Eric D

Ok, I've searched the threads and have read where some say not to use synthetic oils in the 1997 through 2000 manuals. Taking a run to my local auto supply store, all they have is Dextron-VI. Reading the container's label it states it is good for use in GM vehicles. It also states it exceeds Dexron III. I ended up using Castrol brand Decron-VI. At $6.88 a quart it didn't seem to bad of a price compared to the others they had.

So, anyone have issues with using this Dexron-VI in place of Dextron III?

The trans shifts much better since the change. I was getting some gear crunching before the change. It is now gone and shifts like new again. I'm surprised it made this big if a difference.

lucky131969

I experienced the same positive results with good old Dexron III. Changed at 70K

Eric D

Yeah, I believe just the oil change gave the results, not necessarily brand or III versus VI. What I would like to understand is what happens to the old oil that makes this big of a difference? It’s as if new synchronizers were installed. Mine has 52K on the clock.

Carcass

I ran Mobil 1 Synthetic in my 98 for about 6 months,till I started reading about the tranny problems it can possibly cause,and, with it in there,the car really didn't shift very well at all.(almost like the stuff was too "slippery" to let the syncros work)
So I decided to go with the recommendation on the fill plug on the trans,and went with good ol' cheap Dexron III,and It made all the diffrence in the world-now it shifts like a Vette is supposed to shift.

Best "Downgrade" I've ever done...

ragtopws6

I use GM part # 88861800 in all the trannies. Superceeds old Dexron III and made for manual T56 cars.

0HorsePowerAddicts

I use regular dextron III in all the M6's i do. Never had a problem with it.

99vetteran

I'm using a synthetic in mine.

GettnBetter

Let's hope there are no ill effects from Dextron IV in a 1997-2000 MN6

The most complete description of the problem I have found is http://www.flaglercountycorvetteclub...%20article.pdf .

I use Amsoil synthetic ATD.

99vetteran

I think I'll go back to the Dexron III tomorrow.

Eric D

GettnBetter, thanks for the link to Vic Natiello's article. Vic did a good job at covering the issues. I'm not sure I want to use my C5 as a test bed for Catrol Dextron VI. That's what I replaced my trans fluid with. This brings me to the big question, will I have problems down the road? There is no doubt in my mind that changing out the old trans fluid with fresh has greatly improved shifting. My fear now after reading Vic's article, will it be short lived?? Will Dextron VI cause problems later?

According to Vic's article, there are NO guarantees that buying a product labeled as meeting Dextron III spec's you are really getting Dextron III that would be equal to the original. General Motors did not renew Dexron III licenses!

I’ll try to get a better grip on the topic over the next few weeks and will start doing some research on the topic. That will include contacting Catrol directly to pose the question about blocking rings and what year Dexron III spec their Dextron VI is compatible with.

Checking their website, maybe I should have used “Castrol Heavy Duty Multi-Purpose ATF”. There website states “In response to General Motors decision not to renew Dexron III licenses, Castrol has introduced a new product, Castrol Heavy Duty Multi–Purpose ATF. This new product meets the Allison Transmission new replacement automatic transmission specification, TES–389, which reintroduces previously licensed Dexron III products back into the market. This product replaces the Castrol MP Dexron III/Mercon”.

I should have done more homework before changing my trans fluid.

Eric D

Which one? I need to do more homework on this before I change to something else again. How long have you been running with your current fluid?

C66 Racing

Note to all - would appreciate it if you used reference #1206638 if you link to the AMSOIL ATD in GettnBetter's thread above to ensure the sale is credited to the forum!

Eric,
Confirming most of what was covered above, you don't want to run a Dexron VI in your manual. I've pasted a GM document I pulled off the internet somewhere a year or two ago that shows GM's position on this.

