Troca de flu�do da transmiss�o autom�tica (CA)

Bom dia pessoal, hoje to meio inspirado e resolvi iniciar este t�pico porque o assunto j� esta h� muito tempo incomodando a dupla Tico e Teco que habita meu cr�nio.
Vamos come�ar pelas indica��es do Manual do Propriet�rio e da vareta de verifica��o do n�vel:

Notem que o manual indica o MOPAR ATF PLUS tipo 7176 e que o DexronII s� deve ser utilizado caso o outro n�o esteja dispon�vel. J� na vareta indica: MOPAR ATF PLUS tipo 7176 ou Dexron II.

Bem, vamos agora �s considera��es do Manual de Manuten��o:



Mais uma vez aparece o MOPAR ATF PLUS, s� que agora com o numeral "3", e ainda a terminologia tipo "7176". Notem agora que o Dexron II n�o � recomendado sob pena de ocorrer chiado na embreagem.

J� li muito por aqui e por l� que o Dexron III pode ser utilizado em substitui��o ao ATF PLUS. Ainda n�o estou convencido. Fiz algumas pesquisas e vou colocar nos pr�ximos post's. Os gringos inclusive dizem que a s�rie RE (no meu caso 42RE, por ser Laredo) das CA tem m� reputa��o e s�o sens�veis ao tipo de flu�do.

Me aguardem........

Imagens Anexadas

	P1070590.jpg (93,7 KB, 97 visualiza��es)
	fluido ca.jpg (61,4 KB, 92 visualiza��es)

Carllo, mais uma vez um excelente t�pico.

Obrigado Leo

J� fazendo uma complementa��o, entrei em contato com a revenda Divesa, em Curitiba, eles tem somente o ATF+4 que � o flu�do de tecnologia mais recente, a R$40,00/litro. Sabe que n�o achei caro.
A d�vida cruel � a seguinte, se vou trocar somente 3.8L de fluido, misturando com o fluido j� existente, que nem ELE sabe qual�, o que vai acontecer com a CA se o dono anterior colocou por exemplo um ATF Dexron II ou III que s�o minerais, misturados ao ATF+4 que � sint�tico. A� vem aquele papo de choque qu�mico e f... tudo. Na verdade nem � uma d�vida, porque isso ningu�m vai saber me responder, ou aqui algu�m tem bola de cristal!!
[]'s

Carllo, isso � mesmo um detalhe importante e bem lembrado.

Como � complicado remover todo o flu�do do CA, principalmente do conversor de torque, eu fiz o seguinte quando peguei a minha XJ:
Troquei o flu�do normalmente, depois de 10 mil km, removi o c�rter do CA, lavei ele (e tava sujo), troquei o filtro e coloquei �leo novo.
Depois de 15 mil Km fiz a mesma coisa.

Reduzindo o intervalo da troca vc elimina esse problema e depois de umas duas ou tr�s trocas n�o sobra mais nada l�, a� volta ao per�odo de troca normal. At� pq no que vai pagar pra uma troca especializada pra remover �leo do conversor, etc, � mais do que o pre�o do ATF, eu optei por isso, at� pq economizo umas quirelas e nesse per�odo t� sempre de �leo novo.

Abs.

Dando continuidade aos estudos relativos ao t�pico seguem algumas informa��es obtidas no site:

S� membros tem acesso aos links:
Chrysler automatic transmission fluids: 7176, ATF+3, ATF+4

ATF+4

GM Frazier wrote:

Group I base oils can have a mix of different hydrocarbon chains, with relatively little uniformity; these oils are the least refined. They are usually not used for autos.

Group II are the most common base oils in �dino juice,� with good performance in most areas except cold temperature viscosity.

Group III are called synthetic, and have high molecular uniformity and stability. Group III oil bases are used in most synthetic oils.

Group IV are chemically engineered stocks, arguably with the highest performance and longevity.
For the full story behind the development of ATF+4, please see SAE paper #982674. It is simply packed with interesting data about the development of ATF+4. Here are a few tidbits:
The initial development was done using Shell's XHVI base oil. Only much later were other Group III base oils approved. (Currently, SK in Korea and PetroCanada are the only additional approved base oil suppliers.) The use of Group III base oils is probably the leading cause for ATF+4 being a more expensive fluid than ATF+3 (which according to the paper uses a Group II base oil).
Lubrizol developed a new shear-stable viscosity index (VI) improver
specifically for ATF+4. The initial tests of this VI improver in the
MS9602 test fluids were so remarkable that Chrysler modified the then-current ATF+2 spec (MS7176D) to include it. Thus ATF+3 (MS7176E) fluid
was born; it remained the factory fill until the introduction of ATF+4.
In testing done during development of ATF+4, Chrysler noted the following viscosity loss from shearing for the following ATFs (20 hour KRL Shear Test):

Dexron III - 40% loss
Mercon V - 19% loss
Type 7176D - 32% loss
Type 7176E - 14% loss
Type 9602 - 10% loss

You can see what a significant impact the new viscosity improver had on ATF+3 when you compare the 7176D and 7176E numbers. From the standpoint of viscosity loss alone you can see why Dexron III should not be used in transmissions that require ATF+3 or ATF+4. In terms of other basic performance parameters, ATF+3 (7176E) comes the closest to ATF+4, with Ford�s Mercon V a close second. [Which doesn�t mean that Mercon is acceptable.]
The goal in developing ATF+4 was to create a fluid that would match the performance characteristics of the current fluid (Type 7176D), but would retain those characteristics for at least 100,000 miles. The paper specifically notes that the anti-shudder properties of ATF+3 are usually degraded enough by 30,000 miles to cause noticeable shudder.
Contrary to popular myth, one of the stated goals of Type 9602/ATF+4 fluids was that it would have the same frictional characteristics as ATF+3. The paper explicitly states that this was because new clutch materials would not be introduced for this fluid and it had to be backwards compatible with ATF+3. Graphs in the paper show that the friction coefficient of fresh ATF+3 and ATF+4 is essentially identical, but as the fluid ages ATF+4 retains the �as new� coefficient while ATF+3 degrades.

