vx is shifting badly

[stu]

I bought a vx in november of last year and love the vehicle but I changed the oil in it last week and for some reason, right after that it started to shift very rough and seems to be sliping in gears. Does anybody have any good ideas as to what this might be?

[mbeach]

Did you change the oil yourself, or did you take it in to have it done?

If you took it in, there is a very real possibility that you are now low on transmission fluid. The 4L30E transmission is a sealed unit -there is no dipstick to check the fluid level. On the bottom of the pan, there are two plugs -the lower for drainage, and the higher for fill/check.
It is possible that the pit jockey either pulled the wrong plug to check the level, or they let fluid out when checking the level from the top plug (easy to do when the engine is running).

The transmission is a decent unit, it just requires above average attention to detail on the part of the service department. It is not Isuzu specific, as it's a GM model, and found in many vehicles.
I'd recommend that you take it in for a transmission service -somewhere that knows for certain how to check and fill a sealed transmission.

[Ldub]

mbeach,
Would you outline the proper procedure for checking the tranny fluid level?, I was under the impression that it was checked by removing the top plug while idling, in park, with the trans. @ warm (operating) temp.
I'm pretty sure I've seen this info. posted before, but thought checking again wouldn't hurt.
Thanks, Ldub

[mbeach]

Joe Black does the best job of explaining the service here:
http://www.antiquecaterpillar.org/vx...l/4L30E_01.asp

The service CD has another procedure for checking fluid, and it's not likely to be known by the average Jiffy mechanic.

1.) Park vehicle on level ground, apply parking brake.
2.) Check fluid level with engine running at idle
NOTE: Ensure transmission fluid temperature is BELOW 86*F
3.) shift through all gear ranges
4.) shift into park
5.) idle for 3 minutes, then open the overfill screw(the top one).
6.) add fluid until it flows out of the opening
7.) let engine idle until a fluid temp. between 90*F and 135*F is reached, THEN close the overfill screw. Fluid temp is checked with a scan tool.
8.) torque screw to 28 lb ft.

Minimum fluid level @135*F
Maximum fluid level @ 90*F

DO NOT:
-open the overfill screw with the engine stopped
-immediately after driving at sustained highway speeds
-in city traffic, during hot weather
The vehicle should be allowed to "cool" for 30 minutes if any of these conditions are present.

I should have made my earlier post clearer -it's easy to assume that the fluid level is full when then engine is off. Most people (myself included) are not too keen on sticking their finger into a fill hole when the engine is running.
If the engine is hot, they could've figured that it was low on fluid then added some to bring the level up -overfilling it. This would cause driveability issues as well.

[Ldub]

Thanks,
I was thinking I'd been doing it completely wrong...at least I was in the ballpark. Now, to fine-tune.

[IndianaVX]

so is the "sticking finger in hole" operation to check level, temperature, or type of metal certain round body parts are made of ?? I would assume that full would mean that as you fill, fluid would run out, and then stop when it can no longer "run" over the lowest edge of the hole,now its full,- correct??? also, i dont have a scan tool, so will my moms candy thermometer, (or equivilant,) work...not sticking the thermometer in there, sticking the turkey baster in there (or syphon) to get some fluid out,put fluid in jar, and check temp. or can you drive a half mile to get to check temp, or will tran fluid warm up along with engine temp. i have to change tran fluid, and would like to do it myself, in two changes. so i want to be doing this right. have read the other post on this also.
thanks in advance
david