recaro xfire

i always drive my 700 r4 in OD is that gonna ever hurt it? i never drive it in just drive
even tho the owners manual says so!thanxs for any info !

transfixleo

If built properly it shouldn't really matter. I like using D if I have higher mileage and am unsure of the Input Sprags condition, as in D there is the Overrun clutches to help out but not in OD.

Z28DJP1987

No, it will not hurt your 700r4 because you are already in 3rd gear until you go over a certain speed such as 40mph.

82suped-up-coupe

I don't know myself
but when I was having one built for me awhile ago(sold it before I got around to putting it in the car)the builder told me it would kill the od clutches if it was strugling to much like on hills and such
if it is stock in the car you'll have a sensor or somthin' that'll disengage the od if need be

so what he says is if it is stock it's ok to stay in od all the time, but if it's a mod check that you have that sensor thing

Rich


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www.angelfire.com/ri/camarogarage

recaro xfire

transfix that just all went over my head!
in stupid man terms what is the difference between drive and overdrive? if in the city will drive give me better fuel economy?

transfixleo

Sorry, it was 4:11 AM here and already 81F and muggy! Let me try again.

In city driving you probably will not ever get INTO O/D so it won't matter. Now onto the Overrun Clutches I mentioned.
When you drive in the D, 2 or 1 positions you will notice that when you let off the gas that there is a certain amount of deceleration or engine braking as it is called, more at higher speeds and lower gear ranges. Now if you do the same in the O/D position you will not feel that and will more or less coast. What happens is, along with the limit on what upper gears you can get into, there is a clutch pack that is applied and it keeps the Input Sprag (ratchet type device that transmits power inside the tranny, it overruns on coast and in 4th) from overrunning. This pack is called the Overrun Clutches for obvious reasons.

Now the sprag tends to wear out in time due to its inherent design weaknesses so with the sprag not applying and reapplying it wears it less than it otherwise would. For this reason (you don't know what condition it is in now) it is probably wise to keep it in the D position AND to manually downshift from O/D when accelerating (that is where the highest wear comes from) so as to maximise it's life.

For anyone with a 4L60E this does NOT apply to you as the trannies, while essentially the same, the O/R Clutches do NOT come on in the D position but instead are only on in the 2 and 1 posotions but s a consolation they come with the most durable Sprag design (as of @ 1996 up) that the 700 family ever had.

Does that help or should I jump in the pool (it is in the upper 90's now)and try again?

recaro xfire

that was good information thank u! now i got a better understanding on trannys! also whats this thing called a vette servo, what the heck does it do? why are people putting them into their 700 r4's? how much does it cost to get done? thanxs for everything! recaro xfire

Mark A Shields

The corvette servo replaces your old servo, it has a larger apply area that firms up shifts. There is a website http://www.hptransparts.com/,
I believe you can get it for $10.

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'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER, NO CAT
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat
2:73 GEARS
Rebuilt 700R4, with manual valve body
B&M Megashifter, 5" Autometer Tach w/shift lite
Soon to be installed
3:73 Richmond Gears and 3" Hooker Aero Chamber
Corvette Servo & .500 boost valve
15.61@ 95.2mph G-Teched, 1-2 shift slippage, and just replaced a burnt plug wire
"There is nothing more addicting than speed"