351 C4 guys...question on front main seal lifespan

[Stang_ROTY]

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THe other day I had the pleasure of losing a front main seal on my C4 MIghtMite tranny from Dynamic Racing while shifting hard from 2nd to 3rd. Big smoke show

I have about 2000 miles total on the combination over 3 years and about 35 passes at the strip. Been a VERY reliable setup. I'll be yanking the motor ASAP to replace seal. Cause for concern or typical wear?

[goodyear1984]

make sure there is no play in the shafts..also make sure the pump is not whats leaking

[Stang_ROTY]

By that you mean the input shaft? Is there any way to tell if the pump is the cause without pulling everything? I put about 2 gallons into it and about 5 seconds after I started it up it came pouring out the bottom of the bellhousing

Originally Posted by goodyear1984

make sure there is no play in the shafts..also make sure the pump is not whats leaking

[goodyear1984]

u really have to pull it out and inspect it what ever it is should stick out.

[goodyear1984]

you could do a pressure test but with it leaking like that it would be point less ,,,plus u dont want to run it low on fluid and have to replace the clutches and bands

[Stang_ROTY]

Yeah that's a good point about running low on fluid. I lost all 3 gears when trying to get her home during the massive leak. Ended up about a 1/4 mile away when I lost all my gears. Tranny was bone dry. I'm running a temp gauge and didn't notice any increase in temp so hopefully it's ok internally. I'm going to bring it back down to Harold at Dynamic Racing to have them look at it. I went with the automatic setup over a 6 speed b/c I figured it'd be more reliable. But maybe the 2500-3000 rpm traveling on the highway to the track hurt it? I can't imagine 30-40 12 second passes on a tranny that's made for 8 second Stangs did any abnormal wear.

This wasn't a cheap tranny at all...I'm a bit surprised (and disappointed) that seals are going this soon.

Originally Posted by goodyear1984

you could do a pressure test but with it leaking like that it would be point less ,,,plus u dont want to run it low on fluid and have to replace the clutches and bands

[theracinjason]

Sounds like a pump gasket to me. this is notorious if you have a small bellhousing. this means the bellhousing bolts also hold the pump. if you bought it and had it shipped with no bellhousing im sure there were 2 bolts holding the pump in place. because in a c4 it has to be standing on its tail to install the pump. if you take the pump or bellhousing bolts out (all 7of them) it is absolutely imperative the trans is standing on its tailshaft. you will need a buddy or a special table or a post in the garage with a ratchet strap. what i have done in the past isstand up the trans, remove the 2 countersunk bolts, if your trans builder used them. then bolt on the bellhousing using all 7 bolts instead of just 5 left if there are countersunk bolts from the builder/shipper. if you choose not to do this, make certain you torque in sequence and go a little more than Ford's reccomended 28lbs. i like 35 and have not had a recurrance since.

[FastSmitty]

I was wondering anything if you found out what the problem is? On my new Art carr tranny.... same issue.... Wow when everyone said pump i thought it would be something easy to get to but looks like i will have to drop the tranny.... so I guess it is the main seal or the pump.... so yea fun stuff.....