1st post and question about rear gears

[squirrel64]

hey guys,

My first post here. I did some searching but I'm not sure what my best option will be. I have an 85 F350 4sp. A T19 tranny I believe. I changed the 6.9 out with an '88 7.3 about six months ago. My problem is that I pull a chipper and being loaded with chips I keep burning up clutches. Truck is just geared too high.

Clutch is slipping bad now but I really need this truck for work. So my first order of business is to order a good clutch kit from Fort Wayne. Now since I don't have the dual mass flywheel, I was wondering if this heavy duty model would work.

http://www.fortwayneclutch.com/inde...325-pn-s-07-131kdf-07131kdf-kt07-131-kdf.html.

They also have another model that I take is not quite as heavy duty.

http://www.fortwayneclutch.com/inde...07-131n-mhdk-07131n-mhdk-kt07-131-n-mhdk.html.

Will one of these be a good option for me ??

Second order of business is to either change gears or swap whole rear. I am assuming it has 3.55 in it now and was wondering what my best option would be in this situation.

I need to get a clutch in right away but the rear will have to wait about 2 weeks so I'll just take it easy on new clutch in the meantime. I could really use a little more heavy duty truck but funds are not available at this time. I really like this truck and want to keep it, but I have to resolve this problem and really appreciate any input.

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[fordf350man]

welcome to the site, there should be a tag on your rear axle to let you know the gear ratio in the axle, it will be on one of the bolts on the differential cover, now about burning up clutches im not to sure about a heavier duty clutch but if its a work truck and thats its purpose i would put a zf 5 speed in it, stronger transmission, lower grear ratio so it will handle the weight much easier and not slip on you so much, others im sure will come in soon and offer there opinion, listen to them haha lots of good information on here all from experienced poeple,

 

[squirrel64]

One of my ford mechanic buddies told me the same thing about the zf 5sp. I was a little skeptical that the 5sp would make that much difference. I really need some low end grunt on this thing. I don't care if it only does 45mph just as long as I can pull out of yards with a full load of chips and chipper behind it. As of now, if I have load on it I have to drop chipper and hook it up to my pickup and pull it out. With my bucket truck on the job that means three vehicles. Just a PIA

 

[icanfixall]

Welcome to the forum. Please find out what gears you have before trying to change them. It would be kinda silly to change to 4.10s and find out thats what you had all the time. I think changing out the complete differancial with another is the simplest because you have only the spring bolts and the driveshaft to remove. The shocks and brake line is simple too. But know for sure what you have now and what you might be installing. Someone here changed their gears and found out they did nothing but installed the same they took out. Kinda imbarrassing if you ask me.. Funny too..

 

[squirrel64]

ok I will have to jack it up tomorrow and get the ratio. There is no tag that I can find.

 

[lindstromjd]

Or, you can just plan on putting a 4.56 into it and not worry about if you're replacing your existing gears with the same gear ratio. The biggest thing though, is for you to find out what axle you have. Is it a Dana 60 / 70? Or is it a Sterling? You can check your rear hubs and brakes to figure that out. If the brake drum comes off without having to take the whole hub off, you've got a Sterling. If the whole hub has to come off to get to the brakes, it's a Dana.

 

[Shadetreemechanic]

That appears to be a cab and chassis model. One of those with 3.55s would be pretty rare I think. If your b pillar sticker is still on there you can also look up the axle ratio from the code printed on it.
Only the late model zf-47 will help you with low end grunt. The earlier one from 88-94 has a pretty tall first gear.

 

[chris142]

Are you starting off in 1st gear? Mine is plenty low geared in 1st. No need to give it any throttle to get moving. You could add a transfercase and stick that in low range to get moving .use it kinda like a brownie. I have done that playing around with mine. Adding a transfer case would allow you to keep your fwy speed.

 

[cpdenton]

I have a late model zf in my truck. 5s-47 out of a 97 stroker. With 4.10s in the rear, first gear is good for about 8 miles an hour wide open. On the other hand. I can let the clutch out without applying throttle while pulling my 7000 pound camper.might be worth looking into. I believe my first gear is 5.72 ratio.

Good luck and welcome to the site!

