I have a 2.5L Auto YJ that has just recently developed a bad vibration under acceleration between 31 & 35 miles per hour if I take my foot off the gas it stops completely. It developed Tues of this week. Anyway I took it to a trusted mechanic we have worked with for years, he says its my rear pinion bearing, I'm not sure I believe him because all he did was drive it for a few minutes to determine this he wants to charge me 950 to fix it. No noises are coming from rear end, and the only thing I found odd was that the diff fluid is a peanut butter color and has a very foul smell as well as a small leak from the pinion seals. I'm at a loss here so any ideas would be greatly appreciated.
Sound like you may water in your diff fluid also............
Could the water in the fluid have ruined my bearings? Another conundrum on how the water got in there I put all new fluid in it a year ago and I have never been around any sort of deep water. Will have to check the rear shaft after work.
Check the usual. Usually vibration in the seat is the rear of the jeep. Vibration in the steering wheel is the front of the jeep. Start with the obvious. Check for play in that pinion bearing since you were already advised by a mechanic that it is an issue. You need to have the jeep in neutral when you check. You may even need to remove the driveshaft at the pinion to get a good feel.
Otherwise, check for play in your front end components. Ball joints, unit/hub bearings, tie rod/drag link ends, etc...
Got a short break. Went out and strangled a few things under the jeep. The only thing that moved was the transmission a little, I guess the rubber bushings it sits on have give? I have to take it to my garage with a lift tomorrow maybe ill find something. I'll keep you posted, thanks for the feedback so far.
Idk if the trans bushings should be giving. I knw my trans mount is bad that I can literally get under my jeep, grab the tail shaft, and move the transmission side to side. This also explains why upon take off my yj would shutter alittle. If ujoints are possibly failing might want to address that soon . My ujoint that connects shaft to rear axle pinion went bad and I waited too long to replace it. The result was during my 40 mile commute to work around 3:50am my ujoints finally failed which caused my driveshaft to fall out in middle of pitch black nowhere on hwy. Yes I was stranded. My yj is auto too.
"Its a Jeeps World, other 4x4s just get stuck in it."
My 32RH only vibes during acceleration from a dead stop to roughly 10 mph under a good load. If I'm soft on it, no vibes whatsoever. I'm going to change out my rear U-Joint next week to see if that is the culprit. I've asked and asked and never got a definitive answer. So it's about time for me to pull the trigger.
Not much motion in the ocean, but I'm the captain.
Idk if the trans bushings should be giving. I knw my trans mount is bad that I can literally get under my jeep, grab the tail shaft, and move the transmission side to side.
Mine isn't that bad, just a little movement on the bushings but I suppose a little movement with a lot of weight can be to much. Like I said m off today so I'm gonna put the jeep on a lift and see what I can find. Hopefully its not anything real bad. If so there may be a jeep for sale with an extra part to fix the problem. I must have spent 5k on it last year on 4 torque converters and a trans rebuild alone.
if that solves your problem let me know I get the same vibe just at stop to accelerate and If I take it slow it doesnt vibe at all its been that way for 2 years now and no one can tell me for sure what it is, so Im curious if the ujoints take care of your problem, Good Luck