Driveline vibration only in 4WD? (4.5" lift, '92 XJ)

I have searched, and there's much mention of driveline vibration, but I haven't seen anybody specify (or I'm just blind) whether or not the driveline vibration is across the ranges (2WD all the way to 4LO) or whether it is exclusive to 4WD. So here goes.

I just bought a '92 XJ with a 4.5" RC lift yesterday as a winter beater. It's got its problems that I intend to MacGyver with some friends (loose steering column, sagging seat stuck at 45o recline). But I have two or three real problems. edit: it's 5-speed, but I have no idea which transmission, which diff, which axles, etc. sorry!

In 2WD, the vibrations are very minor. I don't know if this vibration is just typical behaviour as I'm used to driving a little sports car, so I'll just throw that note out there: the vibrations seem okay in 2WD, if not maybe expected for a lifted Jeep.

However, shifting into 4HI, from 40+km/h, the vibrations are intense. Like, thud-thud-thud-thud-shaken-not-stirred-martini. It's nuts. I wouldn't call it death wobble because as far as I understand that's a suspension resonance issue? But it's deathly annoying and certainly not good.

I imagine that it will be needing an SYE, as it has the band-aid t-case drop at the moment, but the real question is: with a lift and without the SYE, wouldn't the Jeep be vibrating badly in 2WD as well? Because of the intensity of the vibrations I can't tell if it's coming from up, down, side to side, wherever. It only happens this badly in 4WD. And that has more to do with the front diff, not the rear linkage, right? Correct me here.


Any help would be appreciated. Greatly.


(oh and mini issue: knocking sound from low left driver side, intensity/frequency dependent on actual vehicle speed not engine RPM, stops if I lock up tires (in snow), so would that be a wheel bearing?)

I just bought a '92 XJ with a 4.5" RC lift yesterday as a winter beater. It's got its problems that I intend to MacGyver with some friends (loose steering column, sagging seat stuck at 45o recline). But I have two or three real problems. edit: it's 5-speed, but I have no idea which transmission, which diff, which axles, etc. sorry!

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Transmissions

Manual Transmissions
T4 & T5 - 4 & 5 speed manual - manufactured by Borg Warner - used 84-86 with 2.5L I4 and 2.8L V6 engines
BA10/5 - 5 speed manual - manufactured by Peugot - used only up to 89
AX5 - 5 speed manual - manufactured by Aisin - used with 2.8L V6 and 87+ with 2.5L I4
AX15 - 5 speed manual - manufactured by Aisin - used with 4.0L I6 engines
NV3550 - 5 speed manual - manufactured by New Venture - used in 00-01 in SE models with 4.0L I6 engines

Automatic Transmissions
Torqueflight 904 - 3 speed automatic - used 84-86 with 2.8L V6 and 2.5L I4 engines
30RH - 3 speed automatic - used with 2.5L I4 engine 94?-00
AW4 - 4 speed automatic, electronically controlled - manufactured by Aisin - used from 87-01 (87-91 models include a Power/Comfort button that adjusts the shift points)

Axles

Front Axles
Dana 30 high pinion - reverse cut - 27 spline, 1.16" diameter shafts, 7.13" ring gear - used 84-99 (some axles through 91 are vacuum disconnect, 92+ are non-disconnect, 89-95 with ABS have 5-297x u-joints, all 95+ have 5-297x u-joints, all others have 5-260x u-joints)

Dana 30 low pinion - standard cut - 27 spline, 1.16" diameter shafts, 7.13" ring gear, 5-297x u-joints - used 00-01

Rear Axles
Rear Axle pics including non stock ford 8.8 and 9" and D60- http://memimage.cardomain.net/member_images/1/web/325000-325999/325707_182_full.jpg
(Note on Dana 35 axles sometimes referred to as Dana 35C - The "C" does not stand for c-clip. It stands for "custom" meaning it came from Dana unfinished.)
(Note on 8.25 axles - none of these axles were used on XJs with ABS brakes. If you have ABS, you have the Dana 35. Without ABS you could have either axle. 8.25 axles are c-clip)

