700R4 leak

[ohio hab]

You will have to pull the transmission to replace the front seal. I also have an 700r4 in my truck, after blowing out 2 front seals, the 3rd time I found a builder, who put a homemade retaining plate over the front seal. Being from Toledo, Ohio area where these transmissions where made, the builder worked at Hydromatic, the plant that made these transmissions. He put's these plates on all his performance build's. Good Luck, Ken.

[swilliams]

Yeah being here in New Mexico we don't manufacture much of anything. I wonder if this is just a start of a long line of problems. Would not having the TV cable adjusted correctly have anything to do with it? Maybe i should just have the entire thing rebuilt.

[bd]

Refresh our memory - what year is the trans and roughly how many miles are on it?

[swilliams]

I pulled the paperwork on it . Time flies.... 6/01 700r4 reconditioned + TC . paid $517.33. 13+ years i guess i cant complain. The RPO code is a MXO 4-spd. auto. o/d trans. which i assume is a 700r4 but i dont know if this is the original or not.

[bd]

All the factory upgrades should have been completed by the last repair... although, some aftermarket upgrades were released as recently as ~2012.  Determine where the leak is before deciding on a repair course, then if you are unable to correct it yourself, take it to someone reputable.

[swilliams]

I have not taken the truck an a trip longer than 40 miles in i dont know how long. Should i stay with the 700r4. I am also getting ready to up grade my heads and rear end.

[bd]

I would retain the 700R4 (aka: 4L60, MD8).  A properly built 4L60 will manage 500 HP/500 lb-ft with no ill effects - more than that by the right builder.  If you were planning on twisting it with a performance BBC, I would consider a different tranny.  But, a mildly modified small block, no worries.  There are plenty of references available to become familiar with that transmission.  If you are shy about fixing it yourself, just find a reputable (preferably local) builder.

But, again, don't let the cart lead the horse.  Find out what the leak is.

[swilliams]

Thanks for the advice.

[swilliams]

No signs of a leak running down.

Nothing running down the front of trans where the front seal would be.

A little closer but bad pic.



No connection leaks



Paper label on torque converter no trans fluid on it
The only clue i got is the fluid in the dust cover.

Is it still possible that the front seal is out?

[bd]

Relying on unclear pics - a WAG is pan gasket or front pump o-ring.  Although, that is a lot of fluid for either of those, under the circumstances.

Leave the dust cover off and add dye to the trans fluid then use a UV lamp, checking it periodically while it sits stationary over 3-4 days....

If the pan is leaking, install a sand cast aluminum pan such as a Hughes Performance HP3780.  The pan will never leak again AND it will strengthen the case.

[swilliams]

What type of dye do i use

[bd]

Tracerline oil based dye

Tracerline Optimax LED Light

The yellow filter glasses greatly enhance the effectiveness of the UV dye system.  Shopping around, you may be able to rent or find a similar product for lower cost.  I use Tracerline for difficult leak diagnoses with excellent results.  Fortunately, I don't need to use it very often.

[swilliams]

Thanks again for the help