Transmission conversion


Asked by Oct 02, 2013 at 11:34 PM about the 1989 Ford F-250 XLT Lariat Standard Cab 4WD LB

Question type: Car Customization

'89 F250, 5.8l 4X4. i have a 4 speed manual with 5th gear OD but can only handle towing up to 4000lbs stated in owners manual.
im wondering if there is a aftermarket gear i can put in to have 5th gear and maybe a 6th gear. going 50mph at 2500rpm on
highway hauling 4000+ lbs is not ideal. and sucking fuel down to. or is there a 5 speed or 6 speed trans that will mate up to the

19 Answers


or is it easier to swap it with a cummins with a 6 speed, that is all i am finding on the web.


Dodge runs the cummins diesil not ford. And the Ford diesil was never that good on milage. The power stroke


I know I do not spell good

Transmission 3-speed Ford C6 automatic 4-speed automatic Ford AOD Ford E4OD 4-speed Borg-Warner T18 manual 5-speed manual Mazda M5OD ZF S5-42


Good luck finding a C6 these days Hard to find where I am from

2 people found this helpful.

The towing capacity isn't just because of the transmission. The engine, frame, springs, rear axle and tires have a lot to do with it too. The 5.8 isn't suited to big loads like that. It will pull it - you'll hate it - and it will eat fuel. You don't want an overdrive unit when you tow because you will burn it out. To be brutally honest: If you would like to tow a big load, buy a big truck with a big engine - if you want fuel mileage - buy a car.

1 people found this helpful.

In 4th gear the input and output shafts rotate at the same speed. With an overdrive, they rotate at different speeds, which under load (like towing) it wears it where the 2 shafts are joined at an accelerated speed causing transmission failure. Best bet would be invest in a newer ecoboost which will tow over 10, 000 lb & still get decent mileage.

1 people found this helpful.

the truck tows a 33ft cabin cruiser and a 26 ft front cabin open fishing deck boat just fine, dont need a bigger engine, just need another gear over 4th. i dont want a automatic, i like controlling my rpm. i know towing over 4000 lbs will burn the OD gear, says not to use it in the manual. im just trying see if there is a 5 speed manual or 6 speed manual match up to the 5.8l, that will help on fuel consumption because engine will be at lower rpm then with the extra gears. a car wont haul what i need it to haul.

1 people found this helpful.

It's a 1989 this is 2013 I think it has seen it's better days. They are nice old trucks but they need to retire at some point to.


changing axle gear may help right? i dont have money get new truck right now.

2 people found this helpful.

It could but rember you have 4 wheel drive you have to change all gears not just the rear end you have to do the front end all so and that is not cheap to do. My son had a 1989 f150 with the 4: 11 gear ratial with over 300,000 on the 300 inline 6 in it beforwe scraped it we pulled front and rear difs out so they were a matching pair they were both true possie. we sold the rest of the truck for scrap and got $250 for that and got $3500 for the difs because of the true possie and gear ratial

1 people found this helpful.

mine has 115000 miles. i dont know what my axle gearing is. i know have to change both.


should be a tag on the front end and the front dif to indentfy what the gears are.Get them and maybe call a local ford shop or trans and dif shop and they should be able to tell you what you have


or maybe even try looking in your owners manual if you still have it. That may tell you or call a local salvage yard they can maybe tell you what gears you have. Just need to know if it 6 bolt 8 bolt rim pattern that makes a big difference


all so count the bolts on the rear end pan That should be a drop out rear end. what I mean is you can pull the whole pinion gear assembly out of the back of the rear and front end axel assemblys

No. ron....Old Trucks Never Die!~

2 people found this helpful.

every thing doe's when its time is up even us. You can keep rebuilding and repiaring but some time its more money than its worth. But I hear ya on that one

My 1978 F250 will pull a train.To this day.

Your Answer:


Looking for a Used F-250 in your area?

CarGurus has 396 nationwide F-250 listings starting at $4,995.


Ford F-250 Experts

  • #1
  • #2
  • #3
View All

Related Models For Sale

Used Ford F-150
2,356 Great Deals out of 208,288 listings starting at $998
Used Ford F-350
209 listings starting at $8,999
Used GMC Sierra 1500
746 Great Deals out of 61,254 listings starting at $1,395
Used GMC Sierra 2500
126 listings starting at $4,200
Used Ford Mustang
260 Great Deals out of 37,873 listings starting at $1,350

Used Cars For Sale

1996 Ford F-250 For Sale
53 listings starting at $4,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.