Tooky
Serious about performance
(This is mostly a rehash from my Vortec head/cam swap thread in Member's Projects, but at 13 pages the info is getting hard to find. And I wanted to let everyone know of the anchor pin failures/upgrades.)
When I first got my built 700R4 back in 2005, while experimenting with stiffer 1-2 accumulator springs, I suddenly lost 2nd and 4th gear. It turned out to be that the trans was shifting so hard internally that the 2-4 band anchor pin sheared the head off. I didn't realize this because the high stall torque converter *combined* with the governor causing too low of part throttle shifts, resulted in "soft shifts" (even though the tranny was apparently shifting very hard, internally).
I R&R'ed the tranny and pulled the pump and input drum etc. and repaired the anchor pin back then, along with a new band, and it worked fine since.
Until just 2 weeks ago, I just got my new Vortec heads/cam installed and was driving it for about 2-3 weeks and suddenly lost 2nd and 4th gear again. :roll:
Transmission Repairs
I got a new 300M billet anchor pin and I had an opportunity to borrow the use of a lift the same night, so I opened up the transmission and dropped the valve body and it was just as I suspected!! Another sheared 2-4 band anchor pin!
New 300M Billet anchor pin $9 from www.bowtieoverdrives.com, next to my FIRST (2005) broken stock anchor pin:
The 2nd broken anchor pin, the one that just broke last week:
My advice to ANYONE racing their 700R4 is to put the damn billet anchor pin in when you have the chance!! $9 in the beginning would have saved me 1 tranny R&R, and 1 valve body drop to replace the 2 that I broke. :doh:
By popping off the outer 2-4 Servo cover snap ring (to loosen tension on the band), and carefully maneuvering the band from the driver's side, I was able to fix it without having to R&R the trans this time! It took me about 4.5 hours to do. I found a chunk of the band about 0.5"x1.5" laying in the pan, I think it chipped off after the pin broke and jammed the band against the case.
Back on the road
Fortunately, after putting it back together, it hits 2nd and 4th as hard as ever at part throttle. At WOT it seems about the same as before but I'm starting to get nervous about whether this tranny can handle the torque the motor's putting out now... :roll:
When I first got my built 700R4 back in 2005, while experimenting with stiffer 1-2 accumulator springs, I suddenly lost 2nd and 4th gear. It turned out to be that the trans was shifting so hard internally that the 2-4 band anchor pin sheared the head off. I didn't realize this because the high stall torque converter *combined* with the governor causing too low of part throttle shifts, resulted in "soft shifts" (even though the tranny was apparently shifting very hard, internally).
I R&R'ed the tranny and pulled the pump and input drum etc. and repaired the anchor pin back then, along with a new band, and it worked fine since.
Until just 2 weeks ago, I just got my new Vortec heads/cam installed and was driving it for about 2-3 weeks and suddenly lost 2nd and 4th gear again. :roll:
Transmission Repairs
I got a new 300M billet anchor pin and I had an opportunity to borrow the use of a lift the same night, so I opened up the transmission and dropped the valve body and it was just as I suspected!! Another sheared 2-4 band anchor pin!
New 300M Billet anchor pin $9 from www.bowtieoverdrives.com, next to my FIRST (2005) broken stock anchor pin:
The 2nd broken anchor pin, the one that just broke last week:
My advice to ANYONE racing their 700R4 is to put the damn billet anchor pin in when you have the chance!! $9 in the beginning would have saved me 1 tranny R&R, and 1 valve body drop to replace the 2 that I broke. :doh:
By popping off the outer 2-4 Servo cover snap ring (to loosen tension on the band), and carefully maneuvering the band from the driver's side, I was able to fix it without having to R&R the trans this time! It took me about 4.5 hours to do. I found a chunk of the band about 0.5"x1.5" laying in the pan, I think it chipped off after the pin broke and jammed the band against the case.
Back on the road
Fortunately, after putting it back together, it hits 2nd and 4th as hard as ever at part throttle. At WOT it seems about the same as before but I'm starting to get nervous about whether this tranny can handle the torque the motor's putting out now... :roll:
