96 Volvo 850, transmission slips, changed fluid, now works?!

[jsinatra]

I have a 1996 Volvo 850 with 160,000 miles. I've recently had to replace a number of things, including the radiator, starter, & fuel pump. Nothing major, but this issue is a little more serious. I just had the fuel pump replaced 3 weeks ago, don't know if that's relevant but thought i'd mention it. I was driving on the highway and just as it got up to 70mph I noticed it was running a lil rougher then normal at those speeds and not long after that the car "slipped" out of gear and I coasted off the highway. Couldn't get the car to get into any gear so i had it towed home. When i got home i ran it through all the gears and tried the "40-50 times fast through the gears" PNP test. After that the car would go in and out of drive and reverse, but would slip out and back in at times. I emptied the ATF fluid, it was dark brown, replaced it with the proper type of ATF fluid and some LUCAS additive. I figured all this was worth a shot. The car will now go into all the gears, and i've taken it around the block 3 days in a row now, just as a "test." This past time i drove around for 10 minutes, and reached speeds of over 50mph with no issues. Couple questions i guess....how long will this last? Temporary fix? Could it be the PNP switch? Is my transmission done? Should i replace the transmission filter now? This is my first post, thanks for your help.

[jblackburn]

The honest answer to your question? No telling. Generally these are very well-built transmissions.

I had issues with mine dropping out of 4th gear and into neutral somewhere between 2 years/40,000 miles ago. When I stepped on the gas again, it would just rev unless I pushed hard to the point it would smash into 3rd with a big clunk and work fine for the rest of the drive. If I dropped it into 3 or L manually, it would upshift back up into 4th with no problems again. I thought my transmission was done. I changed my fluid and it helped slightly, but it would still happen on hot days. I then stepped up to a synthetic transmission fluid, and haven't had a problem since with it - it's now at 183,something miles

[jsinatra]

thanks for your reply, and yeah that's kind of what i figured...there's really no telling. I drove it today about 20 miles, and had no issues and it actually appears to be shifting better then ever. Synthetic ATF? Hmmmm, should i give that a try at this point, even though things appear to be working at the moment? Thanks again for your time.

[thecheat]

I thought I had bad motor mounts from how my transmission was clunking into gears. Changed one gallon of fluid and it made a huge difference.My guess is that the fluid breaks down after years of heat and it loses it's viscosity.

[VolvoTurbo850]

Transmissions are the magic box which keeps us all guessing.

I have had a bunch of 850 / 70's and rarely have had tranny problems. Some have had over 500,000 kilometres/300,000 miles and they main seal might leak but they keep going.

On the other hand my 99 burned out at 146,000 klm or 90,000 miles on the previous owner before I purchased it. My ex Volvo tech told me the newer that tranny is the bigger chance you have of it failing.

I thought i got a special deal because i repaired the ABS unit because sometimes it causes tranny issues. I drove the car for 4 hours and it was smooth. THen when i thought i should go for a longer drive.. guess what.. slipping and not engaging!

SO I hope your problem is fixed, but do not plan any long trips until you know for a fact it is fixed, or is it just waiting to.. slip up!

[IzzyFink]

This is great for me to try! I recently bought a 96 850 and it's been slipping more and more lately. Only 3rd gear slips. Maybe I'll try changing out some ATF!

[scot850]

Strange thing. Most owners ignore this need to change the trans fluid. Apparently it is a fluid for the life of the car or until the trans fails!

Neil.