Hello everyone, I have a 1986 F150 4X4 with 302 engine and 4 speed Warner T18 gearbox. The front end is Dana 44 and rear end is 9" with 3.5 gear ratio. I want to replace it to a 5 speed heavy duty transmission with 4X4 compatibility. I have looked into the M5R2 but hear that these are not very lasting option and will run into problems. The ZF 5S42 and ZF S547 are more reliable and heavy duty gearboxes.

What do you experts recommend and any suggestions on where to buy them.

 

Junkyard or craigslist... Online junkyard search as a last resort (because shipping will be expensive). When buying check for input shaft play. Finding one at the pick-n-pull is ideal so you can grab the crossmember, tunnel cover, and shift lever.

Edit: the S5-42 should be plenty of overkill for a 302. The S5-47's are pretty scarce. I would not go out of my way to seek one out.

 

When doing a online search, just plug in where you live. I went to Car-Part.com--Used Auto Parts Market and plugged in Georgia. Here are some hits.

1992
Transmission
Ford Truck F150 REMAN, 24mo/24k Warr $500 Core 0 A REM50157 $1875 WeaverParts.com USA-GA(College-Park) E-mail 877-809-8072 /678-783-1433
1988
Transmission
Ford Bronco 400.00 as is 001685 $550 Austin's Used Truck & Auto Parts USA-GA(Douglasville) E-mail 770-942-0468 / 877-942-0468



Not many showed up did they? If you live near another state, try that. If you want a zf 5 speed make sure you plug in a f250 or 350, and make sure you use a truck after 1988 or so. You will have to plug in a 300 six or a 351w so they will fit your 302. You may have to do some figuring on a clutch disc, they never offered the zf behind the 302 that I know of.

 

Thank you Ford F834 and Franklin2. So Zf 5S42 is the best option and should work as good as my T18 for heavy duty usage? Can I use my current transfer case?

Yeah, the 302 didn't come with these transmissions and was wondered if they would fit my 302. I know I will have to alter the cross member and possibly the shaft length.

There is a local S&S auto which might have transmissions. I will call them today and find out.

 

I forgot to mention that the primary reason is to get better gas mileage. I get about 8-10 in city and hwy now. I am hoping with an overdrive, I will get at least 14-15 miles/gallon. What are your thoughts?

 

My understanding is that OD is good for 2-3 MPG.

 

If you get 8-10 MPG with a 302/T18 combo with 3.50's then you have some serious problems that an OD tranny isn't going to fix. For comparison I get 10-12 MPG with a 351M/C6 combo with 3.50's front and rear, and a manual tranny like yours would probably boost that to 11.5-13.5 MPG. So a 302 should be more like 13-15 MPG when tuned properly.

So, I'd recommend you sort out the combo you have before changing to another tranny.

 

Thanks for confirming that. I have been talking to people around here and they all tell me that 8-10 is the best that I can get on my truck and I find that bizarre. My fuel injectors have not been cleaned after I bought the truck from a farmer in north GA two years ago. But then I don't see any problem while driving so I don't think that's an issue. Unless you have a different opinion on this?? I have changed spark plugs and checked fuel pressure. They all seem to be fine. I put new tires and wonder what else I need to look into. I also removed the fixed fan and installed electric fans.

Does your truck run on carb or fuel injection?

 

That's good to know, thank you.

 

Since it's an EFI engine (computer-controlled) you might pull the codes and see what the computer thinks is happening; 1986 is too early to have a Check Engine light so you can't use that to determine if the computer thinks everything is OK or not.

 

Amen!

My truck is carb'd, but an EFI'd 302 should get much better MPG than mine. Even if you flog it and try to run 75 and 80 MPH it shouldn't get that poor of mileage.

 

Khaitan: I have pulled the codes and everything seems normal. It does not have any errors.

 

Khaitan: see this is the difference. That's what I am told if I put a carb to my engine I will easily get 13-14. Because this fuel injection is one of the first Ford introduced on these trucks, they are not very efficient. I am in the process of installing the fast EZ-EFI 2.0 fuel injection to improve performance.

 

The only problem with the early EFI's was from the way they measured or determined air flow. The early ones inferred the air flow by assuming things about the engine. But, if someone changed anything on the engine, such as changed out the cam, then the EFI system made bad assumptions and the air/fuel ratio was off. But, in that case the O2 sensor should catch it and throw some codes. Later systems actually measured the air flow via a mass air flow sensor, and they have much more tolerance for engine changes.

The FAST system should help significantly, unless you have other problems like poor compression, blown head gaskets, etc. Or, unless you are running a really long-duration cam, but even then your MPG shouldn't be that poor with a 302.

 

Thanks Gary, I will have to check whats going on with the engine. I know that I lose compression in the low gears but the truck flies when I get to the 4th gear. It is also drinking little oil but I think thats normal for an old engine. If the head gasket is bad, then the smoke will be white but that is not the case either. My guess is that the injectors are the cause for this mileage to drop because I have no idea when they were replaced. When I bought the truck, the fuel tank was nasty with no filters. I cleaned the center tank and replaced the rear one. After that truck drives much better. I did remove the air smog pump recently and haven't closed the pipes. The initial pick up has gotten better but the mileage has definitely dropped further after that. Any idea how I can check the cam?