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Help from the herd on upgrade options

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kristopherdb

Help from the herd on upgrade options

So my 85 4x4 flareside with the l6 and manual 4 with granny gear is very much still a work horse and wants to climb mountains and pull things. However my goal is a cruiser that can keep up with today's traffic on our freeways here in Portland, OR.

I have to work on the transfer case because it keeps falling into 4H so before I go tearing out transfer cases and spending a few hundred more on a rebuild kit for it is there a path or article I should follow to get me from farm to fantastic?

I would guess the tranny needs replaced with an overdrive one? Not sure how I figure out what would fit or not, I am in Portland so on CL or the marketplace I see the picking is good and I can get a whole setup or pick pieces but have no idea even were to start. I wouldn't mind an automatic. Right now when I hit a rock on the road it feels like I am jumping the grand canyon. Granted I drive a 7,000 recent tundra and only have it to compare too. It sounds like its doing 200 MPH when its doing 55 etc...

I just need some direction and you guys have always been very helpful pointing me in the right direction.

1985 4x4 F150 Flareside 6L Manual 4 with Granny gear

Gary Lewis

Re: Help from the herd on upgrade options

Administrator

One popular upgrade on these trucks is to go to a tranny with an OD, as you mentioned. That drops the RPM and the noise, and makes a world of difference. But, these trucks were made when overdrive transmissions were just coming in, so the pickings from this era of trucks is slim, and not too good. In fact, none of the OD transmissions from this era none were really strong enough to tow very much in stock form.

But not long afterwards Ford came out with the ZF5 manual and it is stout, a serious truck transmission. I discuss the one that was intended for Dad's truck here: http://www.garysgaragemahal.com/transmission.html. But, since you have the small-block bolt pattern on the 300 six you won't have any problems mating a ZF5 to your engine. And the transfer case will bolt right to the back of it - but you have to find a 4wd version.

If you want to go with an auto you have two choices - the AOD or the E4OD. The AOD was originally not very strong, but can be built with aftermarket parts into something that has plenty of strength. And the E4OD had some early problems but later versions from the factory were quite strong. However, it takes an outboard computer/controller and you are looking at $800 in addition to the price of the tranny.

I'd recommend the ZF5. First gear is a granny gear and you can move mountains w/o going into 4lo. And the 5th gear is a good OD ratio that will drop your noise and RPM down dramatically. But, what rear gears do you have now?

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

kristopherdb

Re: Help from the herd on upgrade options

How do I know which gears I have in the rear?

1985 4x4 F150 Flareside 6L Manual 4 with Granny gear

Gary Lewis

Re: Help from the herd on upgrade options

Administrator

If you have the certification label on the driver's door post you can decode it on the page in the menu of Specifications/Certification Label. At the bottom right of the one on that page you'll see "38", and if you click on that it'll take you to the page in the menu of Specifications/Axle Ratios where you can decode the axle number from your certification label and/or decode the tag that may be on the axles.

The reason you want to know that is the OD ratio of the ZF is .76:1. And the AOD's OD ratio is .67:1. So, if you have the ubiquitous 3.50 or 3.55 axles then the ZF5 would give you the equivalent of 2.66:1. That worked well on Dad's truck with a warmed-up 351M, dropping the RPM at 65 MPH to about 1800, and it pulled any hill we saw at 65 MPH on the highway on cruise. And that should work well on a 300 six as that's close to its peak torque.

But, if you have 3.0 axles, which are uncommon - especially in 4wd trucks - your effective ratio would be 2.28 with the ZF and 2.01 with an AOD. That's too high and very few engines would like that.

Gary, AKA "Gary fellow": Profile

kristopherdb

Re: Help from the herd on upgrade options

As far as I can tell my code is 18

1985 4x4 F150 Flareside 6L Manual 4 with Granny gear

Gary Lewis

Re: Help from the herd on upgrade options

Administrator

I don't see a signature that tells me anything about your truck, but an 18 had either 3.00 or 3.08 gears. I would put both rear wheels on jack stands so neither touches and turn the driveshaft 10.0 turns, counting the rear wheel rotations. That will tell you for sure, but the ratio has probably not been changed.

But, assuming the 3.0 is correct, with the ZF's .76 OD you'd only be turning about 1600 RPM at 65 MPH. Let's see what David/1986F150six says his RPM is at 65 MPH. Perhaps the six will pull that.

Gary, AKA "Gary fellow": Profile

kristopherdb

Re: Help from the herd on upgrade options

Thanks its kind of hard to read as its very faded. trans says "A" and Axle says "18" or "1B"

1985 4x4 F150 Flareside 6L Manual 4 with Granny gear

1986F150Six

Re: Help from the herd on upgrade options

Administrator

Thanks for the invitation to the party, Gary!

But, if you have 3.0 axles, which are uncommon - especially in 4wd trucks - your effective ratio would be 2.28 with the ZF and 2.01 with an AOD. That's too high and very few engines would like that.

I am not sure I totally agree with that as my son's 1984 with 4.9L, 4 speed manual O.D. and 2.47 rear gears did fine on the interstate, until a hill came into sight! The 2.47 gears with .71 [?] O.D. = 1.75. With this arrangement, it could return 26 mpg @ 65 mph. This was before gasohol.

Regarding towing, it would not! It ran almost 40 mph in 1st gear and regarding acceleration, it was a dog. It idled @ ~8 mph.

With my 1986 F150 with 4.9L, 4 speed manual O.D. and 3.08 rear gears, @ 65 mph, the engine is turning ~1800 RPMs.

I believe the "ideal" axle ratio for a stock 300/4.9L and my driving style would be the 3.25 option.