 

[squirrel64]

Oh yeah always starti in first Chris, and a transfer case...... interesting option ( a good option)
Fully loaded with chips is 3-4 ton
Chipper weighs 4000lbs

The axle code on the door jam says "69"

And thanks for the info on the ZF-47 I will look into that as well.


Ok found this in another thread for axle code

"69- Ford Ford Sterling 10.25 dual rear wheel 3.55 ratio (8250 rating)"

So now that I know that, where would you all start if this was your truck............ And thanks a bunch for the help and suggestions

 

[lindstromjd]

69 means you have a Sterling with a 3.55 gear. 4.10 would be a nice step up for you, or even a 4.56 since you don't care about highway speeds.

And it looks like you beat me to it on your edit. But the Sterling is a lot easier to replace gears than the Dana, in my opinion. To do it yourself will cost you about $400 for a brand new kit with new bearings, shims, and gears.

 

[riotwarrior]

Just a few things to get you on right track...

Chalk mark the tyre on the ground so you see a mark on tyre sidewall and ground. mark driveshaft yoke on differential and differential with similar mark. Have someone ( SLOWLY ) drive truck forward in 1st whilst you count the drive shaft revolutions until one full revolution of tyre. That will give you axle ratio EG 3.55 or 3.73 or 4.10 etc easy as pie to follow that and find out axle ratios on front or rear diff on any vehicle

Second, look around for a Brownie box that offers LOW DIRECT and OD

A tcase would work too but like a Brownie box it would need to be a divorced mounted one seeing you have a 2wd truck

Also a Advance adapters underdrive or overdrive could be used with the T19 it fits in front of the T19 between the bell housing and transmission. You would just need corresonding shortened drive shaft new shifter hole and move the transmission mount backwards.

One final option if you are satisfied with current top end is swap out for a different transmision like a T18 or NP 435 both of which can be had with very low first gears.

Lastly a ZF be it S42 or S47 is a viable swap as well. However, that entails a NEW clutch setup again, and that will entail a futher expense along with corresponding drive line changes and transmission tunnel too.

I'd suggest the Brownie box as your best option, IMHO because one thing you have not mentioned is what powers the hydraulics on your dump, if that's a PTO then a transmission swap means a whole new PTO if that is run off your transmission.

JM2CW

Al

 

[icanfixall]

A real easy way to determine what gear you have is do this. Jack up the rear end. Make a chaulk mark on the drive shft and the tire on the inside and on the ground at the tire mark. Now turn the drive shaft till you see the tire make one complete rotation. Count how many times the drive shaft truns. 3.555 is just a little more than 3 1.2 turns and 4.10 is just over 4 turns. Really the best way for sure besides removing the gears. They have the ratios stamped into them too.

 

[Shadetreemechanic]

Oh yeah always starti in first Chris, and a transfer case...... interesting option ( a good option)
Fully loaded with chips is 3-4 ton
Chipper weighs 4000lbs

The axle code on the door jam says "69"

And thanks for the info on the ZF-47 I will look into that as well.


Ok found this in another thread for axle code

"69- Ford Ford Sterling 10.25 dual rear wheel 3.55 ratio (8250 rating)"

So now that I know that, where would you all start if this was your truck............ And thanks a bunch for the help and suggestions

Ok sounds like you do have a 3.55 cab n chassis. Too bad you are further away, I have 4.10s in my 85 and would love to swap with you.
As long as you don't do much on the interstate, an axle swap is by far the easiest solution mentioned here. My 85 had a t-19 in it when I got it and it would pull a house down, but top speed was about 60. that was why I changed out to a 5 speed.
In my opinion switching to a 5 speed without changing your rear axle will be very disappointing. My 94 is a 5 speed with 3.55 gears (older s-42) and I do burn clutch on hills loaded unless I use my transfer case.
You shouldn't have a hard time finding a 4.10 axle for that thing. Just make sure it is a dually from a cab and chassis not a dually truck. The spring perch locations are different. You will also need to change the speedo gear when you do the swap, but that is cheap and easy.

 

[fordf350man]

if you do have 3.55s the cheapest way in my eyes would to swap out the axle with a 4.10, in my opinion i would get a limited slip sterling if you go that route, a zf swap would great but is pricey unless you find one with the right price, you can pick up a sterling for a couple hundred bucks