Dana 35 non c-clip - 27 spline, 1.18" diameter shafts, 7.58" ring gear, 2.62" axle tube - used 84-89
Dana 35 c-clip - 27 spline, 1.18" diameter shafts, 7.58" ring gear, 2.62" axle tube - used 90-01
Chrysler 8.25 - 27 spline, 1.17" diameter shafts, 8.25" ring gear, 3" axle tube - used 91-96
Chrysler 8.25 - 29 spline, 1.21" diameter shafts, 8.25" ring gear, 3" axle tube - used 97-01
Dana 44 non c-clip - 30 spline, 1.31" diameter shafts, 8.5" ring gear, 2.75" axle tube - used 87-89 on some(not all) XJs equipped with towing package

Id bet that either a front u joint is bad or the cardian joint. You could benifit from an sye for your 2wd vibes however a sye doesn't effect the front shaft... get under there and take a look at the u joints check the for play as well as check the cardian joint.. you may have to pull the front shaft to do so..

JRW7072009 said:

Transmissions

Manual Transmissions
AX15 - 5 speed manual - manufactured by Aisin - used with 4.0L I6 engines


Axles

Front Axles
Dana 30 high pinion - reverse cut - 27 spline, 1.16" diameter shafts, 7.13" ring gear - used 84-99 (92+ are non-disconnect,)


Rear Axles
Rear Axle pics including non stock ford 8.8 and 9" and D60- http://memimage.cardomain.net/member_images/1/web/325000-325999/325707_182_full.jpg
(Note on Dana 35 axles sometimes referred to as Dana 35C - The "C" does not stand for c-clip. It stands for "custom" meaning it came from Dana unfinished.)
(Note on 8.25 axles - none of these axles were used on XJs with ABS brakes. If you have ABS, you have the Dana 35. Without ABS you could have either axle. 8.25 axles are c-clip)


Dana 35 c-clip - 27 spline, 1.18" diameter shafts, 7.58" ring gear, 2.62" axle tube - used 90-01
Chrysler 8.25 - 27 spline, 1.17" diameter shafts, 8.25" ring gear, 3" axle tube - used 91-96

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Those are my guesses. I'll have to check the rear axle to narrow down between the two rear axles. Is the Dana 35 c-clip axle better than the Chrysler?

Thanks for the info, JRW7072009.


You think a front U-joint would cause that much intensity in vibration? I'll get it up high and take a look around. The cardian joint I'll have to do a bit of research on. Thanks much, 89XJPioneer. I've got a friend with a hoist so I'll see if I can bribe him into helping me out this week.

Thanks guys. Any other suggestions would be welcome, too.

Alot of member have issues with the Dana 35, calling them time bombs.

Chrystler axle is similiar in strength as the Dana 44, a little less.

Is the front axle a disconnect or not? If it's a disconnect housing then the front driveline is not turning in 2wd, which would point to a problem with the front driveline if it vibrates only in 4wd.

If it's not a disconnect housing then the front driveline turns all the time. If the problem is only in 4wd then it still could be a very bad driveline joint, but you need to be looking for bad parts. It's pretty simple to pull the front driveline out and drive it to see what happens. If the problem is gone, then you know it's the driveline.

Goatman said:

If it's not a disconnect housing then the front driveline turns all the time. If the problem is only in 4wd then it still could be a very bad driveline joint, but you need to be looking for bad parts. It's pretty simple to pull the front driveline out and drive it to see what happens. If the problem is gone, then you know it's the driveline.

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X2. Since you're new to XJs - those little bolts on the double cardan joint at the transfer case end of the front DS look like 8mm, but they're 5/16". Buy yourself a 5/16" gearwrench for $13 and be careful and those bolts will give you no sweat. A deep 5/16 or 8mm socket works great for the bolts on the straps at the pinion yoke.