Hi All,

I have a 1991 745 Wagon with 162K miles with automatic. Just last week I noticed that the transmission fluid had changed milky red in color. What should I do?

Last fall I made a change of the transmission fluid and the fluid was ruby red in color. I also changed the radiator fluid and changed the radiator cap to a new ‘green’ one. All this winter everything looked OK until this spring I took a long trip in the car and notice that it was leaking radiator fluid around the seals of the thermostat and around several of the radiator hoses. It was at that time I realized the system probably had to much pressure. I changed the radiator cap to a black one.

I came back from a trip last week and realized that the radiator fluid had changed a milky color. The transmission shifts fine. What should I do? Change the transmission fluid? Get a new radiator? Is the transmission cooler probably leaking fluid into the transmission lines? HELP!

Your help is greatly appreciated,

Mike

Or save some money and switch to an aftermarket tranny cooler. cut the lines coming from the radiator and loop them together so coolant won't leak out.

I would bet that you have a leak between the transmission cooler (in the right hand side of the radiator) and the cooling system. You should change your radiator, coolant, and the transmission fluid without delay.

The Ethylene Glycol in the antifreeze will eat the clutches and their adhesive backings in your automatic transmission. In a typical American built vehicle, the clutches usually have a catastrophic failure after about 2 weeks of being exposed to any significant amount of antifreeze. However, the Aisin Warner transmissions in our Volvos seem to be built to a significantly higher standard and there are brickboard members who have driven for as long as 6 months to almost a year before the clutches came apart after a similar event (they also didn't notice the presence of coolant as quick as you have).

I would strongly advise doing the following items as quickly as possible:
1. Replace the radiator and coolant. Use the official Volvo coolant if you can afford it since it contains no Phosphorous. Mix 50/50 with distilled water (never use tap water unless it's an emergency).
2. Flush the transmission. Ideally, take it to a transmission shop and have them remove the pan and attach an adapter over the filter/strainer that can supply clean fluid to the tranny while the car runs for a few minutes. You'll probably use about 10-20 quarts of fluid to get the antifreeze purged from the system, but this is a lot cheaper than installing a used transmission. If you have to do this at home, be prepared to spend a Saturday to pull the pan, clean it out, put the pan back on, and flush the system by detaching the transmission radiator return line. (then run the vehicle until 2 quarts are drained, refill, repeat, etc, etc)

Since you've noticed the problem early enough, there's a good chance your transmission will survive this event and go on to carry you another 100,000 miles or more. -but no guarantees. The sooner you can take car of this, the longer your transmission will last. The worst thing you can do right now is drive your car, or just let it sit. The clock is ticking.

God bless you and your transmission,
Fitz Fitzgerald.
--
'87 Blue 240 Wagon, 246k miles.
'88 Black 780, PRV-6, 145k miles.

Out of ignorance...why drop the pan. Wouldn't a flush in the FAQ do the same thing?
--
D.P. Mulvey in Central VA. 1991 744 NA, 150K Miles

Most automatic transmissions have a filter in them. -our rear wheel drive Volvos do not. We have a strainer, and it's not a terribly fine one either. There is a magnet in the pan, intended for collecting metal shavings and clutch material as the transmission wears down, but this is severly undersized for the job (and quickly becomes loaded to capacity). Needless to say, as the clutches and bearings wear down, a large amount of sediment begins to form and settle in the transmission pan. -you won't believe how much until you pull the one off your car and clean it out.

When you perform a tranny fluid flush on a RWD Volvo, the new incoming fluid breaks up a lot of sediment and it begins to get sucked up into the transmission through the "strainer." As durable as these Aisin Warner transmissions are, this not unlike running sand in your engine oil (with no oil filter). A lot of wear will occur very quickly and potentially lead to a catestrophic failure. If you order a tranny flush kit from IPD, IPD puts a printed paper in with the flush kits that informs you that they are exempt from liability if your transmission blows up or breaks down after you flush the fuild out. They are expecting you to be a responsible mechanic and clean the pan and magnet first, before you flush the fluid. Otherwise it's like changing your oil but not the oil filter.

I would strongly advise replacing the small 1" square magnet in your transmission pan with a larger 3" ring magnet from a General Motors T-125 (very common 3-speed automatic FWD transmission used during much of the 80s and early 90s). The GM magnet is much more suited to hold the extra shavings/material and doesn't become loaded before 30,000 miles. Filling the transmission with a fully synthetic ATF fluid (like Mobil 1 synthetic ATF, or Amsoil) will both greatly reduce tranny wear and tranny temperatures (less friction and better heat conduction). Average temperatures inside the transmission are somewhere between 190-210 degrees F, and by reducing the temp by 20 degrees you will effectively double the life of the clutches.

God bless,
Fitz Fitzgerald.
--
'87 Blue 240 Wagon, 246k miles.
'88 Black 780, PRV-6, 145k miles.

Thanks for the information. I am due for a tranny flush, and would have overlooked that key part of the service.

--
D.P. Mulvey in Central VA. 1991 744 NA, 150K Miles

You need, at least, a new radiator: it appears that the transmission fluid cooler is leaking pressurized coolant into the transmission fluid. You also appear to have an overpressure condition, so change the thermostat as well and continue watching this. While you are at it, you might change the heater water valve and all hoses since they are at the ends of their useful lives.