700r4 Help
Thread Starter
Intermediate
Joined: Aug 2006
Posts: 40
Likes: 0
From: Maui Hawaii
700r4 Help
Background, I have a level 2 700r4 Raptor trans. I've run it without issues for about three years. My car is a dedicated drag car, high 12's, low 13's, so not a beast by any means. I race about 15 times a year, 3.54:1 rear end gears. '84 car, the trans is from an '86.
I only manually shift the car. When I launched, after doing my burn out, the car did not move forward, well maybe a few feet. I was able to reverse out and limp back to the pits. When I went from 2nd to park there was a grinding noise. I again was able to limp home, 2nd and 3rd seemed fine, but I just baby'd it. Same noise getting it into park from third at home.
I am rebuilding it myself. I just now taking it apart, and just my luck, nothing seems to be broken so far. A tech guy at Monster transmission gave me a guess of forward sprag failed. Raptor won't respond to me. Fluid is clean and smells fine. There is, what I consider to be, a normal amount of black in the pan and valve body. Clutches I've removed all look fine.
So my first question, any guesses on what failed?
Mahalo,
Thomas C.
I only manually shift the car. When I launched, after doing my burn out, the car did not move forward, well maybe a few feet. I was able to reverse out and limp back to the pits. When I went from 2nd to park there was a grinding noise. I again was able to limp home, 2nd and 3rd seemed fine, but I just baby'd it. Same noise getting it into park from third at home.
I am rebuilding it myself. I just now taking it apart, and just my luck, nothing seems to be broken so far. A tech guy at Monster transmission gave me a guess of forward sprag failed. Raptor won't respond to me. Fluid is clean and smells fine. There is, what I consider to be, a normal amount of black in the pan and valve body. Clutches I've removed all look fine.
So my first question, any guesses on what failed?
Mahalo,
Thomas C.
Last edited by mauitom; Nov 27, 2013 at 01:58 AM.
Racer
Joined: Oct 2012
Posts: 350
Likes: 2
From: Huntsville AL
The sprag, or overrunning clutch is a good ffirst guess. If you are going to rebuild yourself, go ahead and order an ATSG rebuild manual (under $30 on line, eBay or Amazon). The manuals have more current info than an FSM and cover a range of years. The manual also has a chart the describes the torque path through the transmission for each gear selected. That chart, along with your synptoms will help focus your search for damage. You will need the info in the manual to properly reassemble the trans and set end clearances. The clearances can be off by quite a bit if you have to replace any hard parts.
Thread Starter
Intermediate
Joined: Aug 2006
Posts: 40
Likes: 0
From: Maui Hawaii
Sorry, I should have mentioned I have rebuilt one before, so I have all the manuals, tools, etc.
In reviewing the chart on what is applied in each gear, it looks like the two areas that are used in low and not 2nd, the low roller clutch and low reverse clutch appear to be my best guess.
So far, I have the guts out and can't find anything broken. The breakdown was so sudden and clunky, I expected obvious broken parts in the case, which so far is not the case.
I'm reviewing how these two areas are applied in the valve body, perhaps I had a hydraulic failure in the valve body? That's my next area to examine.
Thank you for the replies, as always, I was hoping someone on the forum would say, hey! That happened to me! :-)
In reviewing the chart on what is applied in each gear, it looks like the two areas that are used in low and not 2nd, the low roller clutch and low reverse clutch appear to be my best guess.
So far, I have the guts out and can't find anything broken. The breakdown was so sudden and clunky, I expected obvious broken parts in the case, which so far is not the case.
I'm reviewing how these two areas are applied in the valve body, perhaps I had a hydraulic failure in the valve body? That's my next area to examine.
Thank you for the replies, as always, I was hoping someone on the forum would say, hey! That happened to me! :-)
Intl Council of Corvettes
Joined: Aug 2011
Posts: 139
Likes: 3
From: Huntsville Alabama
Don't know anything about Monster transmission but I would think Performance Torque Converters can help ya. They are pretty helpful people and they know the 700-R4s really good. I was just over there this mornning as I had them check my TC because we thouht is was leaking. Turns out it somehow developed a hair line crack of some sort in the pumphousing. My symtoms were not like yours it was just a constant drip when the engine got hot and was losing pressure.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
Don't know anything about Monster transmission but I would think Performance Torque Converters can help ya. They are pretty helpful people and they know the 700-R4s really good. I was just over there this mornning as I had them check my TC because we thouht is was leaking. Turns out it somehow developed a hair line crack of some sort in the pumphousing. My symtoms were not like yours it was just a constant drip when the engine got hot and was losing pressure.
