If your transmission has a shift pressure vacum modulator, restricting (but not cutting off) the vacum will increase the shift pressure. Sooooooo, went to Lowes and bought a needle valve and spliced it in line. Closed the valve, then just cracked it open a hair. WHAT A DIFFERENCE! Nice, firm, noticable *****.

I did that myself with vacuum-rated needle valve some time ago, and got inconsistent results over time.

My suggestion is to buy an adjustable modulator and do it right. Not only for Performance, but for reliability. The adjustment on the modulators is much more precise and the results are consistent. It'* a 5-minute job to change one.

Note that this will ONLY work on 4T60'*. Not on 4T65'*.

speaking of the adjustable shift modulators.......where would be the best place to purchase one?

Advance Auto. Model, MD-28


From 95naSTA

Well don't try Advance, they only seem to carry the non adjustable OEM one. Maybe ricerzone?

Edit: ryan, that isn't adjustable, i got the same one

I have that exact same one and it is adjustable. Works great.

yup, im going to get one today or tommarow and put one in.

Last I heard, those are only about $20 or so. Well worth it over the cheap option of DIY for the peace of mind and greater adjustability.

Word to the wise, if you ever intend to install a TransGo shift kit in the future, you'll have to back that modulator adjustment off a bit. With the shift kit, Jet Chip, and adjustable modulater set on full firm, the 2nd gear shift is BRUTAL. Hard-part damaging brutal.

yea, i think it was around 12 bucks or something and makes the shifts much more enjoyable. I dont have mine tweaked too much because i dont want to ruin anything but i did firm them up some.

Firming it up can save wear and tear on clutches. Particularly the 2nd gear clutches on the 4T60.

But it does transmit more shock load to other hard parts. It'* a trade-off.

I'll be backing mine off all the way to run on slicks at the track. I don't need to be breaking axles or diffs.