Hello all; newbie here,
I just abought a 2006 Mustang 4.0L automatic with 200k miles for $1k. The body is cherry, but has shifting issues- it won't go into R, and will run in 3rd gear. I've read a lot about possible overdrive sprag issues; so I know I need to overhaul the tranny.

I know the resale value is only ~$8-10K; but for me it's a project car. My budget =<$8k.

I'd like to ping ya'll for some advise and possibly where to source parts.

Here's what I plan to do:
1. run a compression test on the motor and see if everything checks out. I might pull the engine and get it overhauled or buy a refurbed motor.
2. Pull the tranny. I've never overhauled a tranny, so I'm getting quotes for an overhaul or buying a reman tranny. I'll replace the clutch and any bad seals while I'm in there.
2a. I've seen a lot of master rebuild kits, but I don't have (or want to buy) any special tools. Can this be done with basic tools? Maybe have an expert bore out the servos?
2b. I'd really like to convert to a 5 spd, but since I don't have everything (like the pedals, tranny, wiring, PCM, hydraulic clutch, etc.)- this may be over my capabilities.
3. Upgrade the suspension- it probably needs struts/shocks/bushings anyway, so why not. I'm comparing airbags vs. a coil-over handling kit.
4. Check out all the subsystems- I think there are a couple worn out interior switches (windows) that need replaced.
5. Drive it for a couple months, sell and start a new project.

Any recommendations?
TIA, Motorheadrulz

 

With these cars, I can't even imagine wasting the time and money it takes to open up an engine or trans. There's plenty of good low mile used replacements for almost no money available. Performance is limited with the 4.0L, even with boost, so something I've been thinking about doing (that I haven't seen done) is an ecoboost swap. That $1000 chassis, plus a 2.3L ecoboost engine and trans, and a 400HP turbo kit would give you a seriously fun car for less than $10k. Converting an auto to a manual would be challenging, but not out of the question if you can source the parts from a junkyard.

On the suspension thing, these cars handle damn well from the factory. Air bags suck for too many reasons. Coil overs are nice for setting ride height, but you can get similar performance with a good set of shocks/struts and some lowering springs at a fraction of the cost.

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CJ just gave me an idea. And yes, the 4.0 is better replaced than trying to build/rebuild one.

But what about swapping in the 3.5L V6 EcoBoost?

 

There's been a few people who have done that with good success. There's a video out there from MPT where they dyno'd a stock F150 3.5 eco in a Mustang with a manual trans, and it made 370 rwhp with the stock tune. I think they ended up with something like 450 rwhp on pump gas after doing a custom tune.

Only problem for me with that combo is that it's too heavy. Virtually the same weight as a Coyote, which totally changes the character of the car. Might as well just go buy a V8 car, or do a V8 swap.


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I understand the cost-benefit ratio of just buying a GT. Remember this is a project car. I've been working from home for the past year and I'm bored out of my skull. My landscaping, painting, and other honey-do's are done...

But I'd really like to know if the tranny master rebuild kits can be done at home, or just buy a reman tranny ($1800)?

I did airbags on my F250, so I have the experience and I loved them for hauling/towing; but I know upgrading shocks/struts are cheaper.

I'm still forecasting <$6k total for this project.

 

The 5r55s tranny is a very fickle transmission. If you don't rebuilt it right it will still run poorly. Buy a remaned one with a warranty instead of trying to rebuild it yourself, unless you have good experience rebuilding transmissions.

As mentioned, the time and effort spent rebuilding the 4.0L might be better spent on a different engine.

Fordtechmakuloco did a four part series on the 4.0L pulled from a ranger on just the timing. This guy lives, eats, breathes and sleeps Ford repairs for a living. He is a master tech for Ford for X number of years and now has his own shop dedicated to fords) Even he called it an overly complex process.

 

I've rebuilt many auto transmissions, but never one of these. If the kit is cheap, and you're looking to learn, then sure why not? If the rebuild kit costs more than a used low mile replacement, I wouldn't bother. Same for the engine. Get a used low mile replacement from a junk yard, and spend your time/money on upgrades. I know I saw a twin turbo kit for the 4.0L for something like $2500.00, or you could just stick with bolt-on stuff like intake, headers, exhaust, nitrous, etc.


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thx for the links- it was helpful.

So far I've spent $1k for the car + $40 for a Chilton guide.

Master rebuild kits ~ $350; still need to bore out the servos. I'd still prefer to have a pro do this...so, after watching a couple how-to rebuilds, I'm going to drop the tranny and get an estimate for a pro to rebuild it. If it's < $1500 OTD-- easy answer.

Reman trannies from Autozone= $2300; but I can't tell if the output shaft is the correct # of splines or whatever small parts are not included. So I need to pull the tranny to make sure I get the right part.

I've also found some auto - manual conversion kits on Ebay for $1700 + shipping. Everything is included.

More to follow in the next few weeks... Thanks guys!

 

Link to those conversion kits? I have an 07 V6 auto and I've been toying with the idea of turning into a project car. Bought it new, and it's been the wife's car, but she wants a Flex now. Could sell my 13 Mustang to pay for the Flex and take her 07.

Take a look at car-part.com and sort by distance for an engine or trans. You might get lucky and find something nearby for very little money.


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<Link to those conversion kits?>
Just search on Ebay. I pinged them for my 2006 and they didn't have a kit available. I'm searching junkyards from your link for a donor drivetrain.
Thx and Good luck