My trans does not like to shift into 2nd when accelerating hard,at wide open throttle. It will hit the rev limiter and the tach bounces a couple of times before it shifts.

How abnormal is this?

 

Extremely!

 

Any ideas or suggestions?

 

Don, three things first:
1.I am assuming you have an automatic tranny, correct?
2. Are youthrowing any DTC's?
3. In your signature, please give some information on your truck. It makes offering help a lot easier and faster. For example, take a look at my signature on my posts.

 

'03 ZR2 with 4.3 and 4L60E.

Everything else seems fine and its not throwing any codes.

I'm wondering if a speed sensor or throttle position sensor would cause this?

 

If you haven't had your vehicle scanned for codes, now would be the time to do so. However, this may not be something that can be done for free at your local autozone or advanced auto, but try there first and let us know. If they come up empty, then it may be time to take it to a trans shop and let them have a look at it.

 

I've been to a good transmission shop. They changed the fluid and filter and inspected the pan for debris. They said that from what they can tell the transmission is perfectly fine. They also checked for codes and came up empty. They were the ones who suggestedthe possibility of a bad throttle position sensor. Everyone I've talked to has said that a bad TPS would throw a code, though.

I don't know what to do next.

On a side note, the problem is more apparent when engaged in 4X4, where it does it almost all the time. In 2wd it only does it occasionally.

 

Nobody else has had any shifting problems similar to this?

 

I'm not sure that a faulty TPS would cause this, but it may be worth a try. You can test your TPS with a regular volt meter, but you'll have to probe the wires through the insulation so have some electrical tape ready to seal the holes back up. I posted about this in a few other threads. CLICK HERE for some information regarding testing your TPS sensor.

The MAF sensor being dirty can also cause various driveability concerns. Wouldn't hurt to clean it either.

 

this is exactly what mine does change out your crankshaft positioning senser if your hasn't thrown a code it will soon my was doing it for a while till it started throwing a code i changed mine and it doesn't do it anymore.