As for your comment about synthetic not being okay in 97-00, the issue is the paper blocker rings in the early manuals. But, the term "synthetic" has not been defined by the API and Group III, IV and V lubricants can be labeled as synthetic based on a court case in front of the NAD between Castrol and Mobil 1. Short story is not all basestocks are the same and some, such as AMSOIL's Group IV PAO basestock, do not seem to harm the paper blocker rings. See the technical sticky thread at the top of the C5 tech section for more info on this.

Many forum members with early C5s are using this fluid with good results (same fluid I use in my 02 Z06 at the track):
AMSOIL Torque-Drive Synthetic Transmission Fluid (Product Code ATD1G)


Document ID# 1897292
Subject: Manual Transmission Fluid Usage In 2007 And Prior Manual Transmissions And Transfer Cases - keywords case fluid manual transmission transfer #PIP3836B - (02/05/2007)

Models:2007 and Prior Passenger Cars and Trucks
2007 and Prior HUMMER H2
2007 HUMMER H3
2007 and Prior Saturn Passenger Cars and Trucks

This PI is superseded to add a note under concerns. Please discard PIP3836A.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

Use of manual transmission fluid part number 88861800 U.S. (88861801 Canada) in place of Dexron III.

Important Note: If the vehicle owners manual lists Dexron VI as the recommended transmission, transaxle or transfer case fluid disregard any information supplied in this PI. Use eSI and or the vehicle owners manual to determine what type of fluid should be used prior to referencing the below information

Recommendation/Instructions:

Manual Transmission fluid part number 88861800 U.S. (88861801 Canada) is currently available through GMSPO. Current and past model vehicles listed above with either a manual transmission or transfer case that REQUIRE Dexron III should use the above listed manual transmission fluid. This fluid is a direct replacement for Dexron III in manual transmissions and transfer cases. DO NOT use Dexron VI in place of the manual transmission fluid in any manual transmissions or transfer cases as a failure may result.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

Eric D

Brad,

Thanks for pointing out the document #1897292 and if I order Amsoil ATD I’ll be sure to reference #1206638 to help out the forum credits.

I have a few questions if you don’t mind. Does AMSOIL back their product with any type of compatibility warranty? If they have a warranty what does it cover?

Thanks again!

jrmotorsports55

I've been using Redline D4 for a few years now with no problems in my 99.

Jason

Eric D

Can anyone point me at a thread or posting where someone has claimed trans failure for using DEXRON VI? I did a search, but really didn't find anything. I really don't want to be the beta tester!

GettnBetter

I've been running the Amsoil synthetic ATD for about 60k miles now. No problems. I bought the 1 gallon jug and it filled the whole tranny with a little to spare, I use the leftover in my nitro RC engines as an after-run oil lol

lucky131969

Honestly Eric, I think you have contacts at work that could provide the most factual info, as opposed to the subjective info on this forum.....I'm curious what the GM boys take is on this.....

GettnBetter

Subdiver posted the facts. GM recommends 88861800. There is another post on these forums with a scan of the actual document subdiver translated to text for us here.

GettnBetter

This ATF is known to destroy newer 2001 and up carbon blockers, within a week or two in fact. I haven't read anything about Redline and 1997-2000 paper blockers. Given your success it might be OK.

C66 Racing

Eric,
AMSOIL does have a Corporate Warranty, though they don't specifically use the word "compatibility" in it. But, if you look at para 3.b of the AMSOIL Limited Warranty - Lubricants that should address your concern. Please do note that there are requirements to file a claim in para 5 that are worth reading ahead of time. And finally, to confirm the term "proper application" in para 3.b, the AMSOIL Online Product Application Guide provides AMSOIL's Corporate recommendations for all cars dating back to 1980. If you click the red box in the center of the above link, then type 2000 into the box and click build list, then open the Corvette link and click on the 5.7L you'll see all of AMSOIL's recommendations for your car. The Torque Drive that I mentioned above is their primary recommendation for your manual tranny (and mine). That would confirm you used the "proper application" for this fluid.

AMSOIL Corporate Warranty