remove the battery tray for even more access. this job should be easy to do from the top, really. you may have to move the transmission filler tube out of the way (gently move it). might seem like a weird question but are you large? i can slide under the car in that area and access the bolts without jacking the car up, if needed. if you're having trouble with the allen bolts, slip the allen wrench through a gearwrench so you can ratchet it out. when the bolts are loose you're going to rotate the starter to vertical in order to pull it out from above.

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1981 NA 300D 310k miles