'05 G35 Transmission Flush - What method is your dealership using?

[Q451990]

So I took our G into the local dealership for some warranty issues and asked specifically for a transmission flush when I called. I also asked if the G has a transmission filter (screen) accessable by a pan drop and was told "no" - so I said fine... let's just do the flush. I even said something about "so you just hook it up to a machine and change the fluid?" and he said "right"

$175 later I get an invoice with 5 quarts of transmisison fluid, a bottle of some kind of conditioner, and about $97 in labor. When I asked, the service advisor told me that the dealership doesn't even have a flush machine anymore. Gave me some theory about new fluid cleaning varnish off of the transmission case and corrupting the new fluid, but thought that the real reason was that the machine "uses too much ATF" and that stuff is getting expensive.

So we left the car there and kept the loaner until the manager can call me. I told him I could (and would have) drained and refilled the pan at home had I known they wouldn't hook it up to a machine and get all 10-12 quarts (whatever the G holds) exchanged.

So are other dealerships only doing the pan dain and top off method? Is this something new for this series of transmissions?

Heath

[Q451990]

Another question... is there a filter or filter screen in the transmission? Or an external filter? I looked through the FSM and don't see any kind of filter.

From reading the FSM it looks like a full transmission flush is possible by pouring fluid into the gauge port (filler) at about the same rate as it comes out of the radiator return line with the engine idling. In other threads about older Q45s this method has been strongly discouraged due to the possibility of the rear planetaries being starved... is this transmission designed differently and therefore safe to do this? If so, I can do this in my garage with a funnel and a bucket!

Heath

[SteveTheTech]

I know at my dealer a trans flush is <$500 for the full twelve qts. of J-Matic and we use the &*^&^* flush machine which transfers the fluid without a significant drop in fluid level. I hate the product personally but the machine does work.

I have replaced several valve bodies in G (Not a problem, usually people abusing the AWD system) and there is really only a screen there and no replaceable filter. The magnet on the inside of the pan could be cleaned if you decide to drop it but that will still not get all the fluid out.

I personally do not like adding additives to the J-Matic cars. I don't care what the reps from the company say about their products working with the fluid it is not what the transmission was designed to use. That's just my opinion, though.

[maxnix]

I know at my dealer a trans flush is <$500 for the full twelve qts. of J-Matic and we use the &*^&^* flush machine

OK, so is it

1.) pneumatically powered

2.) internally mechanically powered

3.) externally powered by the transmission?

[SteveTheTech]

It's powered by the output pressure of the trans pump.

[Q451990]

Steve,

What do you think about the method outlined in the FSM - particularly in terms of starving the planetaries? I would think they wouldn't publish that method if it wasn't OK, but it still makes me nervous. I think I would have to have a bucket marked in 1 quart increments to make sure I was keeping up pouring the fresh fluid in.

Oh, and where is that filter screen? Is it accessable without tearing the transmission down? I didn't see it mentioned in the FSM.

As a side note, the dealership said that the Nissan side had a flush machine, but that the cost of the fluid would be about $200 plus labor, without offering any credit toward what they already did. They offered to just give the whole service to me free, but I decided that I would pay at least for the fluid and mystery additive... there is some benefit to what they did so I didn't feel right about taking a freebie - I wasn't really fishing for that.

Heath

[qship96]

Why not just do 3-4 drain/fills at home using the drain bolt on pan if you really want to replace 80-90% of the ATF?

[SteveTheTech]

Steve,

What do you think about the method outlined in the FSM - particularly in terms of starving the planetaries? I would think they wouldn't publish that method if it wasn't OK, but it still makes me nervous. I think I would have to have a bucket marked in 1 quart increments to make sure I was keeping up pouring the fresh fluid in.

Oh, and where is that filter screen? Is it accessable without tearing the transmission down? I didn't see it mentioned in the FSM.

Heath

I have read the service procedure outlines in the ESM and I have yet to try it. The fluid is expensive and it will make a huge mess. I assume that it will not starve the trans for too long but as I said I have yet to attempt it.

Why not just do 3-4 drain/fills at home using the drain bolt on pan if you really want to replace 80-90% of the ATF?

I prefer this method with some of the older units that have dark fluid or signs of wear on the transmission.

As for just draining and filling the trans if it were my car I would D&F at 30,000 intervals as it is cheaper and the fluid will usually last the 60k that it is recommended.

[maxnix]

I prefer this method with some of the older units that have dark fluid or signs of wear on the transmission.

As for just draining and filling the trans if it were my car I would D&F at 30,000 intervals as it is cheaper and the fluid will usually last the 60k that it is recommended.

Exactly why a mechanical exchange is better on old expired fluid and varnished interior. A chemical cleaning agent and pressure is necessary to expell all of the old fluid, detritus, and varnish in solution with the cleaner (chemical flush agent). Also why internal filter screen and O ring require changing.

Drain and refill always leaves over 60% contaminated ATF. If this method is so good, why not also apply it to brake fluid, coolant, PS, refrigerant, etc.?

The answer is obvious, even for the scarecrow. Time to be in Kansas and quit dreaming about Oz.

[SteveTheTech]

I agree and on my personal cars that is the proceedure I have used. There are instances where that is not the best idea though. A poorly maintained decade old car with original fluid and a slipping condition with excess clutch pack clearance will not benefit from mechanical purging. I have had a few that ran worse after the service.

Drain and fill is pretty common on coolant, ps (if the car is off and the rack is being replaced) but thats another thread. Refrigerant is sort of a drain and fill in some ways.

In the real world most people are more concerned about the cost of maintaince rather than the benefits of proper service.

[Q451990]

Steve,

Is the filter screen in the G35 easily accessible from the bottom with the pan removed?

Oh, and this is a little disconcerting, but I wonder if it's a response to too much aftermarket conditioners and varnish removers being used incorrectly? Their stance seems more based on potential cost objections by the consumer than anything else.

http://www.titantalk.com/forum...h.pdf

Heath