Hello, my buddy(not me) shifts his car like a manual (th350). He even downshifts when slowing down. He runs around town with it in second gear... it feels and sounds awsome....but....this can't be good for the tranny could it??



.. i'm starting to get in the habit of leaving mine in second... and jumping on the gas................kinda fun...... i think i better stop..

rob

 

i only do it when i race or need the extra RPM's. the only thing it will hurt probly is your gas mileage. the 350's are good strong transmissions and should be able to take that abuse with no problems.(dont quote me on it though)

 

I've seen this come up ALOT...

You will NOT hurt the transmission ( unless it's already messing up, then you "might" make it "seem" worse ) shifting it manually. In fact, most GM automatics have MORE line pressure when manually shifting into / from a gear, this means stronger shifts, less slippage, better on the tranny.

IF you do it so it will wind up quicker, and you like the way it "jumps" more when you leave it in 2nd around town, the only thing it will hurt is your gas mileage


HTH
Chris
85 IROC

 

My TH-350 has to be manualy shifted. It has a full manual Trans-Go in it's belly.
It's not a daily driver though! Only race.

Ron

 

My dad manually shifts his tranny up and down for years. He's never had a problem. The only thing you should watch out for is down shifting it when your flying. Oh and your gas milage. But none of us got into this stuff without caring how much gas we gussled right?

 

How about on a 700r4. Are they strong enough to take it. I just had it rebuilt 100 miles ago or so. I used the b&m clutch kit, the full rebuild kit, not the shift kit. I like to downshift to slow down too.

Will I be alright or should I curb my habit. I am asking because the rebuild I just did was not cheap, I don't want to do it again.

 

As long as you're not doing neutral drops, shifting in Reverse at high speeds etc, it should be fine.

I usually leave my 700 in D around town, but alot of times I shift it through the gears when I feel like it.....when I know I'm getting on a road where I'm going to get up to at least 45 mph for a stretch or so, I put it in 4th ( OD )


HTH
Chris
85 IROC

 

so you guys just leave it in 2nd the whole time? Like when your at a stoplight or at a complete stop, your still in 2nd, then you just get on it from that gear?

 

Well 'JoshZ28' If I leave my racecar in second I will start off in second just like a stick.

With my Vette I throw it in drive, and focus on the tunes!

Ron

 

Reverse MANUAL valve body means simply this........

Think of the shifter in the floor......instead of: TURBO 350 ( 3 spd)

P
R
N
D
2
1

It's now like this

1
2
D
N
R
P


The main purpose was originally so you couldn't accidntally hit neutral when shifting to D at the track / racing.

"MANUAL" valvebody means exactly that...

If you put it in 1st, it will STAY in 1st as long as you leave it there, and if you leave it in D at a stoplight, it start from D, not 1st. It's a stick with no clutch.


If you put a normal type auto in 2nd gear at a stoplight and take off, pay attention to your car.....you SHOULD feel it take off in 1st, then shift to 2nd. It just won't shift out of 2nd until you move the shifter.


HTH
Chris

 

what speed does OD kick in at? i hate my OD its it touchy as hell, it kicksdown at the slightest touch of the pedal.

 

yeah i am always in overdrive unless, i feel like going threw the gears at a light. and usually if i race i shift at like 4500 rpm to 5 rpm.. if someone comes next to me and wants to race and where going 45 to 50 mph, i just down in drive to get into the torque and hp ranges...

the 700 r4's first gear is a beast!!!!

 

I am reviving this thread instead of creating a new one, in order to delve a little more into exactly what should and shouldn't be done to a 700r4.

About 9,000 miles ago I had my 700r4 rebuilt and restored with heavy duty clutch packs. Two days ago the 3/4 pack slipped on the highway and I have to bring the car in again as the 3/4 pack is toast... I frequently downshift to 3rd on the highway, to grab more passing power, and when I get there I throw it back up to OD to enter 4th. I also do this on the street when I expect a race.

Have either of these habits expedited the failure of the 3/4 clutch pack? I would like to know, I don't want to hurt my Iroc!

 

First, reverse pattern is P R N 1 2 3, instead of P R N 3 2 1, on the TH350 or TH400, which I do not like. Full manual TH350's or TH400's are fine just stick with the forward pattern.

Second, if you want the transmission to stay in overdrive instead of downshifting easily, you will need to change the TV plunger sleeve to one that has later 4-3 downshift passages, or modify yours to eliminate the 4-3 kickdown at higher speeds (75 mph & up).

Third, the 4-3 downshift brings off the 2-4 band, and is not responsible for the 3-4 clutch pack failure, as it is already on (applied).

Fourth, the builder has to do more than add the so-called HD 3-4 clutch pack to make the 700R4 live.

 

They did alot more, I was just clarifying that the clutch pack is heavy duty.

My transmission guy told me downshifting on the highway won't hurt the tranny... he also told me OD is for highway use only, and using OD on the street or at the track abuses lockup. I know we race our cars, and that accelerates wear and tear. But 9,000 miles?! The damn thing was brand new, I can't be driving it THAT hard! It sees the track once in a while, and I drive it fast on the street too. What caused this? Clutch packs should last at least 30,000 miles no?

