problem very accurately) It was as if both front wheels were driving on a rumble strip. My track bar bolt is a nigh-mismatch so we tack-welded it in place a while back. I make it back to my mechanic and realize the steering wheel is clunking so he gets under there and re-welds the track bar bolt solidly in place.

What I think happened here is my tires are a mismatch on dry pavement and the vibration broke the old weld on my track bar bolt. I know you're not supposed to run the 4H on dry pavement at all but I always have in the past on cold roads with no problems.

It's so awful I have only played with it a couple times and am now leaving it alone. It seems to happen when I get above 25mph in 4H, and then even though I put the lever down back into 2H it won't stop shaking until I bring the vehicle to a dead stop.

I did change the tcase fluid a couple months ago and I may have overfilled it a couple ounces (put the fill plug in when it was still dribbling out), but I doubt that would be it. A rectangular rusty flake about the size of a nickel came out when I drained the old fluid, so something could be broken in the tcase, but I doubt it since I ran it fine low speeds in the snow.

I am guessing when I get up to speed the difference between the front and rear wheels is too much and the tcase vibrates badly. So I need to find matching tires because even with studs in the rear the XJ is undriveable in snow without 4WD.
 
tkotitan said:
I (stupidly?) took this to mean you can have different tires for the front and rear and still be fine. Please correct me with a big stick if you know this to be wrong.

It was as if both front wheels were driving on a rumble strip. My track bar bolt is a nigh-mismatch so we tack-welded it in place a while back. I make it back to my mechanic and realize the steering wheel is clunking so he gets under there and re-welds the track bar bolt solidly in place.
QUOTE]
As long as all four tires have the same diameter, they shouldn't cause problems. Themis-match tread might have funny handling and tire sounds.

You BIG problem, the one causing the handling problems is the track bar. Instead of repairing the problem, your "mechanic" f...ed up the mount by welding the bolt...twice. That's not a repair, that's just a band aid to to get home with.
A loose track bar can cause all sorts of problems, including death wobble.
Now you need to find a real mechanic or welder have him rebuild the track bar mount. Then replace any loose steering or suspension parts and have it aligned
Click to expand...
 
Thanks for the input lazyxj.

The track bar is new (maybe a year or so old) the bolt never breaks but mine did and we found a slight replacement. It had death wobble beforehand but this new problem doesn't seem the same. Are you sure it is the track bar? It was welded before and didn't do this.

It snowed last night so I ran it some this morning. The 4H is fine up until 30mph then the vibration builds up to a bad level. It seems I can run around in 2H ok, but bearing left around 50mph was making some mild vibration noise. The track bar bolt and new u-jont are both on the passenger side.

I just have my doubt that it is the track-bar since the difference is so dramatic between 2 and 4 wheel. But I can see how it's like the u-joint - bad in 2, and god-awful in 4. If I can get a picture of the track bar I will.
 
hear gears whirring in the manual tranny it is usually the throat bearing
Click to expand...


Throat bearing? :} Guessing you meant throw-out bearing.

I'd consider replacing the throw-out bearing when doing the clutch, especially if its high mileage or done a lot of city traffic. I don't recall if the 94 had the external slave, but if it does the bearing is cheaper than the internal slave setup.

I learned a lesson about replacing the pilot bearing in the end of the crankshaft when you do the clutch. My MJ had the clutch replaced right before I bought it due to difficulty shifting. The actual problem was the tranny synchros, so I ended up rebuilding the tranny and left the clutch and pilot bearingalone figuring that was all new. Big mistake. They hadn't replaced the pilot bearing. 30k miles later it seized, chewed up the input shaft and ruined the main input bearing in the tranny. I had an automatic sitting in the shop so I ended up converting instead of trying to repair the tranny.

Throw-out bearing noise will usually change if you push the clutch in. Some gear whirring noise from inside the tranny is normal, especially if you're sitting there in neutral.
 
tkotitan said:
Thanks for the input lazyxj.

The track bar is new (maybe a year or so old) the bolt never breaks but mine did and we found a slight replacement. It had death wobble beforehand but this new problem doesn't seem the same. Are you sure it is the track bar? It was welded before and didn't do this.
Click to expand...

Track bar, bad tie rod ends, and bad alignment are the usual death wobble symptoms. True death wobble will scare the crap out of you as the front end starts bouncing around and won't stop until you're nearly stopped, versus bad shaking.

If you do have death wobble, crawl under the front, and have someone crank the steering wheel back and forth. Look for anything loose or moving, for example the bolt on the lower track bar mount, slop in the tie rod ends. Check toe-in the alignment (easy enough with a tape measure and some yardstick). Some will swear it's a bandaid, but a bad trackbar stabilizer can contribute to death wobble.

Welding the track bar bolt isn't necessarily bad. Usually if the hole is egged out, you just weld a washer over the hole.

Cupped tires and bad u-joints can cause bad shaking and trigger death wobble if the rest of the suspension has play. You sure the u-joints on the front drive shaft are good? I think a 94 Dana 30 still has a vacuum diconnect, so your front drive shaft doesn't spin when you're in 2wd.
 
I definitely had true death wobble before the new track bar - would hit a bump and the whole rig would violently shake and I was lucky to regain control. This is not that, this is just front end feels like driving over rumble strips when in 4H above 30mph. Even when on a straight road and no bumps.

Not sure what you mean by cupped tires - they are a bit wide for the rims and actually the front wheels are more worn in the middle than the outside of the tread because they used to be the rears.

I haven't checked the front driveshaft U-joint and probably should. Trouble is funds are still low. I only drive once a week or so to town doing non-insterstate driving so it may have to get me through for a bit.
 
if you have a nv242 you don't have 4hi. You will have 2wd, 4 wheel part time, 4 wheel full time, neutral and 4lo.

If you have 4hi N and 4lo, you have a nv231.
 
Digger87xj said:
if you have a nv242 you don't have 4hi. You will have 2wd, 4 wheel part time, 4 wheel full time, neutral and 4lo.

If you have 4hi N and 4lo, you have a nv231.
Click to expand...

Good. Call.

Bonehead move of the week goes to me!!!!!!!!

It's a 231. Always was. Just got under there and checked. It needs matching tires all around. Wonder if I can get by in 2wd like this.

Does this mean I am not supposed to even engage the 4H while driving?
 
tkotitan said:
Good. Call.

Bonehead move of the week goes to me!!!!!!!!

It's a 231. Always was. Just got under there and checked. It needs matching tires all around. Wonder if I can get by in 2wd like this.

Does this mean I am not supposed to even engage the 4H while driving?
Click to expand...

Not while driving on dry pavement.

The 5 speed only came with the 231 part time case. If you have a 242 someone swapped it in, but as stated before you wouldn't have 4hi you'd have 4 full and 4 part.

You can engage it while driving on dirt or other loose surfaces.

And to the earlier comment 94s are not disco Dana 30s
 
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