2 Wheel Drive To 4 Wheel Drive Conversion

[Pete M]

don't forget the linkage brackets, especially the body side one. 

 

cost me $30 to get my driveshaft cut down.

[Pete M]

oh, and another benefit of buying a post-86 XJ is a stronger front driveshaft.  earlier ones were pretty wussy.  post-94 should get you the bigger U-joints in the front axle.

[redwolf624]

Got it pete, so go 94 or new for the front axle and drive shaft?

 

Redwolf

[mvusse]

Do not get 2000 or 2001. Those were low pinion.

[TheDirtyJeep401]

Didnt they change speedo cable to a electric one in like 90 or something? or am I just thinking of things? 

[BIGHEEP]

Didnt they change speedo cable to a electric one in like 90 or something? or am I just thinking of things? 

It doesn't matter the t case housing is the same.

[TheDirtyJeep401]

 

Didnt they change speedo cable to a electric one in like 90 or something? or am I just thinking of things? 

It doesn't matter the t case housing is the same.

I know, it just if he was going to do a swap, he would need that too.

[GirsMJ86]

There isn't anything more he would need though since his speedo cable will work even on the electronic speedo t-case.

 

I guess I should have specified what I meant a bit better? I just was starting there was nothing more he would need since the t-case setup for electronic output by wire is no different than the ones that use the cable. You essentially just yank out the one connector and swap for the other no matter new to old or old to new t-case.

 

That still isn't worded well... I'm going to bed.

[Eagle]

There is no "electronic speedo t-case." The transfer case is the same. What changed is the output --  the "thingie" that gets inserted into the transfer case with the plastic gear on it.. The output for a mechanical speedometer is a cable. The output for an electronic speedometer is a wire.

 

97+ (or 96+) transfer cases are less desirable because Chysler changed the output to a long, unsupported shaft that's prone to vibrations. It has the advantage of being sealed, so if you remove the rear driveshaft the fluid doesn't run out -- but that's the ONLY good thing about it.

[TheDirtyJeep401]

That still isn't worded well... I'm going to bed.

I need to, can't think straight when I'm tired. 

[Blue88Comanche]

I thought a longer speedometer cable is needed to reach the TC.

[mvusse]

There is no "electronic speedo t-case." The transfer case is the same. What changed is the output --  the "thingie" that gets inserted into the transfer case with the plastic gear on it.. The output for a mechanical speedometer is a cable. The output for an electronic speedometer is a wire.

 

97+ (or 96+) transfer cases are less desirable because Chysler changed the output to a long, unsupported shaft that's prone to vibrations. It has the advantage of being sealed, so if you remove the rear driveshaft the fluid doesn't run out -- but that's the ONLY good thing about it.

 

Even on the internally lubricated output shafts the shaft is the same length and the bearing is just as far back in the case. No personal experience with the vibrations you talk about, but I think it is more likely because people do not keep the slip yoke greased. The only two cases I have had like that are a 1998 242 out of a ZJ that was under Sparkles until last week, and a loaner 2000 231 that is under it now, both with a hack-n-tap sye.

 

On a side note, on a 231 the front output shaft is 26 spline and smaller than the 27 spline rear output shaft. A 242 on the other end has a huge 32 spline front output shaft and the same 27 spline rear output the 231 has. The heavy duty 231 sye kits (I have one in Wilbur) replace the rear output shaft with one having the same 32 spline output the front on a 242 does.

 

And on a second side note: Tom Woods has a great warranty on their drive shafts, and people who have run them have been happy with them. But I will never buy a 242 with a sye from him. It is a hack-n-tap, but instead of using a custom 27 spline yoke, he turns the shaft down and cuts new splines to be able to use a 26 spline front yoke meant for a 231.

[Alexia]

I would take a 1996+ transfer case over the old design any day. The tail shaft oil seal and bushing in the older transfer cases will not stop any vibrations that can be felt in the cab. If there is enough vibration to be felt there is a problem with the drive shaft or a worn output bearing.

[Eagle]

Even on the internally lubricated output shafts the shaft is the same length and the bearing is just as far back in the case. No personal experience with the vibrations you talk about, but I think it is more likely because people do not keep the slip yoke greased.

 

Nope, the vibration is a result of u-joint angle combined with unsupported length of tailshaft. It affected ALL XJs with the Up Country suspension. I know -- I own two of them. I discussed it with the service manager at the dealership where I bought them, and he admitted that his wife's '99 XJ had the same problem. The factory did offer a "fix." Not a short shaft conversion, which would have been a real fix. No, the factory wanted to just install a transfer case drop to change the u-joint angle.

 

The vibration isn't too bad on my wife's 2000 with the 242 transfer case, so I'm not worried about that one. My 2000 5-speed has a severe vibration, so I baby it when driving, and I have a short-shaft conversion sitting in the garage waiting for the day (week) when I can find the time to install it.