 

my 700r4 shifts into OD at 30MPH, i normally do like 1000RPM @ 30MPH.....the only thing bad about manually downshifting is if your like my buddy who was downshifting to slow the car down because his brake pads were low....def not a good idea to use your tranny to slow the car down....extra shock not needed...stupid monte carlo owner :P

how so? or is that a secret? you should publish a nice long and instruction manual with color photos some day on how to rebuilt performance 700R4's....I'd buy it

 

Is there a GM tech on here that can verify this? Just wondering because I have never heard this. Not calling the guy a liar just like some backup if its true.

 

The car will shift into OD at a certain mph depending on the rear end gear. With a 2:73 it shifts around 42.

 

Maybe at part throttle but not at full throttle will it shift into OD........ Also you can leave it in OD all the time and it will not harm it. I know people who race and they leave them in OD.

 

oh what am I thinking. I've got my temps so I can't full throttle it yet.

 

Well - the guy who is currently working on my transmission races his cars, and he told me OD around town (stop & go) will accelerate the wear of a transmission. I never heard of this! Can anyone verify that this has merit?!

 

Thats crap. Just leave it in OD. Let the transmission do what it was designed to do, automatically shift for you.

 

Far be it for me to disagree with anyone (yea right), but with a factory style (or anything close) valve body you’re MUCH better off letting it shift for you. The factory valve body boosts the line pressure prior to shifting gears which will prevent some slippage/wear. If you shift manually the pressure pretty much stays down.

If it’s shifting at the wrong rpm change the governor setting/make sure the TV cable and valve are adjusted/working right.

 

In a recent issue of CHP they did a test on a 355ci 700r4 car. The test was centered on a B&M SuperCooler for the transmission.

I quote:

"On our first leg of the test, we drove the [car] in the drive position for approximately 20 miles through a winding canyon road at about 45mph... Next we wanted to see how the trans held up to freeway driving, so we shifted the 700r4 into overdrive and drove the [car] about 10 miles through the glendale area..."

This clears my inquiry up a little.

 

When having the lever in the "1" or "2" you activate the intermediate/reverse boost valve, which "raises" line pressure (unless by chance you have a small one from an earlier year pre 1988). This allows you to get firmer shafts when manually shifting form 1 to 2. If your shifts are "softer" than if you left in the "drive" position, you have a smaller than required intermediate/reverse boost valve. Minimum is a .282, I use the .296 for just this purpose (manual upshifting). In town, leaving it in the "drive" position will not hurt anything, but could help a little. Remember 1st & 2nd are underdrive, and 4th overdrive, with 3rd being "direct". The least amout of wear occurs in drive/3rd.

 

Yes! Thank you ProBuilt with the info! Finally, the 'just leave it in OD' assumption has been dispelled.

Now beyond that, when one wants to go from D to OD for the highway how should one do it? Should the transmission be upshifted whilst on the acceleration ramp (fun!), or should OD be engaged before it is needed (before you get to the freeway)?

 

That doesn't "dispell" anything. All he said was that the transmission will see less wear in 3rd gear, or 1:1. I personally don't see leaving it in D doing anything except wasting gas.

 

Well - forgive me for taking the advice of a professional transmission builder over your personal opinion...

Gas Mileage vs. Transmission wear?

Thats an easy decision for me!

 

You misunderstood him and me. He didnt say leaving it in D will cause less wear, he said the least amount of wear will occur in 1:1, or 3rd gear. When driving if left in d you will encounter 1st, 2nd, and 3rd gear in the city. The OD on our cars was put there for a reason, to save gas. If you are so concerned with wear and you believe that OD causes excessive amounts of it then just ditch the 700r4 and go with a th350.

 

Well, it OD has wear, what about 1st and 2nd gear?

 

Exactly my point. It's a trade off. Nothing is perfect so keeping it in D wont do much except for waste your gas. 1st and second, as probuilt stated, are underdrive gears. If you think OD will put excessive wear on your transmission then 1 and 2 will do the same thing. GM designed the 700r4 as an OD transmission, therfor leaving it in OD will cause no damage and save you gas. If gas isn't at all a concern then the 700r4 is not for you. Get a th350 or 400 and throw the 700 down a hill because the OD in it, which is the sole reason for even having a 700 r4, aparently causes excessive wear. I like the fact that I can cruise down the highway at 70 mph with some nice gears out back and still get descent gas mileage, but hey, thats just me.

 

Well - so far about 5 or 6 outside the board have confirmed that OD around town would cause more wear than D. If what you say is correct, than you are effectively negating Pro Built's statement on the matter. Man, I am worn on the subject already...

All this aside, if OD does indeed cause more wear in town, it can't possibly be the cause of this unbelievably early clutchpack failure. I am starting more and more to think the guy that built the tranny did something wrong... therefore he is trying to cop out by implying my driving habits are to blame.

