Looking to upgrade trans currently running a 700r4 trans in my 89 blazer, the inner seal is started leaking a couple drops here and there so want to get a better trans for it and was hoping some would have done upgrades to the trans or replaced them already and have recommendations on where to get them from as well thanks in advance.

 

The front seal in the 700-R4 is well known to leak. The upgrade to prevent that is new pump bushing installed along with seal and enlarging the drain back hole to 5/16. Unfortunately transmission has to come out and pump removed to repair. There are numerous articles on the 700 updates and upgrades on the web. Good luck.

 

My advice. . .after a year long battle with my 4l60e to get it fixed. . .is plan ahead here.

You will be happy you did later on. Depending on the state of your trans I would consider having it rebuilt if you take it out for the front pump seal.

Even a partial rebuild with new 3-4 clutches, and 2-4 band would be worth while. There are a ton of Sonnex upgrade parts for these transmissions, and it's just a question of how much do you want to do, and how much do you want to spend.

You could upgrade to a later version. . i.e. 4l60e, 4l80e, but doing so will require you to spend like $700 on a trans controller for the electric trans, and really there is no benefit for you.

I'd recommend pulling the 700R4, fixing what needs fixed, making any upgrades, then put it back in.

If they haven't been done already, upgrading to the bonded clutch pistons is another good thing to do, since they do crack sometimes.

I've got a lot of my trans work detailed in my build thread if you're interested in taking a look. Also, error_401 gave me a great rebuild e-book that I'd be happy to send you if you need it.

 

That would be awesome I actually ordered a new trans and am gonna have this one rebuilt the shop I got it from didn't hit me with a core charge so 😁 but on the rebuild will definitely look into it, the diff gearing seems a lil high to me 3.42 thinking might go a lil lower 3.73 take some of the strain off the trans and motor. But will see after engines built and new trans is put in on how it handles the gearing.

 

Honestly, I kind of wish I'd have just bought a rebuilt unit from Monster. I'm glad I learned everything I did, but I didn't save that much $$ in the end. Would have gladly spent a bit more money to have only had to take the trans out once. . not to mention the piece of mind. Lol I have less confidence in my rebuild vs someone who really knows what they're doing.

For gearing I guess just depends on your use. Not sure which gears I have, I'd almost like to turn a few less rpms at higher speeds, but I want comfortable highway cruising for long hauls.

 

This is my setup like I said diff gearing is a lil hi hates 4th when it comes to hills.
This is what I would like it to be, so two options change fourth gear or change differential gearing but the diff I have right now is lsd.
But yeah tremec toolbox app rocks and has saved me already a couple times. Trust me she does 90 down the freeway no prob and is good on gas the needle doesn't drop like one would expect. But I want something a lil lower. But like I said we will see how it sits after engine mods and upgrades. Block bored 30 over, Edelbrock performer intake with vortec heads still working on what cam I want to go with bouncing between crane and comp cams, hoping with a lil more power and torque she will do a lil better on hills in higher gears.