I have a 6.5 99 GMC 3500, everything is pretty much stock. I have had some issues with it but for the most part it's been ok. I’ve replaced the entire braking system and the vacuum pump. I went for a drive the other day and the tranny went into Limp mode. :mad:

I did some checks on the net and found the tranny gets its power from the ignition switch which usually fails when an aftermarket remote starter or alarm is thrown in. I have an aftermarket alarm!

Took it to the garage, on the way the exhaust decided it had enough and took off!!! My buddy at the garage checked and all was good at the ignition end to the computer. The garage figured it may be the computer crapped out, it was put back together and sent to the tranny shop. They removed the main tranny plug and she’s good to go. :cool:

Now in my quest for knowledge I’ve learned the PMD likes to crap out due to heat and should be relocated. How do I know when its pouched??? The only thing the truck does is surges when it is in reverse for a split second. Does this mean it’s done???

I’m looking at getting a performance package seen as I still need an exhaust. SSDiesel has one for my truck which includes the 4" alum exhaust, Performance Induction kit, Dual Gauge kit (EGT Pyrometer kit, Dual gauge pillar pod and Boost Gauge), and 80hp ECM Upgrade. If the PMD needs to be done I will sort that out also with the extension kit)

Anyone have experience with these items, any suggestions on other items I should be looking at. Is this a good kit? I’m not looking at spending a ton of $$$ just want it to last!

Thanks for the input.

Doubt it's the PMD. What is the trans doing? Explain to us what it's doing or not doing. Does the engine run good? Will it run at higher rpm's? Any codes or SES light?

The tranny is running fine, it was an electrical issue that is fixed as far as I know now. There were multiple codes indicating tranny issues, bad solenoids etc... but they are all good.

Now in my travelles I read somewhere if the vehicle surges when going into reverse it could be a sign of a PMD going sour. This is the only issue that I have now other then the need for a new exhaust.

PMD symptoms are usually stalling and inability to start. There is no fuel at the injector. If you are still starting, then it may not be PMD. Cruise control failure sometimes can be a sign of failing PMD.

Surging is one of the sign of IP going bad but there will be SES on with specific IP code. But surging may be caused by something else also like transmission.
How old is your transmission fluid? Need to make sure that transmission is not causing the surging. For example, my camry was surging at one time going back and it was caused by low trans fluid level and there was delay on it getting into gear when I want to go forward.

Also check all electrical connections? batteries and grounds. If you have loose connection, it can rattle and caused surging.

My tranny fluid was changed 3 months ago so its all good, so maybe i'll check around for grounds loose/ tarnished etc. What do you thing about the SSDiesel package will it be a good investment or should i look elsewehre, I need an exhaust regardless.

So I got the package from SS Diesel it now runs like a top. The problem I had was with the company I had do the install D&W. They are crooks. They did an absolute hack job on everything they put on.
I've had to fix wiring bad grounds, clean up the install of the auto meters. The exhaust was hammered and looks horrible which cost me an extra 200 bucks. Originally I was quoted 450 and ended up paying 700.00. and they had the audacity to tell me they didn't charge me for all of the hours they worked on it. They kept the truck for 2 days! I'm not done with them yet, but again I'd suggest not going with them again.

I prefer to install stuff myself, or at least have friends help me. I don't like taking my truck to the shop... to many people do not know much about the 6.5s, but the lead customers that they do. I know your case isn't really "6.5 related" but same story about taking something to the shop and not getting it right the first time.

ya it really disappointed me I could have installed everything but the exhaust myself, I didn't have the time and needed the truck for a trip for Christmas so i figured their a big shop they should be professionals...boy I was wrong they jacked me and I still ended up having to fix the mess. Live and learn.

I have the same truck in Chevy version. I have been experiencing the split second surge for a couple of years now. I always thought it was fuel related due to it not being my primary vehicle. Now I have been experiencing stalling conditions and no more surge. PDM on order from SSDeisel. I hope it's the fix. My ip was replaced about 4 years ago under waranty.

If you buy PMD from SSD, please get an extension cable and put them outside the engine compartment. Otherwise, in a few month, you will have the same problem again. I know SSD said that it is ok to put on the intake but that location is worst than the IP stock location.

I have a 6.5 99 GMC 3500, everything is pretty much stock. I have had some issues with it but for the most part it's been ok. I’ve replaced the entire braking system and the vacuum pump. I went for a drive the other day and the tranny went into Limp mode. :mad:

I did some checks on the net and found the tranny gets its power from the ignition switch which usually fails when an aftermarket remote starter or alarm is thrown in. I have an aftermarket alarm!

Took it to the garage, on the way the exhaust decided it had enough and took off!!! My buddy at the garage checked and all was good at the ignition end to the computer. The garage figured it may be the computer crapped out, it was put back together and sent to the tranny shop. They removed the main tranny plug and she’s good to go. :cool:

Now in my quest for knowledge I’ve learned the PMD likes to crap out due to heat and should be relocated. How do I know when its pouched??? The only thing the truck does is surges when it is in reverse for a split second. Does this mean it’s done???

I’m looking at getting a performance package seen as I still need an exhaust. SSDiesel has one for my truck which includes the 4" alum exhaust, Performance Induction kit, Dual Gauge kit (EGT Pyrometer kit, Dual gauge pillar pod and Boost Gauge), and 80hp ECM Upgrade. If the PMD needs to be done I will sort that out also with the extension kit)

Anyone have experience with these items, any suggestions on other items I should be looking at. Is this a good kit? I’m not looking at spending a ton of $$$ just want it to last!

Thanks for the input.


Just out of curiosity, did you have a aftermarket pre-oiled air filter installed on your truck before your tranny went into limp mode....????

If you buy PMD from SSD, please get an extension cable and put them outside the engine compartment. Otherwise, in a few month, you will have the same problem again. I know SSD said that it is ok to put on the intake but that location is worst than the IP stock location.

I agree, installed my new Dtech PMD on my old FSD cooler block (that was previously installed on the intake manifold prior) into the cooling nostril in the bumper. Drilled 2 holes in the upper back lip of the bumper & ran the 6ft extension cable, easy installation only took me about 45 min & I am SLOW.

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