 

My statement was "direct" (3rd) causes the least amout of wear. When in town (45 mph & under), leave it in "drive". Above that then "overdrive" has an advantage, below that speed, especially if you accelerate and deaccelaerate constantly, then when left in overdrive, it can create excess wear by going in & out of overdrive, back to third and back to overdrive, back to third, etc. It will cause the 2-4 band to wear faster, and possibly burn the band up.

 

Thank you for clarifying that. I thought thats what you meant.

 

When you guys downshift your auto's, u keep some throttle right? if i downshift mine and totally get off the throttle it feels like the tranny is taking more abuse then if i apply some light throttle and downshift that way at the correct speed. when adding light throttle it just downshifts very smoothly and without jerking. also, doesnt leaving it in 2nd gear, while being tons of fun, cause the tranny temps to get hot fast? how many miles can u go in 2nd gear at high speeds (50ish?) without heating up the tranny too much?

 

When I downshift mine I use no throttle. Seems to work great for me.

 

When downshifting, do it like you were double clutching a stick. Give it throttle at the same time you are making the gear change, then you can let off of the throttle once the rpm's of the gear & engine match (about a half a second). If you do not give it throttle when making a gear change (downshift), you can wear out the band or clutches much faster.

 

This is good stuff. Thank you Pro Built for all the clarification!

My transmission shop wanted to blame it all on racing at the strip, but I think after this topic I realize I have been practicing one or two things that helped the early clutch pack failure. Namely OD in stop and go traffic, and not throttling to assist the downshift.

 

When downshifting, do it like you were double clutching a stick. Give it throttle at the same time you are making the gear change, then you can let off of the throttle once the rpm's of the gear & engine match (about a half a second). If you do not give it throttle when making a gear change (downshift), you can wear out the band or clutches much faster.

 

Not to step on your toes but where did you come up with this idea of having to give it throttle? Never heard that one before?

 

from what i've heard the reason the 700R4 eats the 3-4 clutches is because the 3rd clutch pack isnt releasing fast enough when 4 engauges. if its not done with in a fraction of a sec it constantly wears the clutches. if you've ever noticed the 700R4 is the only tranny i ve seen that has a 3-4 reprogram kit that you can buy. if it doesnt get reprogramed adding a shift kit just aggervates the problem. the more exspensive kits sometimes offer the reprogram kit with the shift kit. it all sounds good to me and makes perfect sense, but again this is just what i've heard and read.
also down shifting a 350th wears out the band and direct drum bushing. leaving it in 2nd doesnt bother as much. it just when you drop it from 3 to 2 when the band gets applied it usually ***** the drum a little every time and causes premature bushing failure, besides the sprag this is the other biggest failure on a 350.

 

A 350 as in cubic inches? Or a TH350 transmission?

 

TH350 tranny. notice my lisp after 350.......th:lala:

 

lol. I think my next transmission will probably be a built TH350 or TH400... the 700R4 is just junk

 

if you use a 700R4 you need an 87 and later and a reprogram kit for the 3-4 shift. and an extra tranny cooler. then they'll last like a 350 ttthhhhhh.

 

Well...

My 700R4 is equipped with heavy duty clutch packs, a case saver, a better vane assembly (i think), and a shift kit. I am not sure if it has the 3/4 reprogram - I'll have to ask the guy who built it (hes a dick...)

When my clutch packs went - thats all that went. Thankfully, the rest of the tranny is still fine. If it eats the packs again within 10k miles, I'll assume it needs the reprogram. Trying to get info out of the shop that built it is like trying to squeeze water from a stone! They treat me like I'm some stupid kid who knows zip about cars, and it pisses me off big time...

I plan to pick up a secondary trans cooler soon (the summer in vegas is hellish)... so hopefully the 700R4 will last until my big plans start to unwind.

 

Does this kit come with the 3-4 reprogramming kit?

http://www.pro-built.net/index.cfm?f...t&productid=82

 

Ok, I have asked this very question to many a mechanic, and also some racers that I know. They have ALL told me that its OK to leave it in OD through town as well, but the lockup will cause things to wear a little bit quicker. So drive in town, overdrive on freeways, highways, etc.....my tranny locks up at about 38 MPh or so, so I like to leave it in drive for a while. rides better as well. I have had some issues with the tranny (rebuilt, new stronger clutch packs, corvette servo, shift kit) and I thought it slipped once, but I tihnk thats just the gear I was in and the fact that my engine has some issues sometimes.

 

I bought and installed the B&M 3-4 downshift valve for mine years ago. It was a simple part to change and well worth it! Before I changed it, my trans used to jump back and forth between third and fourth gear constantly. It seemed like it did that the worst when the trans was cold. That's the only part I've ever changed on mine, plus I change the fluid and filter about every 50,000mi., and my 700r4 still shifts nice and firm with over 190.000 miles on it

 

Myself i love the 700rm i have an 86 iroc with 136k and an 83 silverado all with 700r's. And i run them in the ground. And in the prosses of replacing the th350 in my 86s10 blazer with the 700. Great on gas and a mean take off. Would'nt take anything for it. Just make sure you keep it cool and clean. Keep one thing in mind if the 700 was that bad of a trans do you think chevy would have run it in the vette for so long