Transmission interchange

Is there any reason why a 98GTP transmission wouldn't install into a 99GTP and function properly?

The old beast is giving in and its time to address some major issues before I am forced to walk.

99GTP
195K

Both should be 4t65eHD's, if the final gear drive ratios are the same I see no reason why the swap shouldn't work. Why go from a 99 to 98 though? You should search for 99+ to avoid having problems again in the near future.

If it were me, I'd try and find an 02-03 because if I remember right GM redesigned the PCS system and soloniods.

What issue are you having with your 99 trans.

The reason I ask about a 98 is because I found a ZZP rebuilt trans that is a few hundred less than what they want. I figured at some point, I would like to get one anyways but this got pushed forward after I gave my truck a facelift this past Friday.

During slow acceleration or putting around town, 25-45mph, it has issues with shifting into 3rd/4th. It will shift up but it doesn't seem to have enough power or RPM to keep it going. This gives the feeling of lunging forward as it grabs the higher gear. No difference in feeling with a manual transmission when you are in too high of a gear and lugging along as you slowly gain speed. Things seem to work a little better if I wind it out a little further and then keep the RPM's around 1900-2000 or so.

I'd rather not pass up a deal if it would function properly and I can get a fair life out of it.

Thanks for your input.

[edit] It is noted that it has the 3.29 gear conversion.

so with the 3.29 gear conversion you will need to get the PCM flashed to support it.

Better wait and see what Bob or Rich say about interchangability before you order.

Have you had your current trans scanned by a tech 2 or GM extended DTC scanner to see if any codes are present?

I have not had it scanned to see if there any issues. I will be taking it in on Monday for a tie rod but after that, I will get an appointment to get it in to the shop fro scanning.

I called a local place (bob sumerel) inquiring about getting the car scanned. he didn't sound like he was all that sure that it could scan anything more than what I can get from my AutoTap deal. What is the typical cost of this to get done? He said that it would run about $40 and could do it whenever I showed up.

By the way, AutoTap scanner pulled these two codes:
1. P0742 - Torque converter clutch circuit stuck on
2. P1811 - Maximum adapt and long shift

In the past, the P1811 has been present. This is the first time that I have seen the P0742.

Maybe I am mistaken but I thought that AutoTap had enhanced code reading capabilities with an add-on. Is this true or incorrect? I checked the website and it appears that they have a new line but didn't really indicate to me that they offered any upgrade package for the ATU reader to pick up GM enhanced codes.

Hope this helps at least a little bit. If not, I'll have to warm up to the dealership idea.

Thanks,
Ted

Since the P1811 showed up, I'd assume you are able to scan extended GM codes with your autotap, so bringing it to a trans shop for scanning probably wouldn't reveal anything besides what you already know now.

You can review this thread concerning the P1181 DTC....

http://www.automotiveforums.com/vbulletin/showthread.php?t=920671

However your issue sounds different.

If it were me, I'd run some seafoam trans additive through there. Then drop the pan and change the fluid and filter within a week and clear the codes. If that doesn't solve it, my next course of action would be to add the above mentioned shift kit, remove the sidepan and change out the TCC solonoid and PCS solonoid.