will it hurt a stock 700r4 to shift manually? 88 gta 350 tpi.... thanks in advance...

NO

I click my shifter down and up all the time (within reason) to utilze the engine for compression braking and/or quicker acceleration.

~shrug~

that is what i was thinking... i mostley wanted to use it when accelerating through corners so i would not shift and break the tries free. hate spining out.

Hey guys, I have a highly modified 700R4 and unless if the guy I took it to isn't putting it together with quality in mind, I have broken 2 sprag assemblies within 8000 miles. First one he fixed on warranty, the 2nd one is on me. He said its because I drive downshifting through the gears. He says "Its from goin 70mph off the freeway down to drive then jamming it into 2nd, that'll do it." I don't do THAT but I go through town at 30mph downshift to D2 to let the exhaust rumble. Or coming to a stop light through town and engine braking, thats the extent of it. It may also be due to extremely high line pressure, I ride around with my drag radials on and it does not chirp in 2nd gear to relieve any stress on my trans. Car is in shop now getting 4.10's & sprag replaced and I can't wait to get it back to see how it runs from here on. I don't want another cost of a new sprag, so I won't be downshifting anymore. IMO

dont think i will be manually shifting then...

I downshift 3-2 @ 60 MPH all the time, traffic will be flowing very well, then suddenly slow to a stop. I especially do this when towing. Lets see if 5,500 lbs+ another 3,000+ won't hurt a 700r4 from repeated downshifts at speed (working on 50K on this one and over 80K on the same guts), I don't see how it could hurt one in a 3,800 lbs car.

25th- I have to wonder if your transmission guy is putting in the quality version of the upgraded sprag or a piece of junk/weak aftermarket groccery getter replacement. My 1983 transmission was supposed to have the weakest sprag made in a 700r4 and it still made it over 200K with no problems, towing, downshifting, etc.

Upshifting should not be a problem. Downshifting could be an issue especially 2-1 downshift. Couple that with 3.73 or higher rear ratio & down shifts can give a pretty good shock to the drive train. 4-3 downshifts aren't too bad & should bo okay.

Yeah, I think the bottom line is don't be a dipstick when you attempt to shift an automatic manually. USe common sense and keep the RPM's in a range where the drivetrain won't be too affected when you do it.

I'm sure there are other who believe that an auto is meant to be left alone when you are moving after all, that's the point isn't it?

I was told by my trans builder that having the gear selector set in any position but OD reduces line pressure and that when you down shift manually it does put a load on the sprag that it was not designed to withstand. He told me that he sees a lot of transmissions torn up this way.

I've heard that increasing boost valve size may help reduce slipage and therefore wear due to the higher line pressure they provide. But, I've also heard that higher line pressure during a downshift is just going to make the impact on the sprag and the potential for damage even greater. I'm not really sure what to believe.

I still down shift manually but I blip the throttle slightly to build some extra line pressure right before shifting down to the next lowest gear. I also try not to do it at high RPMs.

Later

Wrong. Line pressure is increased in 1,2 selector positions. Yes, the sprag will take the hit on down shifts, higher line pressure makes it worse.

" I still down shift manually but I blip the throttle slightly to build some extra line pressure right before shifting down to the next lowest gear. This is the best way of downshifting, as it is much easier on the gear train, it is similar to "double clutching" a manual transmission.

I have been very recently downshifting my car, but to be honest I do it at such a comfortable level to me I try to put as less stress on the tranny as possible...it is alot of fun doing this because even on the LO3 it feels like a totally different car when you're hauling *** in second or third gear...

I do the transition from OD to D at around 35-40mph, and I do the transition from 2nd gear to 1st at around 15-20mph

Just got my manual shifting (manual valve body) 700r4 out of the tranny shop cause the engine braking went away. It was the front sprag, but there are heavier duty sprags that can be used with double cage--longer life. We pretty much upgrades everything this time, cause I went to a different builder than in the past because of the performance reputation he has--He KNOWS what he is doing. I look at it as part of driving a performance car in a performance manner.

I never shift into 1st unless at a dead stop.