Another transmission failure, '95 850 T5

Post by **rspi** » 27 Nov 2016, 15:07

The other day my auto transmission started bucking in first gear. Now I'm driving it pretty passively, especially when starting out.

I was planning to add a transmission cooler to my car this week but now I'm planning it's replacement. The stock setup, running through the radiator is designed to keep the fluid temp close to the coolant temp, heating it up quickly, then trying to maintain it near 200°.

The C70's have a cooler installed in the loop. Not sure how much that has helped keeping those transmissions alive.

Would it be better to just bypass the radiator or keep it in line? My initial thoughts were to pull it off the transmission to avoid radiator failure contamination and have it run cooler. But in the loop may be better to help it warm up quicker???

Post by **sleddriver** » 27 Nov 2016, 15:44

Really? So that's why they put all three coolers in one package? To ensure uniform fluid temps. Interesting.....guess it makes sense in a colder climate.

Don't have those conditions where I am. We have Summer and February.

Sorry to hear your xnsmsn is bucking. I guess they'll all go sooner or later. I've always been curious just how they work.

Post by **rspi** » 27 Nov 2016, 15:49

When I purchased the car it had a bad transmission, 188,000. I drove the car like that for almost 3,000 miles. Had. a used transmission put in and it's now at 334,000.

I have towed across the country in two directions and the past couple of years have had the car weighed down with tool and parts doing my helper tours. Not sour that it's going out, just wondering if a axillary cooler would help.

Post by **chrafael** » 27 Nov 2016, 16:33

Don't know how cold it gets by you. You might notice it taking longer to engage lockup from cold because that is temp controlled at about 90 degrees. As a point of reference, after a long, hot highway run in 100 degree heat my trans temp is about 150 degrees at most checked with a infrared thermometer at the bottom of the case.

Post by **JimBee** » 27 Nov 2016, 17:42

Helpful info about heating the trans fluid, I hadn't thought about that, though I have some concern about tank-breach and getting oil in the coolant. On a trip that would be especially bad. My '96 850 probably has around 200k miles. It runs well. Over two years I did several drain and fills b/c the fluid kept coming out brown/blackish. It's pretty clear now, though a little over the full line. Shifts great.

I would like to take it cross country but wonder if I should put in a new radiator before setting out. Thoughts?

rspi: precopster posted a couple of tutorials on AT's, one of them was a complete disassembly with pictures. If a guy has some time for the work bench it might be fun to pull apart one of these transmissions and try to rebuild it. What are the vulnerable parts that wear mechanically? solenoids? clutches? I think he (or others on that post) said the solenoids are cheap and with the tranny out probably simple to change. Clutch disks? Can you even get them? If so, would the completed handiwork be a "new" transmission?