200-4R Transmission Servicing and Drain Plug Installation
Devin C. Tornow
You Will Need
Trans Filter Service Kit AC, Fram, etc. - includes pan gasket, filter, and filter seal (seal ring)
Drain Plug kit B&M 80250 about $7.95 source: speed shop, Western Auto, Summit, Etc look at http://www.bmracing.com/catalog/racing/pages/tranprod4.html.
Gasket-Drain Plug GM # 1409 0908 (metal washer w/neoprene insert, best available, Buy a bag! about $1 wholesale) (replace the nylon washer B& M supplies) use for ENGINE drainplug also.
Magnet, Chip Collector GM #378 7240 (200-4R) or 866 5830 (700-4R) - may already be in your pan (there is even a round dimple or lines in the pan where it goes on some pans)
1/8" NPTF plug with an internal hex Avoids hanging down below the nut on the drain plug kit (these are difficult to find but not necessary - helps adds ground clearance)
1/2" Drill Bit You may want to pre drill with a smaller drill first
Metal File To get rid of burrs after you drill the hole
Loctite I prefer the permanent type stuff to avoid the plug kit from loosening up ever.
Cardboard Use to make a really large drain pan (read the instructions)
1 Garbage bag Large enough to put the cardboard drain pan.
1. Make a drain pan out of cardboard that is large enough to catch all the oil from your transmission and about 3" deep (you only need to catch about 4 quarts). Sorry I have never found a pan that is big enough to catch it all so I improvise.
2. Place the cardboard drain pan inside the plastic garbage bag and tape the open end of the bag in place so it does not slide around and the plastic will catch the oil. The bag is used to catch the oil and the cardboard give the pan shape. I think this is easy to understand, if not let me know. (When your done you drain, turn the bag inside out and throw the bag away (and card board if you don't want it)!
3. Raise the car and make sure it is supported and secure. 3500 lb. cars Hurt!
4. Place the homemade Pan under transmission and loosen bolts. The idea is to loosen the bolts so you drop one end of the pan first by tilting the pan. Try leaving one bolt in back or driveshaft end and two in the front corners of the pan. Loosen the rear bolt about 1/2 way and it should start to drain out the back (if it hasn't already). Loosen up the front two bolts and the pan should tilt down further draining the pan. Finish draining and remove transmission pan.
5. Clean the bolts, pan and magnet (if you have one already) thoroughly while you let the transmission drain as long as possible (more the better). During cleaning inspect the pan for metal. If you find a grayish metallic transmission film in the pan, a small amount is normal (depending on transmission history) as is some black / gray fuzz on the magnet. Metal chunks are not! (Seek a transmission expert if this is the case.)
6. Look at the transmission internals and determine your preferred place to install the plug. Sorry I don't have an exact place measured and preference may change between individuals. You just need to make sure it clears every thing, it is not that difficult to determine. JUST REMEMBER - make sure you have the pan oriented properly and your not looking at a mirror image and put it in the wrong place. MEASURE 3 TIMES, DRILL ONCE!
7. Drill the pan using a 1/2" Drill bit - you may want to pre drill with a smaller drill bit first then the 1/2" drill. Deburr the hole using a metal file to make sure you get a good seal and don't cut up the drain plug gasket. Clean the pan thoroughly.
8. Put the Magnet back in place (if you already had one) or put a new one in on the round dimple in the 200-4R or in the square lines on the 700-4R. Some pans may not have the impressions so you just need to make sure it is clear of internal parts and electrical parts in the trans.
9. Install the Drain Plug Adapter (like a hollow bolt) in the pan from the outside of the pan as follows:
- Drain Plug Adapter (like a hollow bolt)
- GM Drain Plug Gasket
- Transmission Pan
- Loctite threads on drain plug kit (one drop will do)
- Nut (short style) from Drain Plug Kit on inside of pan (allows maximum drain)
- tighten using two 3/4" wrenches - make sure not to overtighten
10. Install the plug in the Drain Plug adapter. Make sure you hold the drain plug adapter with a wrench when you install the plug to avoid twisting the adapter and damaging the gasket. Remember this when you service the transmission and take out the drain plug. Your pan is now ready to install but you need to replace the transmission filter.
11. Remove the transmission filter by pulling out on the transmission
12. DON'T FORGET. Remove the seal that goes around the filter tube that inserts into the trans. It usually get left in the transmission and will cause you big problems if you don't get it out. You can use some kind of a seal puller or hook ended pick to get it out. Be careful not to scratch the internal bore of the transmission where the filter is inserted.
13. Install the new seal on the new transmission filter and lubricate with transmission fluid so it slides in easily into the trans. Without it may get damaged. Install filter into the transmission and press in all the way.
14. Reinstall the transmission pan and gasket. Do not use silicone or RTV sealer on the gasket, it will damage the transmission if it gets in the fluid. Tighten the bolts to 10-13 ft * lb (14-18 N*m) in an even alternating torque sequence.
15. Refill with at least 3 quarts. Start engine, let it idle, and check the transmission fluid level and add fluid to get the level just within the two dimples below the "Add" and "Full" marks (the crosshatched area). Try to check the fluid on the same level surface each time you check it. Cycle the transmission shift lever the from park to reverse to drive to reverse to park a few times. This will help get the fluid through all circuits. Recheck and add fluid to get it within the two dimples while it is "Cool" (65-85 degrees F). The transmission fluid will expand as it heats up, "Warm" should get the fluid in the lower 1/2 of the area between "Add" & "Full" and Hot (190-200 degrees F) will get it in the upper 1/2 of the area between "Add" & "Full" marks. Test drive and warm the transmission and recheck. Recheck over the next few times you drive.
16. Smile! Now your done and you won't get quite as oil down next time you service your transmission.

Service Intervals: In normal driving I change mine more often than normal (10,000 miles w/ filter with a fluid swap each at 5,000 miles) and most people consider this extreme. I consider it cheap considering the cost of a rebuild even using Mobil 1 synthetic transmission fluid! I have had 2 transmissions go 151,000+ miles in regular driving without ever being repaired or a hint of trouble. You be your own judge if you drag race.

I know this seems really detailed but I believe in "Doing it Right" or not doing it at all!!!!!!!!!!!!!

Last updated: