Hope You Can Help,

86 K5 Blazer (mild 350, 6"lift, 35" Dick Cepeks, 4:10 Gears, 308/700r4, Etc)

700r4 Was Just Rebuilt Last Year W/ A Beast Hd Shell, Large Trans Cooler And Temp Gauge.

Trans In Drive, Jumped On It To Merge Into Traffic, Rpm's Went Up, Hit Second And Imediately Heard A Loud Bang Noise!!!! Lost All Forward Gears. Thought I Blew Out the Rear End Or Driveshaft, But No Such Luck

Luckly, I Was Able To Drove Home 2 Miles In Reverse.

Any Idea What Broke To Lose All Forward Gears:(,
Reverse Is Ok.

Thanks Big Time...
Gary

Call the guys at Bowtie Overdrives. 760-947-5240

http://www.700r4.com

They specialize in 700r4 transmissions, and we've found them very helpful last year when we had problems.

sounds like the forward sprag gear very common in the 4l60e's and 700r4's

I threw out my 700r4 and put in something more durable. It was less than half the price to build a th350. The trans guys I talked to said he could build up my 700r4 for about two grand, but he'd see me next year for another overhaul. I'd stay away from the 700 if you have a heavy rig or plan to beat on it......my2cw.

Okay, I'll help out until the 700R4 mob comes out of the wood work and then I'm outta here.

Do you have manual 1st? If so, can you shift through the gears...i.e. manual 1st to manual 2nd then 'D' then 'OD'??? Only 1st and 2nd gears use the forward sprag unless the LO/Rev clutch is engaged...i.e. 1st and 2nd if in "drive". If you can shift thru the gears manually then, yes, your forward sprag broke.

thanks 2 all..

hay aaronr10,

1) Does it have manual 1st? Nope..
which then means that my forward sprag is not broken?
2) Also when manually shifted into 1st, 2nd, 3rd and D, I hear a moderate whining noise.
3) If the front pump tangs broke, would i still have reverse?
4) and if the governor driven gear was Fuc*ed, would it cause this? i seem to remember only 1st gear in this case?

thanks again to all..

Sounds like you blew up the rear planet. Have done several of these lately, a couple with aftermarket overseas rear planets, both 5 and 4 planet styles. They actually shatter the carrier.

If you pull the pan and find chunks of iron and steel, then that is proably what happened

If no manual 1st then your sprag is not what broke. Lumpdog is most likely correct. I agree to drop the pan. Either way the trans needs to come out and torn down and it will be easily found what went.

If you have reverse then it is not the pump. Your whining sound is not the pump you hear. If the pump was bad you would have no line pressure and it would slip in rev. or no rev. Not the beef sun shell either because you have rev., a broken sun shell would cause no 2nd, 4th and rev. gears. I have seen several rear planet ring gears crack causing the output shaft to spin inside the ring gear causing a sound like you are describing.

If you don't do trans work yourself, talk with the guy that built it and see if they will discount for "bad luck". It does not sound like a misbuild to me, just one of those things.

im having a close to same problem, but with mine, i can start my truck drive about 150 yards and than i have no go in forward or reverse at all, shut it down and do it again and i can go another 150 +/- yards, fluid is full and this is a pro built monster trans, i dropped 2200 on a year ago