Auto line pressure- where and how do I check it?

[dpuckett]

Mom's auto has gotten real sloppy in the last 2 years, at least IMO. She says it shifts smooth, there is nothing wrong. I say having to push the go-pedal halfway to the floor to get it going indicates a problem somewhere. And the transmission shop in town says it is ok. I think they are looking at a $2500 rebuild. Boy will they be surprised when I tow the pickup to a shop that will do an aftermarket install, i. e. DTT or ATS, et al.



ANyway, I'm not too up to speed on the autos, and I know that line pressure will affect TC performance, which in turn will affect overall performance, esp MPGs. I also know from my readings here that there is a way to check and adjust the line pressure, contrary to what the transmission shop says. THey probably fill the Getrags to the stock level, too , but I wont go on too big a shop bash this time round.



So, how do I check the line pressure? Do I do it hot, cold, luke warm? How do I adjust it? Can my non-OEM oil pressure gauge work on it? Or do I need some $75 set up from the SnapOn guy? Coming up with fittings is not an issue. I'll do a search if I come across a faster net connection; I live in the sticks, and do well to get 24K dialup connection.



Daniel

 

[hdm48]

I could try to tell you where the test port is, but, I would recomend you stop by a transmission shop and have them show you. I t will only take a second.

Also, I've tried to discribe where and how to adjust line pressure to people on the phone and PMs. It don't work so pretty good. So, while you're at the transmission shop, have them show you where the adjuster is on the valvebody.

Now regarding your moms truck. I'm thinking it is a torqueconverter problem. Sure, line pressure can play a part, but if you have to use half throttle just to get it to move, that's a converter problem. When you do your line pressure test, you'll see that at half throttle you're up over 70psi and that is more than enough.

Have you tried to do a stall test? I would start there and move to the testing after.



Dave

 

[dpuckett]

Ok, maybe half throttle was a slight exaggeration, but it does seem to take a good deal more pedal than it did a short 70K ago. I'll try to find a shop that knows a 727 from an E4OD and see what they have to say. Might stop by the dealer and talk to one of their guys.

 

[y-knot]

You talk about adjusting line pressure in order to help your lame trany, but have you none any of the "normal" maintanance procedures? Dirty filters are also a cause of poor performance as are out of spec band adjustments. These are very easy to fix items that are covered in most all truck manuals. If these have been overlooked , start here. The band adjustment will take care of many items like slow performance and lazy take offs. Don't forget to use a quality transmission fluid to replace the old stuff, good luck.

 

[dpuckett]

y-knot,

Fluid and filter changes have been done every 20K or so; 12K when I was towing with it. I think I'll do the next one, before I leave town again. I'm getting awful tired of MO... ... .