 

The output shaft lubrication issue causes a different phenomenon -- a short of "lurch/bump" feeling coming from the drive train just as forward motion stops when driving and then stopping (such as a t traffic lights). I get that a lot more in the 2001 than in either of the 2000s.

[Oyaji]

 

 

Even on the internally lubricated output shafts the shaft is the same length and the bearing is just as far back in the case. No personal experience with the vibrations you talk about, but I think it is more likely because people do not keep the slip yoke greased.

Nope, the vibration is a result of u-joint angle combined with unsupported length of tailshaft. It affected ALL XJs with the Up Country suspension. I know -- I own two of them. I discussed it with the service manager at the dealership where I bought them, and he admitted that his wife's '99 XJ had the same problem. The factory did offer a "fix." Not a short shaft conversion, which would have been a real fix. No, the factory wanted to just install a transfer case drop to change the u-joint angle.

 

The vibration isn't too bad on my wife's 2000 with the 242 transfer case, so I'm not worried about that one. My 2000 5-speed has a severe vibration, so I baby it when driving, and I have a short-shaft conversion sitting in the garage waiting for the day (week) when I can find the time to install it.

 

The output shaft lubrication issue causes a different phenomenon -- a short of "lurch/bump" feeling coming from the drive train just as forward motion stops when driving and then stopping (such as a t traffic lights). I get that a lot more in the 2001 than in either of the 2000s.

Eagle - what's the lubrication issue? That the splines on the output shaft and inside the slip yoke are not in a bath of 90-weight? And if that, are the splines binding and wearing for lack of lubrication?.

.

If so, seems like the addition of a grease zerk and the occasional shot of grease through it into the slip yoke might fix that? It works for other driveshafts on much heavier equipment... or maybe I am misunderstanding your description of the problem.

[mvusse]

I have never owned an Up Country. Every Cherokee I have driven sitting higher than stock either had a transfer case drop or a sye.

 

As far as lubrication, the earlier transfer cases lubricated the slip yoke internally. As in the transmission fluid from the transfer case kept it lubricated with an oil seal arounf the yoke to keep the fluid from leaking out. On the newer transfer cases the output shaft is sealed and the slip yoke is lubricated with grease, with a rubber boot over it to keep the grease from being flung off.

[Oyaji]

I have never owned an Up Country. Every Cherokee I have driven sitting higher than stock either had a transfer case drop or a sye.

 

As far as lubrication, the earlier transfer cases lubricated the slip yoke internally. As in the transmission fluid from the transfer case kept it lubricated with an oil seal arounf the yoke to keep the fluid from leaking out. On the newer transfer cases the output shaft is sealed and the slip yoke is lubricated with grease, with a rubber boot over it to keep the grease from being flung off.

Exactly as I expected and described - so what is the problem with lubrication then? The grease is not up to the task? Or there is no easy way to add more? If so, that was why I proposed adding a grease zerk.

.

Otherwise, what sort of grease is used to lube the splines? Maybe a swap to a specialty grease would help - like CV joint grease - its molybdenum content and high-pressure qualities might alleviate the problem. Another alternative would be universal joint grease, if you can get it - it is a specialty high-pressure grease also. U-joints fail without it, and that is the reason that manufacturers no longer incorporate grease zerks: the special grease they are assembled with is not generally available and regular grease isn't up to the task, so nowadays they come with no zerk to add grease so as to not adulterate what is packed inside from the factory.

[redwolf624]

now 42 replies and it's not even my fault  :yes: i do have another question though, i heard somewhere that i'd have to change the engine if i was to convert my MJ to 4wd, i don't know if that's true or not but if it was to be true, why would i have to change it?

 

Redwolf

[Eagle]

Eagle - what's the lubrication issue? That the splines on the output shaft and inside the slip yoke are not in a bath of 90-weight? And if that, are the splines binding and wearing for lack of lubrication?.

.

If so, seems like the addition of a grease zerk and the occasional shot of grease through it into the slip yoke might fix that? It works for other driveshafts on much heavier equipment... or maybe I am misunderstanding your description of the problem.

 

The issue isn't wear, but an odd sensation that's difficult to describe unless you've felt it. I first encountered it in my ill-fated 1999 WJ, and I now have it in the 2001 XJ Sport (which does NOT (yet) have Up Country suspension). As you slow to a complete stop, the vehicle seems to stop normally and then, just as the wheels come to a complete stop, there's a sudden lurch almost like a car came up behind and gently tapped your bumper. It seems to be caused by the splines in the slip yoke binding as the suspension moves, then releasing abruptly when motion has stopped and the suspension settles.

 

With the '99 WJ the dealership (and then the factory rep) told me that using a new, special grease on the slip splines would cure it. It didn't. With the XJ, the rear springs are noticeably sagged, and I expect that when I add a second main leaf to bring the ride height back up to where it should be that the stiffer rear springs will reduce spring wrap under braking and hopefully eliminate the issue.

