Transmission Identification Question

pontiac
bonneville
transmissions

#1

My daughter’s 1987 Pontiac Bonneville (appx 68,000 original miles, 3.8 liter V6 engine) has decided it doesn’t want to shift into reverse or any forward gears once it warms up (running engine 15 minutes).



I guess I have a couple questions:



1) What are the chances of the problem being something treatable while the trans is on the car? (fluid level looks good, fluid quality is good – it is red, does not smell burnt at all.)



2) I need help identifying the exact model of tansmission. I know thse cars usually have the 4T60 (th440), but I’d like to be sure. I wrote doen the contents o the trans ID tage, and they re as follows:



In a column along the left side of the label are the characters:



617FBHWL637



Stamped into the ID tag are the numbers:



190 38 05





Printe on the bottom of the trans oil pan is:



HYDRAMATIC DIV OF GM



Pan has 19 bolts



Nothing is printed on the valve body cover.



Can anyone confirm the ID of the trans?



Thanks.




#2

If the pan is square with a missing corner it is a turbo 350 trans. If the pan is widefrom left to right and narrow from front to back it is a turbo 400.


#3

I have an 86 chevy truck with a 700r tranny and it lost reverse. It was a TSB for the 700r. I had to have it rebuilt.


#4

Thx guys – some research has revealed that what she has in this car is the Turbohydramatic 440-T4, otherwise known a the 4T60 (not the 4T60E, that hit the market about 4 years later than the 1987 model year). It is weird that even though this trans is old years-wise it has decided to let go at only 68,000 miles.

The dipstick shows the trans to be overfilled. This is weird, because the level has always been fine and no one has ever added any trans fluid since she owned the car. Is this a possible symptom?


#5

It is a 440-T4 Mileage has nothing to do with it. Its 22 years old. Piston seals are old and worn out. (Hardened)

transman


#6

Thanks transman, you da man.


#7

OK, if the transmission is overfilled and still has a modulator valve, just remove it and the excess fluid will come out in a little bit of a hurry. The extra fluid will keep the transmission from upshifting to second sometimes. The full level is just under the hole for the modulator.

Not going in any gear is usually something that requires work (especially when the transmission is warmed up) but there is no harm in removing the excess fluid and giving it a try.


#8

It isn’t overfilled. When the pump is failing the fluid remains in the pan at or near the level it would be with the engine off.