View Full Version : TR5/TR250 250 Diff drain plug ?

02-05-2010, 12:11 PM
Greetings all,,

After consulting my manual and viewing my diff I cannot locate
the drain, I have however found the fill

any thoughts?


02-05-2010, 12:28 PM
Scrub all the mud/grease off the lowest point of the bottom of the unit. Is it there?

02-05-2010, 12:29 PM
Hi Tony,

If your 250 is like my TR6, there is no drain for the differential. Most of the guys who are reconditioning their diffs have a drain hole tapped for them while the diff is out for that very reason. If you want to drain the fluid out, you have two options. Suction pump or remove the rear cover.

M. Pied Lourd

02-05-2010, 12:38 PM
My tr3a has no drain either. I have purchased the plug and plan on drilling and tapping it, seems stupid to pull the cover and drain every time.

02-05-2010, 12:55 PM
scrubbed and cleaned nada

Ahh no plug, now that make no sense

I have it on a lift for the day

how easy is the removal of the cover ??

02-05-2010, 01:17 PM
Not bad to remove, it should be similar to my TR4 and I simply had to push the brake line out of the way to get it off. Getting the cover back on and sealed so it didn't leak took adding a little liquid gasket. When I only used the paper gasket I had serious leakage.

02-05-2010, 01:29 PM
I used my MityVac to suction the lube out. It really doesn't take very long to empty.

02-05-2010, 01:40 PM
No brake line to remove on a 250...unlike the 4 (like my 3A) the brake line on the 250 runs above the diff as it is not a solid axle car. Easy enough to get the rear cap off but you may want to clean and renew the gasket (I have heard suggestions of doubling the gasket as well) or use some permatex or similar gasket maker.

Personally, I would try to just pump out whats in there and refill with Fresh GL4 unless you suspect you have some other issue with the diff.

M. Pied Lourd

02-05-2010, 05:58 PM
You can't remove the rear cover on an TR4A IRS/TR250/TR6 differential while it's installed in the car can you since the rear mounts are a part of that cover?

TR250/TR6 differential (https://www.zeni.net/trf/TR6-250GC/15.php?s_wt=1280&s_ht=800)

Should be easy to remove after you drop the differential though.


02-05-2010, 06:30 PM
Yes, agreed, you would need to drop the diff to get the casing off.


M. Pied Lourd

02-05-2010, 09:46 PM
Oh so pretty
well since I have to drop the diff guess I will do all of the seals and mounts and bolts and I have a bad feeling about this !!!

02-06-2010, 01:03 AM
Don't forget to add the drain plug!


I like to use magnetic, socket-head plugs:


02-06-2010, 11:57 AM
wont for get that

02-07-2010, 07:51 AM
Funny how they included the boss for the drain plug in the differential casing (as can be seen in Randall's photo) but they simply didn't go that last bit to drill and tap the drain hole!

When I had Quantummechanics rebuild the shims and washers in my diff last year I had him drill and tap the drain.


02-07-2010, 11:42 AM
I am just guessing here but it would make sense that the rear portion could have been sourced from different foundry than the forward casing
English engineering omission as I am very familiar with that senerio

02-07-2010, 12:02 PM
My guess would be that the engineer who designed the casting deliberately left a pad for a plug, then the decision was made later not to drill & tap it. Or maybe the decision was already made, and the pad was just in case the decision got changed.