Transmission fluid change on an 82 300D

[biobenz240d]

I will be changing the trans fluid on my 300D this week. I have been looking in to the K1 spring and the B2 piston upgrade, do I need it ? She shifts hard from 1-2 and quickly into 3rd if I take it easy, and an abrupt shift into 4th. This all pretty much diminishes quite a bit after it warms up. Since I will have the pan off and drain the torque converter and filter change , what else should I do while I'm in there?
I've read about using Mobil 1 synthetic fluid and also type F fluid. Many people I've talked to say use Mercon fluid. I'm open to all suggestions as I only want to remove the pan once.
I've made all adjustments to the Bowden cable , VCV and the modulator to tweak the trans. to where It feels good. Just want to eliminate the cold shift aspects. I will be changing out the VCV because it won't drop to 0 at WOT, it will only drop to about 4. I'll do this before the fluid change.
Btw she has 255k on her and no history of and major work on the trans or engine. So let me hear the wisdom of this forum.
Thanks in advance...
Has been running on B100 and a WVO conversion for 2 months .

[bodyart27]

I have a K1 kit (pretty cheap) ready to go and did a lot of research on the B2trying to get the right part numbers. After a while debating, I'm now taking the "if it ain't broke" stance and wait and see after talking to a transmission guru at a dealer in Dallas. Sometimes being over preventive could bite you.

I endorse Mobil 1 syth fluid. Definately didn't make my trans any worse. I did recently replace the two little flippers that reside in the black box on top of the valve cover that regulate vacuum based on throttle - that made the biggest difference in shift quality yet on my car (go the dieselgiant.com website for a pictorial on that one - pretty cheap part from dealer). Those little flippers do wear down after 200K miles!

As you have probably figured out from reading posts - correct vacuum seems to be everything on these transmissions.

Also, I'd keep an eye on transmission fluid level - I think that can be an issue as well. Make sure the car is REAL hot (15 minutes of driving - check after your normal commute) - car running, in N or P gear selection, and on level ground. Take multiple measurements until you are comfortble with what you are seeing (vibration makes fluid jump sometime on the dip stick).

[dieseldan44]

Originally Posted by biobenz240d

I will be changing the trans fluid on my 300D this week. I have been looking in to the K1 spring and the B2 piston upgrade, do I need it ? She shifts hard from 1-2 and quickly into 3rd if I take it easy, and an abrupt shift into 4th. This all pretty much diminishes quite a bit after it warms up. Since I will have the pan off and drain the torque converter and filter change , what else should I do while I'm in there?
I've read about using Mobil 1 synthetic fluid and also type F fluid. Many people I've talked to say use Mercon fluid. I'm open to all suggestions as I only want to remove the pan once.
I've made all adjustments to the Bowden cable , VCV and the modulator to tweak the trans. to where It feels good. Just want to eliminate the cold shift aspects. I will be changing out the VCV because it won't drop to 0 at WOT, it will only drop to about 4. I'll do this before the fluid change.
Btw she has 255k on her and no history of and major work on the trans or engine. So let me hear the wisdom of this forum.
Thanks in advance...
Has been running on B100 and a WVO conversion for 2 months .

In my experience so far with my 722.315 transmission I have found that small vacuum differences can cause the shift irregularity you are describing. Replacing the fluid and filter is a good thing, but I would keep working on the vacuum system before starting to replace anything else.

For example, your VCV sounds like it is flaky.

Also, Id reccomend setting your modulator using a gauge instead of by feel. It eliminates a variable. I did a DIY for it that has now been wiki-fied. You would need to set to 2.9 bar or about 50 psi, same as me.

I have heard, and maybe I heard wrong, that these older transmissions will shift a bit harder cold even when new. Thats just inherent to the system. The five or so 722.xxx transmissions I have driven all did this.

Good luck,
dd

[biobenz240d]

Changed the atf fluid and filter today. The car shifts a lot smoother , also put in a pint of Lucas transmission fix. I used regular dexron , mercon fluid . I wanted to use Mobil 1 synthetic , but will end up changing the fluid again in about 20K.