Aftermarket overdrive

jraiten · Oct 12, 2014

I have a stock 1978 ford bronco that has a 4speed transmission.

The RPMs are too high on the highway. I would like to keep the original transmission and add an overdrive if possible to be able to travel highway speeds at a reasonable RPM.

Any suggestions?

miesk5 · Oct 12, 2014

yo jr,

WELCOME!

You have a NP435 4 speed, w/ NP205 T Case in there?

http://www.gearvendors.com/

Bully Bob · Oct 12, 2014

How high would those RPM's be at hwy speed.., say 65 mph..??

What engine..?

What size tires..?

Rons beast · Oct 12, 2014

Hery J

check out Gearvendors.com

jraiten · Oct 12, 2014

Thanks for the replies.

I think I have a T-18 tranny 4-speed with granny gear and I'm not sure what the transfer case is but it is stock and has a metal tag on the TC cover so I suppose I should be able to figure it out by the numbers.

As far as the RPMs I'm not quite sure since I have no tachometer but it feels like 4500 RPM or so. I don't feel like pushing it at those RPMs for too long.

I talked to gear vendors but they are not sure if their unit will work.

It is stock suspension, no lift, and stock tires which if I remember correctly are P235 R15.

Bully Bob · Oct 13, 2014

Then a temp. or permanent tach would be a first step.

Check me on this but 4500 rpm would be about 80-90 mph.

My guess would be.., you're not "hearing" that amount of rpm's.

miesk5 · Oct 13, 2014

yo jr,

Borg-Warner T-18 see pan diagram & much more @ http://www.novak-adapt.com/knowledge/t18_t19.htm

NP435 http://www.fordification.com/tech/transID-man.htm

more commonly New Process 205 gear driven transfer case.

&, less common New Process 203 chain driven transfer case

http://www.fordification.com/tech/transfercase.htm

Aftermarket overdrive

jraiten

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miesk5

96 Bronco 5.0

Bully Bob

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Rons beast

Active member

jraiten

New member

Bully Bob

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miesk5

96 Bronco 5.0

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