Filling up Manual Tranny and Tcase levels.

[lawsoncl]

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?

You should only use the 4H on slippery roads or offroad. The diameters do need to be pretty close. Too far off and you'll get bucking and put lots of stress on the drivetrain.

You're fine in 2wd. Just save the 4wd to get yourself out of the ditch. :}

 

[tkotitan]

I swapped it with a part from a 96 a few years back (supposedly there was a compatibility issue which required disassembling and merging the two, but that mechanic may have been a rip-off).

I have a cd-carrier blocking my driver's visor and it says command-trac. I checked the tag on the tcase and it is 231.

So, driving on snow, I can engage on the highway. I have to have a matched set of tires because there is no viscous coupler in the 231 right?

I either have to find a matched pair of an OOP winter tire to complete my set, or I have to find another single Goodyear Wrangler radial to match my full size spare on the roof. The latter is easier but I would prefer the former. Even still, treadwear difference can be an issue if I am not mistaken - the tolerance ranges is what, 3/32"?

 

[lawsoncl]

the tolerance ranges is what, 3/32"?

Sounds reasonably close. 3/32" on for 29" tire is 0.6% difference.

Difference between the rear diff and front diff gearing is a few tenths of a percent anyway.

 

[Digger87xj]

Viscous coupler or not you always want tires with matching diameters on any AWD or 4WD. In fact, mismatched tires will destroy a VC pretty quickly.

 

[Talyn]

Who said anything about having a VC?

 

[tkotitan]

So, am I in any trouble for 2WD? My manual tranny is making a bit more noise in 2H in 4th and 5th gear going up a long shallow hill around 50mph (stupid instrument panel with no tach). It only happens when I gas and the gears are engaged. Part of me thinks it's the cold, but I really need to top off fluid in the thing at least. Vibrating bit more noisly is all and I hope the old throw-out bearing hangs in there.

But just wondering, will mismatched tires on a NP231 rig cause any other problems while only in 2WD mode?

 

[IslanderOffRoad]

No not in 2wd

 

[xcm]

This thread is all over the place.... but...
Motor oil powdered my synchros, **** the factory and anyone else who lists it as the spec fluid, they owe me an ax15 rebuild.

 

[Digger87xj]

Who said anything about having a VC?

I swapped it with a part from a 96 a few years back (supposedly there was a compatibility issue which required disassembling and merging the two, but that mechanic may have been a rip-off).

I have a cd-carrier blocking my driver's visor and it says command-trac. I checked the tag on the tcase and it is 231.

So, driving on snow, I can engage on the highway. I have to have a matched set of tires because there is no viscous coupler in the 231 right?

I either have to find a matched pair of an OOP winter tire to complete my set, or I have to find another single Goodyear Wrangler radial to match my full size spare on the roof. The latter is easier but I would prefer the former. Even still, treadwear difference can be an issue if I am not mistaken - the tolerance ranges is what, 3/32"?

The OP did

 

[87manche]

sweet jeebus.

You have a 5 speed with a 231.
Don't use it on dry pavement.
Don't use it on wet pavement
Use it when there's snow covering the road or off the road on a loose surface.
It's not going to care much about different tread patterns, but tire diameters should be reasonably close.

Don't use 10w30, use MT90
Don't bother with the fill plug, just pour four quarts in from the shifter. Remove boot, push the silver cup down and turn it, pull out shifter. Pour in four quarts of MT90 or syncromesh, install shifter in reverse. Trust me. Your AX-15 will appreciate the extra .5 quart oil for the output bearing.

FWIW I'm on my third 4.0/AX-15 jeep in 8 years. Haven't killed one yet.

 

[Talyn]

The OP did

The op is confused as hell and the 231 doesn't have a VC. Neither does the 242. And anyone that would swap in a 249 from a ZJ (which has a VC) is a moron.

You have a 5 speed with a 231.
Don't use it on dry pavement.
Don't use it on wet pavement

This. Learn how to use the transfer case correctly. Never put it in 4x4 if you aren't on a lose surface (show, dirt, mud, etc.). The wheels need to slip so they don't bind the case. If you do bind it up you might have a hard time getting it back into 2wd.

