I have the original bench seat in my truck and I needed to remove it to get better access up under the dash. I hear ya on the shot back, the left side of my neck muscle also got very tense and soar.
To say the very least my wiper motor install consisted of ripping the motor out two or three times.
1. After getting the motor I got up under the dash and removed the original vacuum motor.
2. Installed new wiper motor and mounted switch. Tested operation before putting on the brand new wiper arms and blades.
3. Put on the new wiper arms and blades. Went to test the motor and the wiper blades would not move. The set screws in the output shaft I guess you would call it for adjustment were loose. So I tried with the limited space to get up in there with a small allen key to tighten them up but it was a no go. So out the motor came again. Got the set screws tightened up and then re-installed the motor.
4. After getting the motor back installed and the arms back on the motor there was something that I failed or notice. When I installed the arms on the motor I did not pay attention to what arm went no what peg on the motor. So when I turned the motor on........instead of my wipers going up! they went down and bent my new wiper arms and blades into the cowl. I was so pissed!!!!
5. After getting back under the dash again I swapped the arms on the motor around and proceeded to test it again after carefully bending my new arms and blades back into shape
this time they operated as normal.
6. After doing some testing I was having some issues with the passenger side under dash transmission arm banging up against the cab wall or peaking out its circular travel and flexing the rod and making a hell of a noise. So the solution to this was to enlarge the hole that was there from the factory. What I mean is there is the main transmission arm hole that connects to the motor then there is another smaller hole about 1/2" behind that hole. I just drilled that out to the correct size and used that hole instead. Now my transmission arm was not peaking out travel on the passenger side. So I decided to do this to the drivers side as well because I was having a simular issue. So I got the drill up to do the drivers side, drilled out the hole and got it on the motor. When I went to test it it got about 1/2 a revolution and the motor locked right up. I guess I didnt drill the drivers side hole straight enough and when it spun it locked up the motor. So after turning off the switch I tried to move the motor manually with my hand but it wouldnt budge. I removed the clips and tried to get the drivers side arm off but I couldnt. So out the motor came again lol.
7. After the drivers side arm issue I ended up using the second hole on the passenger side. Then on the drivers side I used the original hole and just put a slight bend in the arm to fix the issue I was having. I believe I also added some washers to tighten up the transmission arms to motor because they only include the thin white washers. I added I think two washers on each arm then added the locking spring. Then finally mounted the switch AGAIN!! lol.
Well now that I've gone off on a tangent about my install lets get back to your question LOL. On my motor when you turn off the switch at any point during travel the wipers go down to the park position. So i didn't know there was any adjustment there. My wipers go up to 90 degrees +/- as I thought they would.
I purchased my motor from kmstools up here in Canada and the box says counterpart automotive. When I talked with the parts guy I believe he might have said the motor was a re-branded Newport engineering motor. So I'm not sure if that will help you out of not. I've included a couple pictures. Dont forget to tighten your set screws
