New Refurb Engine Vibration

Greetings,
Non mechanic here. Recently had a refurb engine put in my 2000 Tacoma 2.7; runs good but there is some very annoying intermittent vibration that wasn't there with the old engine. Installer says nothing can be done about it and a different mechanic/shop says 15 hours of labor to possibly fix issue. Third mechanic charges $100-$300 just for diagnosis. Difficult to describe vibration in writing, but it makes the dash loudly vibrate intermittently at certain RPMs. Just casting out the line here to look for a different opinion of how to solve the issue.
Much thanks.

 

A little more info on your truck would help? Does this happen when in park or neutral? Any variables that enhance the vibration?

 

Much thanks.
Truck is a manual; happens sometimes when I come to a stop light, at idle in neutral; visible noticeable vibration. Not so much at cruising/non accelerating speeds. Seems to happen most right AFTER accelerating in lower gears; i.e. accelerating in 3rd then letting up on gas.

 

Does I happen when standing still? If not Have you checked your u joints by chance?

 

I would ask this mechanic / shop to explain what they think the issue is. Did you take the truck to them? or is that just a over the phone diagnosis?

There are some really smart folks on this site, but vibrations are nearly impossible to diagnose online.

 

Yes, understandable. This mechanic drove it around the block (free). I am forgetting the terminology he used; but I believe he said it is possibly related to motor mounts.

 

Yes, sometimes at stop lights. Also after accelerating at lower gears.

 

If I were in your shoes, I would be looking up information on how to confirm that it's the motor mounts.
https://youtu.be/g_4DiywsSbk?si=CN7k28ksVvQ28iVo