I have a 91 F150 with a 300 I6 and the high geared mazda 5 speed transmission and I need some pulling power. I have already changed the ring gear and pinion to 3.73. This helped quite a bit allowing the truck to pull itself, but it aint got enough stuff to pull a boat out of the water. I was wondering if anyone knew if there is a transmission with a granny that I can mount up without much trouble.

Beau

 

That depends on your definition of "much trouble". The ZF is the best manual you can get, but it's priced that way, too. The NP-435 is bulletproof, but doesn't have OD, so your top speed will drop significantly. The BW T-18/19 are about the same as the NP, but the 18 isn't synchronized.

http://www.motivegear.com/tech_info/...nny_guide.html
http://www.novak-adapt.com/knowledge...on_gateway.htm

 

Just had a thought. If a low gear is all you need to yank a boat up a ramp. Why not install a transfer case from a 4x4 behind your tranny. You can pick one up cheap. (cheaper than a ZF trans and easy to swap) Not sure but I think just the tail shaft is different on the mazda tranny in a 4x4.

Then you would have the best of both worlds. 5 speed on the highway and low range for when you need to go slow and pull or back a trailer. I use 2 wheel drive low in my truck all the time. It has 3.55 gears and I wish it was geared even lower. I can relate to pullin boats. When I get my new 22ft cruiser I am sure I will have to go to 4.10 gears. Would like to hear what you decide.

Chris

 

Good idea, shotgun. And along the same line, there's also the "Gear Splitter" and all the other bolt-on over/underdrive units.

 

Where would i find one of these bolt on gear splitters or underdrive units?

 

http://www.klunev.com/
http://www.advanceadapters.com/index515.html
http://www.gearvendors.com/

 

I have a thought. What would it take to put an automatic transmission in the truck? Will it bolt up to my 91 300? i know i'll have to run the shifter linkage etc, but what else on the drive train would i have to change? I guess the length of the drive shaft would probably change too? Any thoughts on this?

 

It's certainly do-able. Ford already made all the parts you'd need and the junkyards & dealerships are full of them. You'll need a steering column, a crossmember, a radiator &/or an aftermarket cooler, driveshaft work (as you mentioned), and you'll probably want to remove your clutch pedal, or change the pedal bracket to one with only a brake pedal. Any 4.9L, 5.0L, or 5.8L transmission will bolt up to your engine, but an E4OD will need a new EEC (computer) to run it - $180-250. An AOD or a C-6 (no overdrive) will only need mechanical or vacuum kickdown (respectively), which you can get at the junkyard with the transmission.

 

I read a post saying that the AOD is not a very good transmission, is this true? My truck has around 150000 miles on it. I expect the engine will last for a lot more. How will the AOD hold up?

 

Go to http://www.baumannengineering.com .

 

Not much trouble is a relative term. It depends on if you are performing the work or paying some. The gearvendors idea will set you back $2500-$3000 depending on how much needs to be done. A swap to a ZF will cost you around 2000-2500 depending on costs and if you perfrom this swap yourself. I think wou would be very satisfied with the ZF if you are going to be doing any towing.

I did my own T-18 to ZF swap so I do know a little about the costs. Someone will say you can by a used ZF for $1000 or a new for $1200. If you find the shop selling them for that buy 10 because the true costs (shipping, core charge etc.) are much higher.

 

Wow a post I can finally know somethig about! I am in the process of switching out my M5OD to a C6 in my 88 300 I6. I got all the parts off a 3/4 ton I6 donor truck. The get everything mentioned above and it is a direct bolt on! The onlt thing different I am doing is the shifter. I am going to use a floor mounted shifter to fill the hole left by the 5-speeds shifter. The best thing is a friend of mine was wanting to use the donor truck to convert into a trailer (it had bad front end damage) so I got all the parts plus some doors for only $300! Good luck.