so i put this th350 in and drove it around, and it was workin awsome, shifting like a charm and otherwise just a beauty. i drove to town and around town, say about 2 hrs, on the way home i took the freeway and everything was ok, but after about 20 miles at freeway speeds i felt er slip. i made it down my exit and onto the shoulder and that was it no more go. i looked underneith and their was tranny fluid everywhere so i went to the gas station and put fluid back in er, but to no avail. i had reverse but no forward.
I left it sit over night so i could pull er back home but when i go there i started er up and drove it the 4 miles home but about a block away the go was gone again and i coasted into my driveway. my quess is that it overheated cause it doesnt have the normal tranny cooler but only a smaller add on cooler.

my question really is, does that sound like it overheated or maybe something else
and if it did over heat is there and easy fix or did i just sell myself a new rebuild

 

What's the history of the transmission? Is it a junkyard special or did you just have it rebuilt? As far as the trans cooler, I run just a B&M cooler with a 4,000 stall converter, it has never overheated on me.

 

well i got the tranny from a neighbor that had it rebuilt and stuck in a chevelle or somethin, then he said he did a whole motor and drive chain change and just left this tranny sit in his garage for a few years, he said he only put a few miles on it before he ripped it out.
when i stuck it in it drove like a charm. if it did overheat what would the syptoms be?

 

Don't think I've experienced an overheated trans, so I'm not sure. Did fry clutches in my other TH400 and the car wouldn't move no matter what you tried. The fluid had a very burnt smell to it. Come to think of it, the suburban my parents used to have puked out a lot of fluid going up a long steep hill when it got too hot. Have you checked the fluid level since you got it home?

 

does it have too much fluid in it? overfilling it will cause overheating and puking fluid as well.

one possibility is that the front pump is bad.

 

i do have a little to much fluid in it, but when i start it up it goes into drive and reverse just fine, but after a bit of warmup time it doesnt go into drive anymore but reverse still works great.
i also tried to bleed some fluid off by taking one of the lines off of the cooler but all i got out of er is a slow trickle, not the gush that im used to from a chevy. that part is leading me to believe the pump is bad, but the fact that it works for awhile throws me off. every other tranny that quit on me just up and quit, none of this halfway BS. mabye i should check the filter

 

when its cold the pump is tight enough to make it work, when it gets hot the parts expand and the pump no longer works, you should have more than a trickle coming out of the cooler line, if i remember correctly cooler pressure is around 15 psi.

 

are all th350 pumps the same? i have a few other th350s around but non with the short shaft this one has, so i was thinkin i could just swap out pumps so i dint have to get a different drive shaft.

yea i've seen GM trannys blast fluid all the way across the shop when a line come disconected, its a funny sight when a coworker is caught in the blast and lets out a blood curdling scream

 

all of the non lock-up pumps are interchangable. if the donor pump has a washer, you need to use it. if the donor pump has a bearing, you need to use it.

 

im pretty sure they are all lockup trannys, but i will have to look to make sure. are there rebuild kits available for just the pump or are their only total tranny kits? would folks here like to see pics posted on here of the rebuild? or is that not allowed?

 

as far as the lock-up pumps go, there are two different ones and aren't interchangable.

you can buy pump gears and gaskets seperate from any transmission parts place but it is usually better to buy a remanufactured pump since they require machine work almost all of the time. th350 pumps are alot different in design than a th700 is.

 

You need to look at the forward clutch pack(second drum in after the pump). The clutches will most likely be a lovely shade of black. Check the sealing rings on the pump, more specifically, the top two(farthest from the pump body)for wear. If the pump body where the seal rings set is rough(on the outside, not underneath) that is probably why the forward clutch pack failed. If the seal rings are teflon instead of steel, make sure the ends of the fit together they should look like a backslash(\\) not this way(\/). Also, look down inside forward drum where the seal rings ride(where the input shaft meets the drum) and check for grooves from the seal rings wearing on the drum. If you can feel them with your fingernail or pocket screw driver, the drum is toast. The other possibility is when the piston on the forward clutch drum was installed, one of the lip seals was torn or cut. Let me know if you have questions..............

Billy