I am wanting to get a little more pep out of the 300 6Cyl that is in my 78 F150 4x4 flareside. I don't know if it is the performance of the engine itself that I'm having trouble with or if it is the gearing of the tranny and rear-end.

I don't know which tranny it has in it, but I can tell you this. It has the granny gear. I take off in second gear, shift into third at about 18-20mph, and if I really rev the rpm's I'll shift into 4th at about 35mph.

I'd like to get a little better performance out of the truck. Also it has absolutely no get up and go once you are in 4th gear. At 40-60 mph if you give it the gas like you are trying to pass or something it will slowly increase in speed. It's just not a peppy driver.

Is there any thing I can do about this??? I don't know if it is a transmission thing, the gearing in the rear end, or if it is a combination of a lot of things.

I've had the truck for a while, but have just recently decided to make it a lot nicer looker and driver. If I need to give info as to which transmission it has and which rear-end, I'll need some guidance as to how I find those things out. I'm sure there are numbers that tell me somewhere, but you'll have to guide me to where they are.

Thanks for the help.

Chad

 

That thing is going into fourth gear way too soon. YOu should be able to run third gear out to 50 or 60 mph. Sounds as though the thing is running with the transfer case in the low range. Either that or you have about a 5.00 rear end.

 

>Sounds as though the thing is running with the transfer case
>in the low range. Either that or you have about a 5.00 rear
>end.

How do I find out what the gearing in the rear end is?

Below are the numbers from that tag. Can someone decipher this for me?

H82 - top left
7HB - top right
509 - bottom left
390B - bottom right

I've designated where the numbers were on the tag incase that makes a difference. Also they were pretty hard to read, so an "8" may really be a "B" and vica versa. Thanks for the help.

Chad

 

There it is...5.09 (lower left)

 

[updated:LAST EDITED ON 16-Nov-01 AT 03:34 PM (EST)]Naw, H82 is the rear end code...its a 3.50 or so. I have the same rear in my Bronco. To be sure get the axle code off the tag in the door jamb. Once you have that compare it with the tag to make sure its still the original rear. Next go to this link and match your code to the ratio:
http://www.off-road.com/ford/bigbroncos/tech/ratio.html

Someone could still have switched ratios, but from what your describing they would have had 35" super mudders or something. I agree it sounds like the transfer case is locked in 4 low.

Ron

 

>I agree it sounds like the transfer case is
>locked in 4 low.

I'll check it out, but I don't know. When I put it in 4 low it gets even lower geared. It's not like there is no change from 4 low to 2 hi.

I've had this truck for over 10 years and it has always driven like this. I've probably put 60-70,000 miles on it. I can't imagin the tranfer case being locked in 4 low that entire time.

If memory serves me correctly Dad and I actually had to swap out transfer cases at one point.

Thanks for the info and the links. I'll check into it.

Chad

 

That kind of rules out "4 low", if you shift down and it goes down it can't possibly be stuck down there. On the other side, my Bronco has an SROD in it, 30-35 BEFORE 3rd gear! No fun in the off-road arena but it kicks ##### on the highway If you want to trade let me know!

Ron

 

>There it is...5.09 (lower left)


Agree with Tetraruby. There is no "H82" code in the Bronco page. H8 is a 3.08.

BUT!!!! If he's winding out in 3rd prior to 35mph he's got a numerically higher gear ratio in the diffs.

Put that thing on jack stands and turn the drive shaft (make a mark on the shaft, and both tires) and count driveshaft revs for 1 tire rev.

This will give you your ratio. I have a 3.55 and I max out in 3rd at 48 mph at 4,000. If your going about 35mph in 3rd then you've got somewhere near 4.80-5.10 range. These ratios aren't standard.

 

Thanks,

I double checked yesterday. I put it in 4 low. Amazingly slower:-) Still took off in second gear had to shift before 10mph (probably could have taken off in 3rd). Shifted from 3rd to 4th at about 15mph. Couldn't drive over 20-23mph in 4th gear with the transfer case in 4 low.

This really sucks when I want it to be a daily driver. However in the past when I've taken it 4 wheeling this truck will go anywhere. Just let it crawl along and it will climb over anything.

Thanks,

Chad