Synthetic or not?

[vinceseg]

Hi everyone,

Just picked up a 05 Tahoe with 63K on the 5.3 (not FF) and was wondering what everyone is running in their engines. Synthetic or not? I'm not going to be driving this vehicle all that much either, and occasionally may put a boat on back, up to 4K#.

Is it worth it to go with a Amsoil, or a different synthetic?

Thanks,

Vince

 

[ma87k5]

Hello,
Well in my experience. Full synthetic keeps the inside of your engine cleaner. Little better fuel mileage (might not notice), takes longer to break down. More miles to next oil change. I've been using full synthetic for over ten years, and I have switched from reg oil to syn oil and back to reg oil and then back to syn oil and had no problems with the changes. No leaks. I just did a headgasket on a 5.7 tahoe and he used reg oil only. He did the 3k oil changes and the intake and head were caked with oil build up. He has around 178k miles on it. He now uses synthetic oil. I did a head gasket on my 5.7 tahoe with 122k miles and it was clean as a whistle. Both intake gaskets were the plastic junk ones. So my sugestion would to go to full synthetic oil and never look back. I aslo noticed the difference between mobile one oil and a cheaper synthetic oil. Nothing. Besides price. But do buy a good filter. Those you get what you pay for. Synthetic you can run 5k-7k miles without a problem between oil changes. I am no expert, and others will say that what I said is bull but this is what I have seen. Not heard from others. Wow this is the most I have ever wrote for a reply, and I am sorry for that.

 

[clkelley]

Yes, I would go with Amsoil if you want to use synthetics and save money over time. With Amsoil you can extend your drain intervals further than with Mobile 1 or any other for that matter, and that is warranteed/guaranteed by Amsoil.

Benefits? Better fuel economy, a cleaner engine on the inside, better wear protection, better cold flow protection, less thermal break down, etc etc etc.

 

[clkelley]

Let me know if I can help you with obtaining information about Amsoil products and pricing.

 

[vinceseg]

Thanks for all the information.

 

[TomC65]

Any thoughts on synthetic transmission fluid? My 05 Tahoe has the 2-3 shift clunk and was thinking of changing to synthetic.

 

[clkelley]

Synthetic transmission fluid is a great choice, as long as you don't already have issues. When you say "clunk", fill me in a little more there. Does it slip or slap? When does it primarily do this, etc.

 

[TomC65]

Clunk or slap... Not really sure. Never slips. Sounds like a muted clunk and only on the 2-3 up or down shift. I assume it's related to bulletin #05-07-30-012 (May 9, 2005) which says a PCM calibration may reduce the 2-3 shift clunk for some 05 models. Other posters said synthetic fluid might help.

 

[clkelley]

Have you had the transmission control module reflashed by a dealer? I would do that first or at the same time as changing your tranny fluid to full synthetic fluid. Yes to your question, the overall quality of the additives used in synthetic tranny fluid ensure better protection for vital components, etc. But I would definitely look into the reflash in combination with the fluid change. You can use the link below to check out what is recommended by Amsoil for your tranny. If you decide you would like to order Amsoil tranny fluid let me know first and I'll save you money over the pricing online.

http://www.amsoil.com/mygarage/vehiclelookup.aspx?zo=1678239

 

[TomC65]

Haven't taken it to the dealer yet. Only owned it 2 weeks. Looks like ATLQT is the best for my truck. I think I'd need enough to do 2 or 3 changes a few days apart to really get a good concentration of the synthetic in there. If I'm correct, only 5 or 6 qts will drain out with the rest staying in the torque converter. Then I'd take it to the dealer for the re-flash. I wonder if the professional service guys have a way to fully drain the transmission? Either way I'd be happy to support a Supporting Vendor. How do I order from you?

 

[clkelley]

Yes, you can order the ATL by the quart if you like to make it easier to pour into the tranny, but changing the fluid is actually not that hard to do yourself. Drain the pan keeping up with how much fluid comes out, remove the pan and replace the old filter with a new one then after reinstalling the pan put fresh fluid back into the tranny in proportion to the amount that came out.

Then disconnect the return line from the cooler AT the tranny and attached a rubber hose to it with a clamp. While you/or a buddy stay under the truck to allow the fluid to drain into your choice of recepticle, you/ or a buddy start the truck and cycle the tranny through the gears to get the fluid flowing. Drain the fluid in such a way as to keep up with the amount coming out. When you have drained as much as you added turn the truck off. Refill the tranny and repeat. Repeat this cycle until you have replaced the initial fill amount of the tranny.

It can prove to be kind of messy so have plenty of rags, etc on hand but doing it this way uses the normal flow of the transmission to replace the fluid all the way through without missing anything or harming it in any way.

 

[dogboss]

CLKELLEY
I was debating on doing the transmission filter and change myself. If I mix a new synthetic, say Amsoil, with the conventional fluid in the transmission- how will this affect things internally if you do not cycle through the fluid change as you have described.

I have an 04 tahoe lt. It has the stock transcooler on it.

 

[clkelley]

Mixing synthetic with the old fluid will not be a problem in most cases, as long as you just drain it and refill it. However, one of the biggest reasons for performing a full flush while draining through the cooler return line is to ensure that the old contaminants that are in the cooler itself get drained out with the old fluid. Like the radiator, the tranny fluid cooler holds old junk that the fluid carries past the filter at times and over time this build up can cause issues. But most tranny fluids are fully compatible with conventional fluids. Just make sure that it has the correct classification such as DEX II, IV, VI, etc. as recommended by your owners manual.

 

[scottvan]

I just put 6 quarts of Mobil1 in my 04, I think I'll try Amsoil next time. Thanks for the tip.

 

[clkelley]

I just put 6 quarts of Mobil1 in my 04, I think I'll try Amsoil next time. Thanks for the tip.

When anyone is ready to try Amsoil, make sure to let me know so that I can save you some coin and time...

 

[dogboss]

How much for a case of transmission fluid. 04 Tahoe?

 

[clkelley]

Hey dogboss, sorry for the delay, I have been slammed around here. To provide a proper quote, send me a private message with your zip code. I will also need to know the engine size in your Tahoe and whether it is two or four wheel drive. If you provide the VIN# I can find the vehicle information I need to make sure I quote the appropriate product and quantity.

However, as for quoting pricing in open forum, Amsoil has strict rules about doing that so I cannot provide pricing information in a post.