[nitroxsteve]

now 42 replies and it's not even my fault  :yes: i do have another question though, i heard somewhere that i'd have to change the engine if i was to convert my MJ to 4wd, i don't know if that's true or not but if it was to be true, why would i have to change it?

 

Redwolf

You don't need to change the engine.

[gogmorgo]

The 2.8's are known for reliability issues, low power, and poor fuel economy, but that's the only reason anyone would recommend changing it. So long as you can find a tranny and tcase to bolt onto it, you're good.

[Oyaji]

The issue isn't wear, but an odd sensation that's difficult to describe unless you've felt it. I first encountered it in my ill-fated 1999 WJ, and I now have it in the 2001 XJ Sport (which does NOT (yet) have Up Country suspension). As you slow to a complete stop, the vehicle seems to stop normally and then, just as the wheels come to a complete stop, there's a sudden lurch almost like a car came up behind and gently tapped your bumper. It seems to be caused by the splines in the slip yoke binding as the suspension moves, then releasing abruptly when motion has stopped and the suspension settles.

 

With the '99 WJ the dealership (and then the factory rep) told me that using a new, special grease on the slip splines would cure it. It didn't. With the XJ, the rear springs are noticeably sagged, and I expect that when I add a second main leaf to bring the ride height back up to where it should be that the stiffer rear springs will reduce spring wrap under braking and hopefully eliminate the issue.

.

OK - the binding issue is as I guessed. I expect that adding a leaf will help, but won't cure the problem, because the lurch you feel is under deceleration, and axle wrap is far less an issue then than under acceleration. Getting stiffer front springs might help more, since the weight shift forward under braking causes the rear to rise while the rear end stays on the ground, causing a driveline geometry change that has your yoke sliding out a bit and binding upon return to level unloaded suspension position.

.

That doesn't fix the root cause. Though having the annoyance go away will probably restore your peace of mind to some degree, if you are like me then you will still be bugged by the knowledge that there is still something inherently wrong with the design...

Eagle, on 26 Sept 2013 - 21:07, said:

97+ (or 96+) transfer cases are less desirable because Chysler changed the output to a long, unsupported shaft that's prone to vibrations. It has the advantage of being sealed, so if you remove the rear driveshaft the fluid doesn't run out -- but that's the ONLY good thing about it.

.

So what is the vibration issue? I was guessing wear would allow the yoke to wobble a bit on the splines, thus causing vibration.

.

I see Chrysler had the grease idea, but I wonder if the dealership packed enough inside the yoke. I also wonder if they used molybdenum CV joint grease, and if it wouldn't be a good alternative, and if a couple shots through an added grease fitting every so often wouldn't help even more.

[Eagle]

 

.

So what is the vibration issue? I was guessing wear would allow the yoke to wobble a bit on the splines, thus causing vibration.

.

I see Chrysler had the grease idea, but I wonder if the dealership packed enough inside the yoke. I also wonder if they used molybdenum CV joint grease, and if it wouldn't be a good alternative, and if a couple shots through an added grease fitting every so often wouldn't help even more.

 

The vibration issue is basically tailshaft "whip" resulting from too much u-joint angle and load.

 

The problem carried over to the Libertine, too, and Chrysler still didn't just do a short shaft transfer case with the slip joint in the driveshaft. On the Libertine, they hung a heavy, concentric weight on the driveshaft to dampen the vibration, neatly addressing the symptom rather than the cause.

[redwolf624]

 

now 42 replies and it's not even my fault  :yes: i do have another question though, i heard somewhere that i'd have to change the engine if i was to convert my MJ to 4wd, i don't know if that's true or not but if it was to be true, why would i have to change it?

 

Redwolf

You don't need to change the engine.

 

 

The 2.8's are known for reliability issues, low power, and poor fuel economy, but that's the only reason anyone would recommend changing it. So long as you can find a tranny and tcase to bolt onto it, you're good.

alright that makes since, and as far as the 2.8 havin low power and poor fuel economy, for as little as that engine it it has a lot of power and i get 17-19 miles to the gallon  :banana:

 

Redwolf

[GirsMJ86]

When you consider though that it is a V6 rather than a 4cyl, that power and such is very weak. It makes the exact same power and the 2.5L which is a 4cyl. Well okay, not the EXACT same power since I believe it had 7hp less than the 2.5 with only marginal gain in torque of 15 or so. It also has a 2bbl carb rather than TBI like the 2.5. For reference the 2.5 made something like 117hp and 135 torque.

 

Compare that to the 4.0 the next year which added 63hp to the 6cyl offering (173hp), fuel injection, better fuel efficiency, and 220 torque.

 

And of course both the 2.5 and 4.0 are very reliable and can go over 300k without being rebuilt. Doubt there is a single 2.8 in existence that has pulled that off.