So, they went back to the 3-lock after Renix sometime?

 

I guess so, that's the way our's is.....light throttle in D (3rd) it'll definitely lock-up. Little heavier throttle, it won't lock-up 'till OD.

 

Wondering; if you put the shifter in 3 would it let the tc lock? Just wondering

 

It did work that way on the 87s so I imagine it would have to have been designed with 3rd gear torque lock to begin with. Try yours and let us know.

 

Not so much.

The torque converter is a three-element turbine between the engine and transmission that forms a fluid coupling element. Later models (ca. 1980-up) of automatic transmission became equipped with a "lockup" torque converter - the torque converter remained a three-element hydrostatic turbine, but a mechanical clutch was added between the drive element and the driven element.

Being a hydrostatic turbine, the torque converter allows a certain amount of "slip" between drive and driven elements, which means you lose some speed going through the thing (however, you do also get a slight increase in torque through the thing.)

A mechanical friction clutch is a 1:1 selectable mechanical coupling between two shafts - and that's what makes a "lockup" torque converter lock up. The transmission control system (hydraulic or electronic) can tell when the vehicle is in a steady-state cruise, and it will engage the internal clutch in the torque converter - which eliminates the "slip" that is otherwise inherent in the system, and allows you to cruise at a slightly lower crankshaft speed (which can increase fuel economy - if the crankshaft speed still remains in the "ideal" range for that engine. For the 6-242, that's about 2400-3200rpm, generally speaking. Below that, you're at risk of "lugging" the engine and don't have all available torque. Above that, you're just running it too hard to cruise.)

For the AW4, converter lockup is available (from the controller) in 2d, 3d, and 4th gear. You can also wire in an override switch so it's manually available in any gear.

Another advantage to the torque converter clutch is the reduction of fluid friction in the torque converter itself, which reduces operating temperature. This is a good thing for the clutches inside the transmission (there are about thirty wet-bath clutch plates, counting friction and steels, as I recall) since it helps keep them from getting glazed - which leads to slip and chatter.

 

A 7 speed then....just kidding. LOL

 

^ exactly what i wanted to read about actually, i kinda knew how the tc worked before but didnt quite understand the lockup bit untill now , thanks!

 

Actually, you're not far off.

You don't have "seven ranges" in the sense that the 5-45RFE has five ranges (it's a four-speed slushbox that has two second gear ranges - one for upshifts, one for downshifts,) but you're close enough for government work.

Eliminating the "slip" inherent in the fluid coupling effectively changes the drive gear ratio - if only slightly - which is why the crankshaft speeds dips just a bit when the TCC locks up.

So, it's a four-speed gearbox, but 2/3/4 each have a "half-range" due to the TCC, so it could be said to have 1/2/2.5/3/3.5/4/4.5, if you really want to be pedantic (it's not thoroughly technically correct, but it works for an explanation.)

 

It should. TCC lockup is spec'd to be available in 2d, 3d, and 4th - regardless of range lever position (if the gear range is available, TCC lockup should be available for that range as well.)

 

What's your question? I don't quite understand.

However, I do believe that the O/D ratio changed slightly sometime early in the HO years - but, the AW4 was in constant use in the XJ with the 6-242, 1987-2001. Also the MJ w/6-242 1987-1992, and the ZJ with the 6-242 in 1993-early 1994 (after which, it was replaced with the 42RE through 2006.)

 

My experience is that in 1987, their first year, the trans shifted 1-2-3-3Lock-ODUnlock-Lock.

It was considered too "busy" so in 88 they changed the TCU to work this way:
1-2-3-OD-Lock.

Now, with the shifter selecting 3, I'll have to go for a drive and report back.

 

So much information! But I learned something new about the ratios and all that. I just always thought overdrive was a really low gear, I had no idea that it was anything over 1:1. Now I know why mine shifts like 5 times before it gets to the final gear. I just always thought it didn't know what gear to get into. I actually got a little on edge because I thought it was slipping. Good to know its workin fine now! And I hate to thread jack, but since we're talkin about these, what fluid do I put in mine when I go to change it? My dad said Dextron 3 but he wasn't sure. It could use a change, its kinda burnt smelling and not too red anymore.

 

Dexron is what you want.

And do this and see how you like it.
https://www.cherokeeforum.com/f2/free-quick-fix-41821/

Is your Power/Comfort switch in the Power mode? And if it is, is it lit up?

 

But aren't there different variations? I don't wanna run a different number in and mess up the tranny.

 

And yes, my power switch is on and working. I should do that adjustment today actually.