New Injection pump

[wvo]

Dr. Lee,

I recently had a new injection pump installed in my '82 6.2L suburban. Since I picked it up from the mechanic, the automatic transmission takes an extra 5 - 10 MPH to shift gears. For example it used to shift into second smoothly just under 20 MPH. Now it waits until higher revs and a speed of about 28 - 30 MPH. The shift is more of a jolt now. (Same for the shift into third) I noticed what I thought was a vacuum line going to the transmission from the pump. Could this repair have effected the transmission?

Thanks in advance,

todd

[bespander]

There is a component that modulates the shift points. If you have a Turbo 400 it is a vacuum actuated switch that must be adjusted. It is located on the passenger side of the IP and will have two vaccum hoses. First make sure you have good vacuum and the hoses are connected properly. The shift points can be adjusted by rotating the modulator around the throttle shaft, two set screws. I use trial and error, but you can have a spacer block machined and use a vacuum source and a gauge to set.

I don't know how the modulator works on a 700.

bill

[CleviteKid]

If your 'Burb is a C or K 10, is should have a 700R4 transmission. This is controlled by a TV (Throttle Valve, even though there is not a real "throttle" on a diesel) Valve that is controlled by a wire from the injection pump to the transmission. This was probably misadjusted after being reconnected to the new pump.

Take a look at the Bowtie Overdrives EXPLANATION OF THE TV for lots of information, and links (pun intended) to how to adjust the cable. Please get this done soon; you can burn up a 700R4 pretty quickly if the TV cable is out of adjustment.

Dr. Lee

[wvo]

Thanks alot, I appreciate it

[wvo]

Thanks Again,

Doctor I should have been more specific when I posted. I do have the vacuum line running from the injection pump to the transmission type setup. I read the article in the link you provided and it was very interesting. So I used Bill's advice. When I checked for vacuum I had very, very little. So picked up a new vacuum pump and installed it today, adjusted for shift point and it is shifting smoother than ever.

Happy again