Overdrive Question - 4th gear

[Cuse99]

I have a 200 4R trans in my 84 El Camino and I'm looking to change the rear. Based on the following specs, I found a calculator that says I'll be at 2500 rpm at about 75pmh. For Highway I think that's reasonable.
Specs. - 4th gear: .67:1, 25.5 outside tire diameter, 3.73 rear. My 84 El Camino does not have a computer (its gone now) so I believe I the trans switches on pressure.

So here is my question. When does my car hit the 4th gear? Will it hit 4th at 65mph or will I only be in 4th at 75mph? Maybe at 60? How can I calculate this?

Thanks in advance.

 

[86LK]

2004r mph shift points

www.elcaminocentral.com

200-4r Wide open throttle

So I finally got my car running good and have some confidence in it. On my way to work today I finally put the go pedal to the floor for the first time with the new transmission. It didn't take long to bury the needle. My question is even tho I was at WOT the trans shifted gears at 4k rpms. The...

gbodyforum.com

post #2 "The governor controls the rpm the trans shifts at when in auto. You can have the wights shaved to adjust what rpm you want to shift at wot."

 

[Ernest]

I run a 700R4, similar to your 2004R and 4th(.70/OD) for me hits exactly @ 45mph, thats just easy on the throttle access road driving, and with 3.73 gearing, i run 2400rpm @ 70mph with 27" tall tires.

 

[rfpowerdude]

Shifting to 4th is controlled by the guv'nah. It will be at a relatively low speed like 40-45mph at light throttle. So, it will shift to 4th normally. However, do you have the lockup functional with something to control it? Even if it's just a manual switch?

 

[85Vette]

Shifting to 4th is controlled by the guv'nah. It will be at a relatively low speed like 40-45mph at light throttle. So, it will shift to 4th normally. However, do you have the lockup functional with something to control it? Even if it's just a manual switch?

 

[spidereyes455]

 

[olds307 and 403]

That is a great chart, quite a variance. A shift kit a little bit or governor mods can change it a lot.