a rear main seal job as you know is major job and is to be avoided at all costs until it can not.

i have done half dozen and have always done this first before concluding no other choice was possible. for every one done 3 have not had to be thanks to this liquid

look for a bottle of AT-205 re-seal and follow the directions exactly.

https://www.ebay.com/itm/ATP-Re-Seal-8-oz-AT205/132373012185


you will know within a few hundred miles if it is going to help you. it is very effective if the seal is largely in place and not physically damaged but merely dried out and a bit worn. this liquid helps to swell old seals and does a first rate job.

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if you are forced to do the seal and do not have a lift it is a tough job.

you choices are these:

1. pull the engine WITH the transmission attached and reinstall same. much more work and much much longer but oddly enough less stressful since its a one step out and one step in after all the stuff is detached

or

2. drop the transmission alone. this is not hard on the removal but can be VERY difficult to align the bellhousing with the back of the engine on the install and extremely hard if you do it alone. the difficulty stems from the fact you have insufficient clearance without a lift to do the job efficiently as you will see if it comes to that.