What to do with mystery 700r4 's? Best inspection procedure?
 

Hello all,
I have 2 700r4 trannys that I pulled from an 88 and 89 Formulas both with non running 350s.
I have installed and removed several auto trannys and replaced filters, but never opened or dissected one beyond that. I have rebuilt manual trannys and transfer cases.
Both cars were bone stock, around 170k miles with original drivetrains. The 88 seemed to have some lower end carnage in the motor (haven't got it apart yet, but sounded like a banging rod) and the 89 has very poor and uneven compression and wouldn't start due to wiring hacks anyway.
Both cars have been sitting for at least 2 years. Both had dirty but seemingly uncontaminated fluid at decent levels and no obvious leaks. Both shifted through drive, reverse, park when pushing the cars around.
What do you think is the best way to check these out? Or should I just give them both to a shop for total rebuild?
Thanks
Peter

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

imo you have two choises.install it and see if its good or have it rebuilt.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

You can do a little exploritory surgery like pull the pump and check it out and pull the tailshaft and check the bushing but with 170k and semi burnt fluid I wouldn't bother putting them in a car unless I was flat broke or want practice r&r trannys. 50k is usually my limit to what I will put back in a car or truck. After that its a craps shoot.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

pull the pan and see if there is clutch material.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

Thanks guys,
Can you see the clutches with the pan off?
I agree that with 170k they would be risky, but it's possible at least one has already been rebuilt. When I pulled the tranny off the motor yesterday I found the torque converter had "blue formula" written on it which implies it was removed at some point.
Any other obvious markers for a previous rebuild?
All my cars are manuals and I can't drive an f-body here in winter anyway. I think I'll have one rebuilt by a shop unless I can see its been recently redone. Maybe I'll just part the other one out since I only need one auto for my projects.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

How clean does the outside look and are there any leaks. That isnt very scientific but will 170k on it is should be dirty and have a few leaks. You cant get a look at any of the clutches unless you pull the pump and get into the guts. When you pull the pan you can look at the clutch material that has worn off the clutch plates. Since both have dirty fluid they should have some material built up in the pan.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

Use the 89 trans for your build as that was a year for some good factory upgrades.
Do a search for where to buy or have your core built. I'd suggest Dana at probuilt.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

Yes, I think that's how I'll do it since the 89 will have original drivetrain w matching #s. I've heard lots of good feedback about Dana, I'll have to give him a call for some pricing.

Neither tranny seem to have any significant leaking, both are covered in oil from blown rear main seals in the motors.

I think I'll use the 88 as a guinea pig and tear it apart to see how it works and part it out if there's a lot of wear.
Appreciate the input folks.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

You could see if the tranny shop would give you any credit on the other 700 for a core. I use to know a tranny shop that would give you a few bucks. Or tear it apart. if there are any trashed parts in the 89 use the parts out of the 88. then strip the case and get lunch money from the scrap yard.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

Pull the pan its very easy and like 13 bolts or something. The fluid should be red with just a little clutch material in it with normal wear and tear (thick dark gray sooty material. If you have clutches going out it will saturate the bottom of the pan and you will be able to write your name in it.

That is the first inspection I recommend, if you find a abnormal amount clutch material it deserves a closer look.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

Just rebuild the late model tranny and while you are there repalce the TC, as the tranny gets older and the clutches ware out that crud will get into the TC and could cause problems down the road.

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

Not that I would use their products, but here is some good info....

http://www.transmissioncenter.net/700r4.htm

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

Very informative link,thanks!

Re: What to do with mystery 700r4 's? Best inspection procedure?
 

agreed.