 

[tkotitan]

All my confusion stems from the fact that for some reason I thought I had selec-trac when in fact I have command-trac.

According to the wikipedia page, it implies that the NP242 has a viscous coupler, but does not state it. Just says it is similar to the 231, but not in what way. If anyone here has a wikipedia account feel free to clarify over there. I was confused because it says the older selec-trac systems did have a VC.

http://en.wikipedia.org/wiki/Jeep_four-wheel-drive_systems#Selec-Trac_2

I don't mean to sound stupid, but I am being told the tires need to match all the way around, BUT I can only drive the NP231 where everything is slipping (dirt, mud, snow road, etc). On their face these two ideas seem to be mutually exclusive. Anyone care to explain in more detail? In the past with matching wheels I have engaged the Tcase at interstate speeds (60-70) and had no problems. But not as a daily driver or anything. I live in VT so most of my rough conditions are dirt, mud, or snow-covered roads.

As for my AX-15

I don't have the setup for a proper drain and fill right now with outdoor weather. I did just top off the AX15 with about 1/2 quart of 10w30 through the side fill port. It feels a bit better but is hard to say since it is much warmer out today. It might be the bearing or even gears at this point.

When I get the money and setup I will drain and redo all the fluid. Now to restart this debate - it seems I need to worry about sulfur-based oils ruining the yellow metals. I have read that motor oil does not have these compounds, whether conventional or syntehtic. My preference is still full synthetic 10w30 motor oil. I realize this will have additives designed for motors and not transmissions, but that doesn't worry me.

Thanks for all the input guys, I really do appreciate it especially since it helped me figured out what I was confused about.

 

[Digger87xj]

When the 231 is in 4hi (or a 242 in part time) both front and rear driveshafts rotate at the same speed; this means that when the front wheels are turned, the driveline will bind because the outside wheel on the rear axle is turning faster than the other 3. This is bad for all the components that make up the driveline.

In the case of the 242 in full time mode, the front and rear driveshafts are connected by a center diff in the transfercase and allows for different drivshaft speeds while turning reducing bind.

Having mis-matched tires has the same effect on the driveline.

 

[87manche]

My preference is still full synthetic 10w30 motor oil. I realize this will have additives designed for motors and not transmissions, but that doesn't worry me.

a 242 has a diff in it, a 249 has a VC. It doesn't matter regardless since you've got a 231, so stop bringing it up.

Go ahead and fill your AX-15 with 10w30, we'll wait for the "I need an ax-15" thread.

Fill it with MT90 or syncromesh or suffer the consequences.

run a 231 on pavement and as soon as you attempt to turn it will bind, and then stretch or break the chain. Either will result in a case rebuild. The latter potentially will destroy the case.

here's the instrutions straight from Jeep
http://www.jeep.com/en/4x4/faqs/

since you don't seem to like taking advice from people with experience.

 

[xcm]

As for my AX-15

I don't have the setup for a proper drain and fill right now with outdoor weather. I did just top off the AX15 with about 1/2 quart of 10w30 through the side fill port. It feels a bit better but is hard to say since it is much warmer out today. It might be the bearing or even gears at this point.

When I get the money and setup I will drain and redo all the fluid. Now to restart this debate - it seems I need to worry about sulfur-based oils ruining the yellow metals. I have read that motor oil does not have these compounds, whether conventional or syntehtic. My preference is still full synthetic 10w30 motor oil. I realize this will have additives designed for motors and not transmissions, but that doesn't worry me.

Thanks for all the input guys, I really do appreciate it especially since it helped me figured out what I was confused about.

Do as you like, but when your syncros exit via the drain plug, come back and update this thread. http://www.naxja.org/forum/showthread.php?t=1114345

 

[tkotitan]

When the 231 is in 4hi (or a 242 in part time) both front and rear driveshafts rotate at the same speed; this means that when the front wheels are turned, the driveline will bind because the outside wheel on the rear axle is turning faster than the other 3. This is bad for all the components that make up the driveline.