Gary Lewis

Re: Help from the herd on upgrade options

Administrator

David - Thanks! I knew that you'd have better info than I do.

Ok, you said the ideal rear axle ratio with your .71:1 OD would be 3.25, so you are saying the ideal effective ratio would be .71 x 3.25 = 2.31:1. So, the ZF5's .76 OD ratio x 3.08 axle ratio = 2.34:1 and that, too, would be essentially ideal - for your driving style?

Gary, AKA "Gary fellow": Profile

1986F150Six

Re: Help from the herd on upgrade options

Administrator

Yes, I agree.

Ford F834

Re: Help from the herd on upgrade options

Administrator

In reply to this post by kristopherdb

According to this post on FTE, axle code 18 on a 83-86 truck is an open differential 8.8 inch axle with 3.08's.

My 4x4 swap that I just did has 3.00 gears, and I am thinking of adding overdrive. When it was a 2wd truck it had 2.75's which I liked except for 2nd gear starts were a little harsh, so I used a close ratio T19 that came out of my diesel. I have not driven it yet with the 3.00's but I am guessing I will still be reaching for another gear for that straight six.

SHORT BED 4-DOOR DIESEL: 1986 F350 4x4 under construction-- 7.3 IDIT ZF5+GVOD

STRAIGHT SIX 4X4: 1981 F150 2wd to 4x4-- 300 I6 close ratio diesel T19, hydroboost brakes, Saginaw steering

BIG F: 1995 F-Superduty under construction— converting to 6.9L IDI diesel ZF5+DNE2

kristopherdb

Re: Help from the herd on upgrade options

So keeping my eye out for a ZF5 off a 4 wheel drive vehicle is my goal? Do I keep the same transfer case and should go ahead and repair the one I have?

1985 4x4 F150 Flareside 6L Manual 4 with Granny gear

Gary Lewis

Re: Help from the herd on upgrade options

Administrator

Jonathan - You don't believe the Axle Ratios page? The one with info from Ford's Master Parts Catalog? You'd rather put your faith in some random post on the "other" forum?

(Where's the ROTFL emoticon?)

Kristopher - Yes, go find a 4wd ZF5 for the small-block bolt pattern, meaning from a 300 six, 302, or 351W. And any of the transfer cases will work as the transfer case bolt pattern is one of the few things Ford kept standard. So you can repair the one you have and it'll work with the new tranny.

Also, you'll need to get the shift lever for the ZF as well as the floor cover as the ZF is much taller and won't fit under the cover you have. But the floor pans stayed the same until the mid 90's so one off of a later truck will work.

And, the ZF is rugged but many of the older ones are well and truly worn. So you may have to have one rebuilt and that takes special tools and has a price tag to it. I paid $500 for mine several years ago and put another $1000 in parts and labor in it.

Gary, AKA "Gary fellow": Profile

Ford F834

Re: Help from the herd on upgrade options

Administrator

Gary Lewis wrote

Jonathan - You don't believe the Axle Ratios page? The one with info from Ford's Master Parts Catalog? You'd rather put your faith in some random post on the "other" forum? (Where's the ROTFL emoticon?)

Gary Lewis

Re: Help from the herd on upgrade options

Administrator

Gary, AKA "Gary fellow": Profile

kristopherdb

Re: Help from the herd on upgrade options

I found a pair of zf5's one has cracked tail, and the other a twisted output with transfer case for $500, is this worth it.

1985 4x4 F150 Flareside 6L Manual 4 with Granny gear

Gary Lewis

Re: Help from the herd on upgrade options

Administrator

You'd have to have someone meld the two into one, and while in there you will need them to replace any worn or broken parts. That can be a long process as they have to disassemble, check things out, and then order replacement parts.

So if you have someone that works on ZF's lined up, then maybe that would work. But those people aren't plentiful from what I've found. I would rather pay more for one that is said to be good.

Or, buy one that is known to need rebuilding and use it as a core on a rebuilt with a warranty. I've bought parts from Midwest Transmissions and they seem to be pretty good. But they also sell rebuilt transmissions, so you might talk to them.

Gary, AKA "Gary fellow": Profile

kristopherdb

Re: Help from the herd on upgrade options

ill do that!

1985 4x4 F150 Flareside 6L Manual 4 with Granny gear

fljab

Re: Help from the herd on upgrade options

In reply to this post by 1986F150Six

I have a '81 with a 300 and the SROD and originally had the 2.47. It was "horrific" driving and basically couldn't use 4th gear (OD) except under very narrow circumstances. Like, no hills, no wind, and willing to keep the pedal to the floor most of the time.

If this truck has a 3.00 or 3.08, my opinion (for what little it's worth) would be to keep the granny low 4 sp and spend the money on a new/rebuilt transfer case. If the goal is to keep up with 75+ mph traffic on the freeway in a bigger metropolis, then you may want to rethink the situation. I just "putt" in mine, and folks in a hurry just go around me like they do big trucks.

My truck is happy now that I changed rear gear to 3.50. The SROD is no heavy duty trans, but for what I'm using it for, is just fine for now. As has been said on FTE, I scored a toploader transmission and thinking to put that in to have a good reliable one under the floorboard. If I do that, then will accelerate looking for, or purchasing a new/rebuilt 3.25 3rd member for the rear end. 300s don't like to rev, and for the way I drive, that should be just fine.

Jim
Mims, FL

'81 F100 2wd 300 Srod "Festus"
'85 F150 Supercab 4x4 351 C6 "big Whitey"
'85 F150 4x4 300 NP435 parts truck

Gary Lewis

Re: Help from the herd on upgrade options

Administrator

Good advice.

Gary, AKA "Gary fellow": Profile