LT77 Five Speed

apexhunter · July 26, 2012, 06:07:26 PM

Hello to All,

I am getting closer to posting my car on the Photo Galleries .... but in the meantime I would like to get a confirmation from some of the more experienced members. I bought a finished 79 MGB V8 from a fellow in Calif .... have put about a couple of thousand miles on it....now trying to figure how to best service the car. It has a 4.2 Rover with an LT77 five speed ....S10 rear.

I am trying to trace an oil or trans fluid leak ..... thought I would start with checking the trans fluid level. The serial number on the trans... 19A087194C ...... I was hoping there was a D suffix in there as I know that is a bit stronger gear box .....but could anyone tell me the year of the box and what it came out of?

With the car on jack stands and with me laying underneath looking toward the rear of the car - I see a large ( drain plug?) on the left or passenger side of the box. On the right or driver's side I think is the level plug? .... it is a bit higher up then the drain plug ..... Is my assessment right?

I believe that the best trans fluid for these is something called GM syncromesh? can anyone give me a part number and how much I will need? Is this stuff at a GM dealership? Also what is the best method/container to use in order to fill with trans fluid?

Thanking All in Advance .... this is a great site and has propelled me toward the Dark Side after many years of trying to extract HP from that cast iron lump!!!

Alan
Boston Mass.
Cell - 617-599-9926

rficalora · July 26, 2012, 10:15:25 PM

I have a T5 and am not familiar with the LT77's so can't help with most of the questions. There may be a better way, but to fill the T5 I put the lid from a gear oil bottle on the trans fluid bottle because it had a nipple on it. I then used some clear tubing that was a snug fit on the nipple. You have to get the bottle higher than the fill hole and using the tubing made that easier.

rkas3882 · July 27, 2012, 02:06:41 PM

Hey Alan, you are correct, those are the fill and drain plugs and the lt77 should take just over 2 quarts I believe. The transmission has an oil pump inside and some guys racing with that transmission jack the car on its side and put 3 quarts in just in case the oil pump fails, thats what ive done on my conversion and no ill effects. You can use redline MTL90 or if you go to autozone they have castrol synchromesh on the shelf.
Randy

apexhunter · July 27, 2012, 07:39:39 PM

Hey Rob and Randy,

I much appreciate the response and the help. I bet Harbor Freight would have a cheap pump canister type of deal - cause there is not much room in that trans tunnel to get much height above the level fill ..... would be nice to just fill it with a feed/pressure of sorts ........ I now feel the need to purchase a nice creeper board to scurry around the Jack stands ...I keep buying bigger floor jacks ....MGB V8 ownership ... It has been great fun tho with this British/American hot rod!!!!

Have read a fair amount on the web on gear oil for the LT77 and like Randy believe there could be a number of those synthetics that will work and seems like the makers sell to other label products but its really the same gear oil. I also have to use more search options on this site for info. gathering - most likely much of what am asking is well documented in the history of this great conversion of MGB's ..... most likely go with the Redline product.

Alan Van Reed
Boston MA

rficalora · July 28, 2012, 12:33:34 PM

No room is where the clear hose comes in. You can get your transfer fluid container higher than the tranny either along side it or back where it narrows at the tail housing. Runtje hose from the bottle to the fill hole.

apexhunter · July 28, 2012, 03:58:21 PM

Rob,

Will give it a go .....have Redline arriving via mail from the source itself!

Alan

MGBV8 · July 28, 2012, 05:00:49 PM

I use a long clear hose attached to a funnel & run it from the engine compartment down beside the bellhousing. I jack up the right side of the car & add as much as it will hold.

apexhunter · July 28, 2012, 06:05:10 PM

Carl,

We may have a winner!!! Would save the ten bucks I would give to Harbour Freight for their gear pump!! and you are the second person advising me to fill with out worry of overfilling. In effect - insurance against pump failure I suppose.

MGBV8 · July 28, 2012, 10:15:54 PM

I think Glenn Towery adds an extra quart by filling from the top (removes the shifter). He had a pump go bad, but made it back home on a trip because of the extra fluid. That fluid pump is the reason I decided on a T-5. Whoever heard of a fluid pump on a manual tranny..... not me. Something else to go bad.

Simon Austin · August 02, 2012, 03:20:34 PM

I've got the LT77 in my Rover conversion as well as the RV8. Both are equally fun to change gearbox fluid. Some time ago (back when I owned stock MGB's), I bought a small pump which attaches to an electric drill. Added a length of clear tube to inlet/outlet ports and it'll empty a litre container in seconds.

Only way to go, IMHO. I used to fill with ATF fluid but have switched to Redline in the conversion. The RV8 isn't due for a change yet. I've noticed no significant difference between the ATF and the Redline.

The LT77 is a very "mechanical" gearbox in that shifts are not smooth-like-butter. It's particularly problematic from 1st to 2nd when cold but smoothes out somewhat when warmed up.