In the case of the 242 in full time mode, the front and rear driveshafts are connected by a center diff in the transfercase and allows for different drivshaft speeds while turning reducing bind.

Having mis-matched tires has the same effect on the driveline.

This explanation makes no sense to me. I do understand that my current setup with mismatched tires will put a strain on the transfer case if both driveshafts are locked up. The vibration is happening while driving in a straight line. That I do get.

As far as turning is concerned - why does my front axle have a pumpkin? Are you saying the front differential is locked and the 4WD does not allow the front passenger side wheel to rotate at a different speed than the drivers side wheel? I could see there being a limit on this for tight cornering at the extreme range, but I am shocked to hear that my front differential does nothing.

 

[tkotitan]

a 242 has a diff in it, a 249 has a VC. It doesn't matter regardless since you've got a 231, so stop bringing it up.

Go ahead and fill your AX-15 with 10w30, we'll wait for the "I need an ax-15" thread.

Fill it with MT90 or syncromesh or suffer the consequences.

run a 231 on pavement and as soon as you attempt to turn it will bind, and then stretch or break the chain. Either will result in a case rebuild. The latter potentially will destroy the case.

here's the instrutions straight from Jeep
http://www.jeep.com/en/4x4/faqs/

since you don't seem to like taking advice from people with experience.

Thank you for the link. From their site: "Part-time 4WD systems effectively lock the front and rear driveshafts together, forming a single driving unit that does not allow for differential action between the front and rear driveshafts."

This is a somewhat confusing statement (in the current context of this thread). I understand there not being a differential between the front and rear driveshaft. But I clearly have a differential for left and right-side wheels, via the differential pumpkin joining the axle shafts.

You're making it sound like all 4 wheels are always turning the same speed and the only way the 4WD can work without damaging itself is if all of these same-speed turning wheels are just slipping like crazy all over the place - which would mean they are not moving at the same speed so I don't see how this avoids damaging the Tcase. No one has answered this question yet.

As for the AX-15, I may be boned anyway because I don't know what my mechanic put in when he did the clutch 2 years ago. if it was GL5 I am screwed if it's AT fluid I may be ok until I have the funds to get better stuff. It is not logical to assume that the only reason a transmission fails is because of fluid choice, especially when we are all running rigs that are at best 11 years old, mine is 20. But yes, if my synchros come out the drain I will tell you all.

If I had a problem taking advice from people with experience, I wouldn't be here. However, I never just do what I am told from people who don't want to answer my sincere questions. That's how religions (among other so-called authorities) have ruined the planet. "Shut up and do what I say" always deserves the middle finger. And no one made you post an answer to my questions.

 

[Digger87xj]

the front turning wheels, because they are turned are going a different speed than the rear wheels, because they are not turned. This causes all 4 wheels to be turning a different speed during the turn. The differential action only works in the diff that it is installed in and does not equalize driveshaft speed. Only a center diff or viscous clutch can do that.
The unequalization of driveshaft speed is what causes the bind up.

 

[tkotitan]

the front turning wheels, because they are turned are going a different speed than the rear wheels, because they are not turned. This causes all 4 wheels to be turning a different speed during the turn. The differential action only works in the diff that it is installed in and does not equalize driveshaft speed. Only a center diff or viscous clutch can do that.
The unequalization of driveshaft speed is what causes the bind up.

Ok THAT's good answer Digger, thanks. Sorry if I am being a dick.

 

[tkotitan]

I remember now like 5 years ago I has mismatched treads (matched pairs fronts and rears) but no problems because they are all close tread depth. So I agree now that tread pattern doesn't matter so much as does wheel size. Just had the depth checked.

Rear pair is both 10mm in good shape. Front tires are worn on the inside 7mm on the outside, 2mm on the inside. (the other is 6/1). So I need a new matched pair between 8 and 12, but I prefer between 8 and 10 since the rears are good studs.

The tranny mount may be cracked giving me vibration at higher speeds. The axle u-joints are ok.