Hi everyone. I'm new to the forum and am looking for general info and imput. I have a 1991 Explorer with a 3" body lift and 32" baja a/t tires. I lost quite a bit of power doing this. It also has an automatic tranny and it is the four door version. Was going to redo gearing in the differentials, but not enough room to fit bigger ring gear. (just my opinion) Instead made home air intake system out of 3" pvc, big improvement, still low on power. Also took engine driven clutch fan off and replaced it with a thermostatically controlled electric fan. Huge increase, better gas mileage. My idea now is to swap in a standard M-50d into it because I know how much automatics can rob power. Got two standards, one that was out of a 90 Ranger, two wheel drive and the other out of 91 explorer. The one that is two wheel drive won't work because the main shaft is different to a four wheel drive. The other tranny had a blown reverse gear. The two gears in the back of the tranny were just eaten right alive! does anyone know why this happens? Any ways I took the 5th and reverse out of the two wheel drive and swapped it into the four wheel drive. And yes they were both the same ratios just in case you were wondering. I've got all the goods to make the entire swap including new clutch kit, slave cylinder, rear main oil seal(while i'm in there). I have read through the last years posts on m-50d tranny's and its got me a little worried. Is it going to break when I put it in? Will it be able to pull the bigger 4-door version without me thinking is it gonna make it? Is everyone on the internet just talking about m-50d behind v-8's? I know i would not trust it behind a v-8. I,ve got about $700 into it and don't really want to ditch the idea but the auto I have in it now is still going strong at 73,000 miles. My ranger is a 96 spalsh, 4 cylinder with an m50d with 68,000 miles and no problems so far in the two years I've owned it. Is it the way people drive them that kills them, afterall don't you think ford would have ditched the idea if it didn't work. Need imput because i am somewhat confused. Thank you!

 

Someone must have an opinion on this subject?

 

I think the M50d will be OK as long as it is not abused. I have it in two trucks one has 109K (I6)and one with 90k (V8.
Both holding up real well.
I know the shift forks are a weak link, they are aluminum and when you hold the shifter when going down the road it wears the fork out. if you have the tranny out, you should check them.
I replaced one on my v8 at 70K when I finally changed the tranny to a 4x4.
I have been running 36's on the v8 for 40k miles.
If you are low on power after a lift, you should check your rear end ratio, you should have at least 3.55's in it probably 3.73's.
there you will see the biggest increase in power.
A friend of mine ran 4.56's with his 35's on his ranger.
a lower ratio doesn't mean the ring is a bigger overall diameter. they are somewhat different in size, but to lower the ratio you lower the teeth count on the pinion and increase the ring. the ring usually just gets thicker. The only limitation you have is in the carrier until you get into super low ratios. The stock carrier will only allow up to a certain ratio. For example you can put up to a 3.90 in a 8.8 rear before you have to change the carrier. It depends on the rearends. Any gear supplier should be able to tell you how low you can go. I got good prices from drivetrain direct.
Good luck,
Aaron

 

[updated:LAST EDITED ON 05-Apr-02 AT 09:05 PM (EST)]Hate to say but you would have saved yourself the headache of reworking the manual trannies with a ring and pinion swap for the same price from a reputable shop.

The M5OD is reliable enough, but if you're going to force it to rotate the larger tires, then it's not going to fit the bill. By going with the lower gear ratio (higher number) you'll actually reduce the wear and tear on all of the drivetrain.

Do you have the 4.0 or V-8, or a smaller six. The 4.0 and V-8's should come with an 8.8 (it will be more square in shape when you look at the diff cover), which should have a better gear offering. The smaller sixes should have the 7.5 rear (squattier diff cover)and may not be a ready gear swap.

In the long run you have discovered that better air flow will give you better performance ;-) .

-Kerry