Ok I have a 91 bronco with 5.0 e4od stock gears and tires are 31-10.5-15. The trans seems to be getting hot fast. New fluid and its full. 3rd and 4th are sloppy on down and up shifts. What would cause trans to over heat? No slippage just feels like its falling in and out of gear. It shifts ok when its cool but after it gets warm bam sloppy and the longer I drive it the worse it gets. Feels like it looses power. I am only getting 10mpg tops. I am looking at swapping the auto for a five speed. What all would I have to change? Computer and wiring? trans case? I hate the auto!! Or if I can salavage this trans how can I get it to shift better?

 

It kind of sounds like inner seals are getting warm and failing leaking fluid inside places where there isn't supposed to be fluid. It sounds like you need a full rebuild. My c-6 (much more basic mechanics) was doing something similar and it was because everything inside had been worn out. The clutch disks were worn pretty far and the fluid was a gross brown when we drained it. Thats about what i can suggest, i don't know much about the E4OD's.

 

On my 1990 with 165000 miles, I usually put the trans in D without the overdrive. I only use the overdrive once I get up to freeway speeds.

Also I towed a two horse trailer with one horse in it, 250 miles, had to downshift on the hills but it ran 70 miles an hour on the way back, after I dropped off the horse trailer.

There seems to be a slipping in the trans if I put it in Overdrive right off the bat, that's the main reason I quit using overdrive except after reaching speed.

 

As for the auto-to-manual swap, you would do best to locate a complete 4WD donor truck of similar vintage (within 5 years either direction). The OEM 5-speed was the M5R2 (M5OD) Mazda-built unit. The ZF S5-42 (found in the 3/4 ton and bigger F-Series of similar vintage) will also work and is significantly stronger. Physically, it is identical in length and bolt pattern to the M5R2. Both are several inches shorter than the E4OD (which was by far the largest transmission put into these trucks). You will need to swap driveshafts or have lengths changed... shorter up front and longer out back. These are OEM lengths so replacements are available but may be more expensive than having old shafts altered. No matter which unit you swap in, you MUST have a 4WD version! Both the M5 and ZF were available in 2WD versions and the 2WD units cannot be made to accept a 4WD transfer case!

You CAN keep the t-case but will need the intermediate shift linkage if it is a manually shifted unit since transmission length will change. You will need the cross-member for the M5OD or ZF. The rubber transmission mount in the cross-member is the same for both units. You will need all of the clutch equipment hardware including pedal assembly, master and slave cylinders. (These parts are interchangeable between the M5 and ZF). Always match clutch parts (except pedal assemblies) to the vintage of the transmission you are using and not the vintage of the vehicle.

You don't need to swap computers but if you have a complete donor truck you will have the right computer assuming the engine in the donor is the same as your truck. If not, you can simply leave the MLPS (Manual Lever Position Sensor) from the driver's side of the E4OD attached to the transmission wiring connector and leave it in "Drive". This will make the computer THINK the truck is always in drive and allow full engine performance/operation.

Having a complete donor will also give you a steering column for a manual rather than having the old "auto" column in there making people wonder whether to grab the column or floor lever to change gears. Since these trucks came equipped with both transmission types, the mounting holes for clutch master cylinder and other goodies are already in place. You will just need to remove plugs and covers to mount them.

You aren't necessarily limited to these two transmissions however, since they were OEM units and the ONLY 5-speed units available in these trucks, a swap to either of these units poses the least amount of potential fabrication and alterations to the truck as it exists now

 

Thanks for the info! As always very helpfull! Craigslist here I come. Wish I had kept my 5speed 4x4 f-150!

 

I got a M5OD I took out to put in my ZF5 in my Bronco.

 

Since we are on the topic of transmissions. Does anyone know of a person who was crazy enough to put a ZF in a 78-9? I would hate to see the list of instructions to do that...

 

New crossmember, new driveshafts, new trans mounts, big block zf5, probably will have to bend up the transmission hump a little near the firewall so the zf5 will fit...I've already talked about this in the dentside forum on here...costly.

 

Ah, yeah it's a dream but it would sure be cool to have a 5 speed in there... Heck a 4 speed would be cool.

 

ZF from behind a diesel or 460 will NOT work but not because it's too tall. The bellhousing bolt pattern is wrong. ZF has to be from behind a 300, 302 or 351W. As I said, the ZF S5-42 is a direct swap for the M5 which requires NO modification to the truck beyond driveshaft length changes which would have to be done regardless of what OTHER transmission you dropped into it. You just did this swap... Why am I telling you this? Skip it... I just read the part about doing this to a 78-79... I'm an idiot... disregard!

 

Well I found a 91 f150 4x4 5speed on craigslist. Its cheap and complete. I plan to swap out transmissions get the f150 running and sell it for tripple what I pay for it! Ive been under the weather for the past few days so I hope its still there! post results when its done!

 

Will the drive shafts work from a 91 short bed F150?? I believe I will have to modify the rear drive shaft but shouldn't the front one work? Do you know where I can order or get a drive shaft?

 

I'll put my @ cents in here.
You found a good donor. The clutch peadal assembly master and slave cylinder, as well as crossmember will work fine for you. Since you have the correct ECM change that too. I left part of the E4od harness under my '91 bronco and zip tied it up to the frame out of the way. Get out your tape and measure your shafts front and rear, you might have to have one shortened. I found one that was long and had a shop shorten it for me at a cost of about $35. This is a great time if you have any suspension lift or are planning some to get the length right. It is also a good time to change the slave cylinder! Spend the $$ and install a new one while you have it out because that used one might let you down at any time, mine lasted about 4 months and I was pulling the trans to install a new one.
Also I just cut the hole for the shifter out on mine, the factory hump would have been much easier. Still looking for a good set of shifter boots. Every used set I've found have been violated by mice and rot so far.
Good luck with the swap.

 

Yes, the front drive shaft will work since the F-series is the same as the Bronco out front. (I used the front driveshaft from my 92 F-150 donor -300 (4.9L)/M5R2(M5OD)- in my 93 Bronco). The difference is in the rear where the F-series driveshaft is obviously far too long and the original rear shaft, from behind the E4OD, in the Bronco will be too short because both the M5 and the ZF are about 2 7/8" SHORTER than the E4OD.

The E4OD measures 32 3/8" overall length and the M5 or ZF measure 29 1/2" in overall length depending upon who's information you read. (Some list the ZF at 29 7/16"... a 16th of an inch is not something I'm willing to quibble over).

 

I'm glad you have all these numbers available to you! lol
I also changed yoke styles. I believe my '91 had a slip yoke, the '89 donor I used had a fixed yoke. I like the fixed yoke because you can remove a damaged rear driveline without spilling fluid, 4 more bolts, no prob.
Oh yeah, almost forgot a minor issue I found the hard way, The starters are different between the manual and the automatic. So now have a small aftermarket high torque starter with no engine to start!
Good luck!
I found a professional driveline shop, not sure how close it is to you, http://www.inlandtruck.com/locations/stcharles-MO.php
I used a local welding shop that has fixed shafts for me before and I liked his work.