The paper noted that one alternative was to use synthetic Group IV base stock, which are even more expensive than the ATF+4 solution, which provided Group IV style performance from Group III stock. ATF+4 meets strict low-temperature, oxidation, and volatility performance requirements and relatively low cost � believe it or not.
Valvoline now makes an ATF+4 fluid.
ATF+3

ATF+3 is a friction-modified, high-quality transmission fluid similar to the current fluid in most respects; but it wears out more quickly and has less desirable cold viscosity (to simplify: is too thick when cold). ATF+3 can be approximated by Dexron plus an additive but this does not save much money and is not as desirable as using the correct fluid to begin with.
Dexron itself is the General Motors-specified fluid from far back in automotive history. While it was once the standard for all American autos, that time has long passed, with Ford settling on Mercon and Chrysler on ATF+3 (and now ATF+4); other manufacturers also require their own fluids.
Engine oil has been used as an automatic transmission fluid, again in the antiquity of automatic transmissions; it is still used in manual transmissions, but generally a single-grade oil is used.
Usage

You can use ATF+3 with all older Chrysler transmissions (except as noted below - some Jeeps). ATF+4 is another story. This is from a Chrysler engineer:

If there is a doubt about which grade of ATF to use, follow the owners manual recommendation. AFT+4 in certain specific tests was shown to be incompatible with certain seal material. This incompatibility may cause a premature failure depending on the duty cycle of the vehicle. The fluid will work as intended however, it may cause a seal failure.

Chrysler is not the only company to require a unique transmission fluid. Dexron has long since passed its prime, and modern transmissions require modern fluids, which more refined properties. Toyota, Ford, Nissan, and other major automakers also require unique fluids.
Additives

David Castater noted: �I used Lucas transmission additive on the recommendation of my local Kragen counterperson... What a mistake!!!! We started seeing shudder at 55+ mph. The dealership told us it was the torque converter dropping out of lockup and the tranny would fail and should be replaced ($3,000). This was a dealer purchased rebuilt transmission less than 4 years old! My local AAMCO manager changed the oil and filter, added a"friction modifier", and reprogrammed the computer. No problems since!!�
John C. Lai wrote that LubeGuard, used with Dexron by AAMCO, is not a good substitute for ATF+3, either: "...although Lubeguard claims on their website that their product will convert Dexron to become an ATF +3 (7176E) equivalent, they actually have no test data to back that up. In fact, their head engineer told me that the tests they did were conducted in the early 1990s with the first version of 7176, several years before ATF+3 was developed. So, they have no basis for their claims of ATF +3 equivalency.

Dessa p�gina, em resumo, entendo que o Dexron III n�o substitui o ATF+3, a n�o ser que seja adicionado um aditivo modificador de atrito.
Reparem ainda na lista de percentual de perda de viscosidade logo no inicio do texto, o ATF+4 perde 10% e o Dexron III perde 40%.

Mais um motivo pra pagar R$40 no litro do ATF+4.

Mas n�o paro por ai, aguardem............

Abra�os e bom feriado!!!

Amigos,
Diante do que foi exposto aqui por nosso amigo Carllo, qual a recomenda��o? Qual o �leo usar? Quais as experiencias que tiveram com os devidos tipos diferentes de �leo?

Um abra�o..

Bem Mattos, o correto, obviamente, � utilizar o flu�do recomendado pelo fabricante. Qualquer coisa diferente disso � decis�o/responsabilidade do propriet�rio.
Lei atentamente as informa��es nos sites especializados e tire suas pr�prias conclus�es. Minha opini�o � a seguinte: visto que na troca peri�dica s�o retirados 40% do flu�do, cerca de 3,8L, o que deve acontecer a cada 48.000km para uso normal e 19.000km para uso "pesado", o custo � relativamente baixo, cerca de R$160,00 para 4 litros de flu�do ATF+4. Considerando 12.000km/ano, uma troca a cada 4 anos, d� R$40,00/ano.
Em resumo, o custo do flu�do recomendado pelo fabricante � muito baixo comparado ao custo de reparo de um CA. Eu prefiro trocar o flu�do a cada 12.000km, ao custo de R$160,00/ano, a fazer um reparo no CA, o que deve custar mais de R$3.000,00.

Segue mais um link, agora da AlfaTrans, que tem muitas informa��es sobre CA:
S� membros tem acesso aos links:

[]'s

Continua............

Boa Carllo. J� vi muita gente recomendar o Dexron III, mas voc� fundamentou muito bem sua resposta. Vou ter que fazer um reparo na CA mesmo, deu um problema em uma v�lvula/solen�ide e o meca vai ter que mecher mesmo, mas como os caras que v�o consertar sacam muito de JEEP, eles devem usar o que manda o manual.

Um abra�o, e parab�ns pelo t�pico.