B2 Runs poorly after drive shaft replacement and oil change

I had my B2 in the shop last week for a quick swap of rear drive shaft and to get an oil change My B2 is an 87 with a 2.9L, 5 spd manual, and manual 4wd transfer case.

Before going into the shop it was running quite well. It made lots of clicking from the rear drive shaft (original OEM shaft in bad shape). The clicking had been going on for a year and was starting to get noticeably worse so decided it was time. Other than that, it was running pretty clean.

I couldn't locate an OEM drive shaft and found mostly what I think are called GKN conversion. In reading about that my understanding is that unlike the original CV drive shaft there could be vibration issues if spline alignment wasn't good?

From what I had read I was attuned to the fact that it might not be as smooth. Despite the audible clicking, when accelerating hard it pushed very smoothly.

I get it back and didn't notice anything I recognize as vibration in normal driving. Under a hard accel however I could feel some vibration in the stick which was more significant than anything but thought if that was it, no big deal.

But at the same time it didn't seem to accelerate as well. It seemed like...a bit uneven, like there was an occasional miss. I kinda dismissed it at the time cause I can get hypersensitive about the feel, but as I have continued to drive it, it very definitely seems like something is off.

I find I am having to downshift more often. It "feels" like it is just hesitating, low power...like maybe the engine is missing. I would say it feels like a break is dragging but it isn't a continuous sort of drag. It is like every second or two the engine misses a bit and hesitates.

My inclination is to think engine, but the diagnostician in me asks makes me think back to the work done. I suppose it could be coincidental, and maybe they poked some wire or sensor while doing the oil change or drive shaft change, but not knowing the in and out of drive shaft change, GKN conversion, I wonder about that change.

If there were a vibration problem from the drive shaft, how would it seem? Would it be continuous and change with speed? Or could it vary, for example oscillate between smooth and vibrating? Like could the "hesitation" I feel be a result of the shaft momentarily vibrating and steeling energy? During this hesitation I feel something, it doesn't jump out at me as vibration per se but I just don't know what to expect.

Then tonight, I checked the oil level to see if there was enough and found the oil level an inch and a quarter above the maximum. I cleaned and re-measured pulled it several times to confirm. The vehicle had been sitting 2 hours so it wasn't hot (if oil could expand that much in a hot engine). It wasn't absolutely level, but it is the best I have and it is pretty close. I been using that spot for years and never seen this in any of my B2s.

So how serious is the oil level like this? Could it explain the engine being hesitant? Is there likelihood of serious damage in the 300 miles I drove since getting the work done?

Any thoughts would be appreciated. Obviously I will drain some of the oil now that I am aware of it. Just wondering if either of these could explain what I am experiencing.

If these could explain the problem, then I focus on them a bit more. If I am barking up a tree and neither could explain, then I can put that out of my mind and dig into engine to find out what may be up.

Here is a pic of the oil level I measured. The level goes up to where 0 is on the lower scale of the ruler.

That is a quart overfilled, which can cause lots of fun running issues.

A drive shaft vibration could be there all the time, it could come and go at certain speeds, depending on what is causing it. A worn u-joint will make noise/vibrate at low speeds but become smooth as you speed up and the ears "float". A locked up one will vibrate constantly getting worse as you speed up until it breaks the shaft. A dented or off balance shaft can come and go, similar to a tire vibration, but more intense.

I would get an open topped drain pan and two clean gallon jugs. Drain your oil, then fill the one container, put it back in the engine. Keep the other one for spare oil.

The 2.9L holds 5 quarts dry, when you drain the engine one quart stays in the filter, so you want to drain the pan and put 4 quarts back in.

Fix your oil level and then see how it runs. With it being that over-filled it might not hurt to pull the plugs and make sure they don't have oil on them.

If it still feels wrong, like it has a driveline vibration post back here and I'll tell you how to balance your own drive shaft for about $10.

According to the bill, the put 5 quarts in it, but the filter was supposedly changed too so shouldn't be an issue unless filter wasn't done, wasn't drained all the way for some other reason, or someone lost count putting the oil in. I dunno, I know when I put oil in, I always am checking the stick after the first few quarts and giving time to settle.

The bill also says they put in 5W-30 instead of 10W-30. Not sure how big a deal that is.

Checking the plugs will be a pain...I've been down this road and find nearly everyone next to impossible to get out because something is in the way of all of them on this particularly BII. On my original 88 B2 I could get at all but one without much difficulty.

Okay, drained the oil and got that straitened out. Pulled one plug and it looked okay...an awful lot of rust on a plug that was supposedly new last year with less than 10K miles...but maybe new plugs rust fast?

Anyway, getting the oil straitened out...even after driving my significantly more powerful 2002 explorer with the V8...the B2 seemed to have shaken the lethargy... A bit surprised it mad that much difference.

I still find the vibration in there however so would be interested in hearing that fix.

Thanks,

Andrea