[6D6GOAT]

So i thought i would try to rebuild a 700R4 for my step sons 66 pickup. its a newer model 87 newer with the auxiliary valve body. to do the rebuild i bought a DVD on ebay. all has gone to plan except for the 1-2 accumulator housing. the video shows a piston and spring. this transmission dosent have a spring. instead it has 2 pistons ??? is this part of an aftermarket shift kit or something?

i also noticed that the pressure regulator valve in the boost valve has a modification. pasrt of the valving has been ground flat on to sides.

[Cliff R]

http://www.cliffshighperformance.com/buy_book_T.html

There were several differnt set-ups used for the accumulators. Two pistons stacked together would disable accumulator function, and would be part of a home-modification.

I like to leave the accumulators functional on the 4L60's, especially for the 1-2 shift as the band is grabbing a drum.

Grinding the flats is OK as long as they ground the correct ones.....Cliff

[69camarox]

grinding the flats on the pr valve is to stop pr buzz at idle in gear . very common mod on 700r4

[6D6GOAT]

cool, thanks guys. i found the PR valve mod online. looks like the previous owner did it right. i also ordered a 1-2 accumulator spring. Cliff, i bought your book a while ago but for the life of me i cant find the damn thing now. lol

[6D6GOAT]

what do you think about the overhaul tips on this guys website...scroll down to the "700R4 overhaul tips" are they worth doing?

[6D6GOAT]

oooooppps... i forgot the link... http://www.montecarloss.com/SSThunder/drivetrain.html

[Cliff R]

The best thing you can do for the 700-R4 is to follow what GM did for them thru the years of production. They continued to upgrade those units, until they got the weak spots worked out, and combinations of parts to make them reliable.

Upgrading to the later or latest set-ups is recomended. I use, and prefer the later 4L60E style molded apply pistons, and high energy frictions. They also went to a much better clutch pack arrangement for the 3-4 pack, with thick apply plates, thick steels, thick high energy frictions, etc. This will be the most durable set-up.

I'd use caution drilling on the separator plate without specific guidence/experience. Several companies make excellent shift kits for the 4L60's, the better kits come with springs for the accumulators, and very specific guidence or where to drill and how large, depending on what your are doing, and exactly which unit you are working with.....Cliff

[6D6GOAT]

ok, thanks Cliff.

[6D6GOAT]

just an update and tip for any newby rebuilders...

i rebuilt the transmission and installed it. i put it up on jackstand topped off the fluids and tried to put it in REVERSE aaaaannnnd....nothing..actually the rear tires moved forward for a second. the rear tires felt like the trans was in N. so i put it in DRIVE and they started to move then petered out. if you rev it for a second it will get the tires moving but were very weak. so i google " rebuilt 700r4 no reverse " and to my surprise there were pages of topics. i started reading and someone mentioned that the boost valves will blow out if you dont get the C clip in the second slot.... second slot? i said to myself. i dont remember that. so i pulled the pan and what do you know. there were all the boost valves sitting there. i was able to look into the bore and see what i did wrong. i simply tapped the C clip until it hit the chambfer. i guess the friction was enough to hold them all in place until hydraulics blew them out. so i reinstalled the boost valves...put the C clip past the chambfer and into its groove. works great now (knock on wood). im so stoked

cheers

[Steve Barcak]

Just following up on how your trans is working and how many miles on it. Have you done any towing with it?