The last time I went threw my tranny I bought everything under the moon as far as upgrades go except for the pump. The guy that helped me, took a scotch brite pad on a digrinder and cleaned the scratches out of the area where the rotor and veins go. He told me it would be fine. The truck has been fine up until a few months ago. I am beginning to wonder if the forward clutch is releasing at stop lights, because I feel a slight thump when I take off. I also get a thump around 25-30 mph when I get back on the gas. Its not slipping at all and the fluid looks good. From a dead stop WOT shift it hits every gear good and firm.

I now know that the pump can wear out and need to be machined and resurfaced. My truck has 175 K on it, the pump is the original other than being taken apart cleaned and what the guy I mentioned above did to it.

I checked pressure and in P,N,D,OD,2,1 I had about 90 PSI. If I floored it in park it would shoot up to 220 PSI. Reverse seemed low at about 100 to 110 PSI. What do you think? I am pretty sure the boost valve was replaced when I did the trans the last time. Its the Transgo .490. It also has the transgo 4L60E-HD2 kit in it.

It also has

The beast Reaction shell
Double cage sprag
5 pinion Planetary
New reverse input drum, with wide band
Sonnax TCC valve upgrade in the valve body
The tourque convertor is a cheap Reman

What else could cause low preasure in reverse other than the boost valve?

 

I'm not sure what you're feeling...BUT...I can tell you that anyone who uses a scotchbrite pads on a pump has no buisness even being near a transmission.

You may want to check all your mounting bolts, u-joints, and rear lash.

Frank
CPT