Internal Reaction (Ring) Gear shattered in 700R4..

[robert213]

The Internal Reaction (Ring) Gear shattered in 700R4 of my 1982 GMC 2500 4x4 with 98K miles.


http://www.geocities.com/pm67/m01horse01.jpg

I have inherited a 1982 GMC 2500 4x4 from my mother. I had automatic trans fluid replaced at 70K miles three years ago. Everything appeared to be normal.

Last week, I put transmission in "Drive", proceeded to step on gas pedal, and heard the most gawd-awful noise I had ever heard.

Local Buick/GMC dealership originally said that I shattered the Sun Gear and Shell in the transmission. I visited the dealership to take a look at the transmission for myself.

Now, I know why they call it the Sun gear. There are three planetary gears that revolve around the Sun gear. From what people have told me, it is very common to experience problems with Sun Gear and Shell. Actually, my Sun Gear and Shell were not damaged.

It was the collar ring with teeth that mate with the three planetary gears. It is offically called the "internal reaction gear". It is now in three pieces. The teeth on the corresponding "internal reaction gear support" were completely ground down.

Upon a closer examination, there was another problem brewing. At one end of the transmission case -- on the inside -- there is a channel for a seal. Something called "low reverse piston". It appears that this is another common problem. This channel becomes jagged and causes wear and tear on the seal. This causes reverse and manual low to fail. My transmission was no exception. My channel was very rough. I was told that the seal is supposed to be square. Mine was very rounded.

So, my parts lists, if I decide the have my transmission rebuilt by local transmission rebuilder...

New Transmission Case
New Low Reverse Piston Seal
New Internal Reaction (Ring) Gear
New Internal Reaction Gear Support
New and Improved, Stronger Sun Gear Shell

Question #1. Should I have my transmission rebuilt or should I purchase a rebuilt transmission or should I purchase a new crate transmssion?

Question #2. Where can I find a rebuilt transmission? a new crate transmission?

Question #3. I have never abused the transmission. Other than the problems that I mentioned, the transmission was very clean -- looked like new to me (as a person with no experience in transmissions). The truck only has 98K miles. Any thoughts as to what caused my transmission to let go?

[magnethead]

I see a trailer on your truck. That's probable cause in and of itself.

[robert213]

Early in its life, it was used to haul horses -- maybe 6 or 7 times per year. My mother never drove faster than 50 mph. Lately, I have been driving the truck on 140 mile round trips at 70 mph -- 4 or 5 times per week. I plan to upgrade the trans cooler.

Anyone have any experience with...

TCI Auto
http://www.tciauto.com/Products/Maxi...nsmissions.asp
GM 1984-93 700R4, 30-spline V8 371400

Bowtie Overdrives
http://www.bowtieoverdrives.com

[grinch4om]

prior to 1987 the 700r4 had weaker internals than after that date. These early trans are prone to failure when any kind of severe load or age. NEVER tow in OD. (unless it's like a 500 lb utility trailer, even then not advisable) a corvette servo for band is a common mod, there are aftermarket ones better, all depends on price. I would buy a crate trans or a known good ,late model used one and have new seals and frictions and steels installed. updated servo,cooler... make sure you flush all the lines before installing new trans, replace the converter! All thet trash is in the converter and you will never get it all out. My 84 trans went pooey after I stuck the 454 in it, worked great with the anemic 305, found one out of an 89 camaro for 75 bucks, had it gone through, super servo, hi stall converter etc, works great! Make sure the tv cable is installed correctly, refer to a manual for adjustment unless trans shop does this for you.

[87 STEPPER]

My orignal tranny in m 87 went south on me at the begaining of this summers HotRod Power Tour and the only thing available on the tour was CompCams they own TCI and i dont like the tranny it doesnt shift firm like it should and it has several leaks and it's comming out soon i got a K-case 700r4 built by a place in Central Fl. called 4th gear it's built to handle a big block.

Anyways i have heard alot of good things about bowtie overdrive if i were you spend the money now and get a crate trans from somewhere you will be money ahead and you will have some kind of warantee with it.

If you can get it specify a K-case when you order it, it's a stronger case or so im told they usually come in the 4x4 trucks.

But i don't recomend TCI.

Good luck

[piecesparts]

It is quite pricey to rebuild a 700 tranny, BUT you would know what is in it then. I have had a coupole rebuilt and we put in the heavy duty clutch packs, the heavier sun gear and planetary pieces and the hardened parts in the valve body. I would say that it is a lot stronger than it was in the past and I am sure of what I installed in it. With a package from someone else, you are only guessing at the quality and quantity of parts.

[robert213]

Good info for those of you still using AC/Delco Duraguard Oil Filters...

http://www.hotrodders.com/forum/do-n...ers-71883.html

[piecesparts]

I switched over to the NAPA Gold filters awhile back and am satisfied with their quality.

[rfmaster]

Robert

700R4 subject has been looked in the past

http://67-72chevytrucks.com/vboard/s...ighlight=700R4

Do not rebuild '82 trany - they are very weak! You can get a high performance tow package built 700R4 for about 1400 to 1700 outright. Installation is usuall pain in the back. Also, you must replace converter and radiator to make sure that all junk is out of you trany fluid system!

//RF

[Jonboy]

ince your vehicle is already at the dealership with the trans out, did they price you one? A SRTA (Service Remanufactured Transmission Assembly) should run about $1600 or (plus labor) and carry a 3year, 50k warranty.

[kwmech]

I have never had any luck with the 'dealer' rebuilds, they last long enough to be out of warranty when they fail. Have the tranny rebuilt at a reputable shop or pick one up from tci or b&m. As mentioned before the '82 trans is junk even as a core. See if you can pick up an 89 or 90 core and have it wired internally for your truck

[Russell]

I've had three seperate 700r4s break in a very similar manner... Most recent is my K5, which also shattered the sunshell's collar. 1st and 3rd only, no reverse, 2nd, or O/D.

There is a heavy duty sunshell available which helps prevent that failure.