I need some help with my cars trans it's a 700r4 the case has MD8 marked on the passenger side the smaller imput shaft is 30spline the bigger spline on the shaft is a 27spline and the output shaft is a 27 spline I'm looking for a rebuild kit for my trans and some say for 27spline only or 30spline only which spline count do I use this is my first trans rebuild iv ever attempted so I will have a lot of noobish questions oh the trans ID number is 7YPM159B

 

No takers ?

 

A 1987 should be 30 splines pump shaft

 

If the counts are correct then an older one has been swapped in. There is a date code stamped into the passenger side of the case, just above the pan, toward the rear. 27-spline inputs aren't worth rebuilding. And you go by the larger part of the input.

 

Drop the pan, look for the auxillary valve body. If it's not there, find another trans. Save your tailhousing and your speedometer gears, your governor and your throttle valve cable. This way your replacement can be from a Caprice, a C1500, or whatever else.

 

This is the number from the trans is 7YPM159B and from what I be able to find its a 1987trans and ill post a pic of the tranny

 

this is what im talking about for the bigger and smaller splines



Also I found the best tools for working on these cars ratchet wise are the craftsman pass trough ratchets the head is slimmer and made it less pain in the a** removing the tranny

 

I can take the pan off and take a pic and post it for you guys

 

this should help http://www.hotrodders.com/articles/T...ification.html

 

According to that my trans is a 87 but it looks just like the Side of the 89

 

here she is just waiting for a new trans

 

The trans in the pics is the later design auxiliary valve body trans ... external indicator is the "cam lobe " casting line on the pass side by the servo and cooler lines ... with the pan off the most visible indicator is the pipe that feeds oil from the pump to the aux valve body at the rear of the trans ...........

 

That is a 30 spline input shaft. Take a micrometer or calipers to asure yourself that it is a 30 spline input shaft. The shaft diameter will be .990" +/- .005". The 27 spline shaft will be .890" +/- .005". Remember it is the shaft that turns you are looking to check out here.

 

Thank you the smaller shaft is a 30spline

 

Ok my dad was checking the trans out today and pulled the gov and the gear on it well lets just say half of its gone

 

That is common, all you end up with is 1st & reverse. Easy fix to install a new gear.

RBob.

 

That's all I Had was 1st and reverse I called and asked everywhere and I was told by everyone I needed to pull trans and rebuild it. Iv already ordered my new gear ill post a pic of the old I'm still going to go through the trans and make sure everything is good and doing new gaskets

 

what i don't understand is why make the part plastic if its so important ?

 

Do they make a metal one?

 

I have been looking all day and can't find one

 

Usually they wear into an apple core shape. At which time they no longer engage the gear on the output shaft.

I've never seen one that actually had the teeth break off. Wonder if something got caught in the teeth to cause them to break.

See what's in the pan, may provide a clue.

RBob.

 

Maybe someone pulled it strait out not letting the governor rotate while pulling it out.

 

When I first pulled the pan I checked for any thing that shouldn't belong and it was normal it had some metal dust but no plastic chunks or metal chunks also my trans only had 1st and reverse gear so I'm going to replace the gear and pray that's what it was

 

I can't be 100% sure I bought the car with the trans the way it was the car had 66k original miles on it. it was my first car and other stuff came up and all I got a motorcycle and just now getting around to the car a year later. But the good thing is the car had all new fluids,brakes and tires put in oh and t-top seals

 

But guys thanks for all your imput and help alotta people don't give credit where it's due and the site has helped me out on so many things i wouldn't have been able to figure out on my own