i have a 1993 ford f 250 300 i6 the truck has 115000 on it with a c6 trans it has no over drive the truck runs great but just today on my home from work the truck shutterd i thought it was the rear end hanging up i got the truck home and soon notice that when i put the truck in drive and reverse it makes a winding noise the trans has never sliped or showed signs i had it bg flushed at cottman transmissions i put it on jack stands and herd the noise comeing from the tail of the trans does this mean the trans is going to need to be replaced? if so do they make a over drive c6 or should i put a c4 at 55 mph the motor turns 3000 rpm the truck sucks down gas and is slow also i would like to put a 351 carb motor in it i live in charles county md if i put a smog pump on it would it pass emissions? thanks Daniel

 

The noise could mean a rebuild or replacement is required. Only further diagnosis will tell. Do you know a trans shop that you trust, or do you know anyone to get a referral from?

C6s are reasonable cheap compared to OD trans, so get estimates from a couple of places. You can have yours rebuilt or swapped out.

That is, if it needs a rebuild--back to the trans shop question.

There are no OD C6 or C4 transmissions.

An AOD trans will bolt up to your engine, but these were trouble early on. An '88-93 unit from a V8 truck is the best choice, V8 Car next best, Six truck ok too. These need to be checked and set up properly as there is a throttle valve link or cable that is vital to proper operation. (improper adj. or no cable/link = quick trans failure)

As for a 351 carb motor--your truck will be quicker, but use the same or more gas. If you have emissions inspections, there must be a standard that your state uses. Do you simply pass at the pipe? Do you have a visual inspection? The "usual" standard is that the vehicle meet the standards in place when the vehicle was sold new. That means pumps, cats, egr, whatever would have come on a 351 F250 for your model year. You need to check with the smoggie about that.

Back to step one: Have the C6 diagnosed.

 

2wd or 4wd? If 2wd I might have a tranny for you, near your area

 

I love when people say stuff like "I live in charles county" like the rest of us are familiar with all the counties in every state in the US.

Anyway, what do you mean by "winding noise"? Are you sure it isn't a u-joint?

 

no its a 2 wheel drive it still shifts fine in every gear i dont think its the u joint becuse of the noise i hear is comeing from the tail of the trans and if i put my hand on it and spin the wheels on jack stands i can feel something grinding in it i drive the truck every day 30 miles to work and back and it never slips i plan on pulling my dads 21 foot boat tomorrow i guess 5000 pounds will tell me if its bad or not could a torq converter do this my 95 dodge ram 12 valve does make a hard grinding noise when i put it in reverse but it still has power even pulling with the turbo spoling up hard my frinds said its a torq converter i dont know thanks for your help Daniel

 

Well, if it grinds and you tow with it, you will probably resolve the issue of minor repair vs. rebuild. Good luck.

 

well it pulled fine for the 15 miles to and from but is still doing it it only does this when you come to compleate stop and when you take off it shutters but then goes right away is it normal when iam doing 55/60 mph the truck turns 3000 rpm cause that cant be good on the motor does any one think thats normal if i put a smaller ring gear in it and take out the 4.10 and get a 373 rear for it would that get me more speed just enough to keep up with the flow of traffic and if i was to put in a 351 would it still turn the exact rpms as the 300 i6 with stock trans and rear whats a stock f 250 with a 351 turn at 55/60 mph

 

the 410 rear is what makes that f250 ok with a small 6 - it can work as long as you are not in a hurry.

 

yeah but on interstate 95 and 210 you got to go at least 65 mph what rear end would be recomended for a 351 f 250 4x2 and how diffacult would it be to put a 351 in would i have to change the drive shaft or any thing besides the motor mounts and wireing harness would it bolt up to a c6 and should i put a smaller rear gear in it or should i go with a pro 5.0 motor would i get better top end than a 351? thanks alot Daniel

 

if you change engines, but not trannys, the driveshaft will never know (unless of course the I6 motor mounts force a tranny motor mount change - I have never done that)

If you absolutely must have 12mpg, then do the 351. Best idea is to put in a 4spd and lower the highway top end. f250 is heavy and is capable of doing heavy things - even with an I6

to get a top end worth feeling with a 5.0 you gotta see around 300hp

 

isnt a c4 the only 4 speed ford made for these trucks and they were not as strong as a c6 i know the 300 i6 is built for torq i think it pulls my dads 21 foot boat better than my 95 cummins ram but if i was to put in a 4 speed and keep the i6 would it still be strong enough to pull whatever i ned something that aint gona wind out so bad because when i take my foot of the gas the truck slows down real fast and if the 4 speed is the way to go what do i have to do to put one or will mount right. Thanks for all your help daniel

 

A C4 is a 3 speed automatic, no OD, no lockup torque converter. It will perform in almost exactly the same way & run the same rpms as your C6.

You could change to just about any gear with the 6, same with the 351. It is going to affect you either on the top end, like it is now, or the bottom, as in making your first gear very tall.

With a 28 inch tire, the 1:1 trans, & 4.10s, you should be turning about 60 at 3000 rpm.

With 3.25s, you will turn about 2340 rpms at 60.
With 3.73s, you will turn about 2685, 3.55s about 2556.

You should still be able to pull with 3.55s or 3.73, perhaps even up to the same weight, and still be able to pull top gear no problem with the load.

An axle ratio change is less work & probably less money than a trans change, which, unless you get an OD trans (not cheap for a beefed AOD, not cheap at all any OD) is the only way to reduce revs.

As for the 351 swap, that won't do anything for revs unless you change the axle and/or trans.

 

what would have to do to put in a 3.55s or 3.73 rear. Thanks Daniel

 

You need a gear set, about $200, and as long as you are having the axle done, put new bearings in there, and labor to swap it out. $500 would not be unreasonable to expect. Some have quoted much higher.

Find out what kind of axle you have--probably a Dana 60--and shop around. Be sure the shop has done these axles before. Ask them flat out how many they've done. You don't want the guy to learn the Dana axle on your dime and on your truck.

Your axle code is in the codes found on the door plate. You can post that here and have a good chance of getting a decode.

 

thanks for your help its a 13 bolt rear on the door plate it says axel 35 and springs cf don't know if i need that and the trucks vin 1fthf25yopna59008. ive thought about doing it myself to save money ive done axels and hub bearings brakes etc but ive never done a ring and pinion the biggist thing is get everything torq down right and the shim packs right or would you think its best to let somebody whos done one to do it and what brand would be the best to get a ring and pinion . also i had the trans looked at they said it seems to them that the u joints are causeing it to shutter at take off i thought when a u joint goes bad it would clunk when put into drive and reverse it does not do that it only makes a wineing noise when put into drive and reverse then it goes away.thanks for all your help Daniel