Welcome to our resource for MG Car Information.



TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR6 - Slow shifting OD

My overdrive (J-type) takes about two seconds to engage. Doesn't seem to vary with temperature. I was running Stay-lube 90 wt GL-4, but changed a few days ago to Redline MTL. Same behavior. It's shifted like this since I got the car on the road, and I keep putting the issue on the back burner. (If it's broke and it works, don't mess with it???) Just wondered if anyone else has seen this.

Thanks in advance.......Rod
Rod Nichols

Rod - J types must have periodic servicing.

The delay sound like an oil flow problem. Let's not think about the pump at this stage, but check the filters first.

Drop the rectangular plate off the bottom (6 bolts) and save your expensive MTL for another gearbox - it is not really suitable for wet clutch overdrives - (refer to the previous thread in the archives under "synthetic oil").

Remove and carefully clean both pressure (round)and suction (rectangular) filters.

New gasket required - do not use silicone. You can use gasket paper and make your own so long as it is the same thickness as original. Use Hylomar or similar spray gasket adhesive. Don't over tighten bolts on reassembly, tighten in such a way to minimise distortion of the base plate (as you would tighten a cylinder head).

Refill with Redline MT-90 (has 50% higher viscosity than MTL at 100C).

This should help solve the problem so long as it is not too serious.

Roger H

Rod, I agree with the previous post but I would check a couple of simple things first.

1) Does the solenoid engage firm and without delay. I'm not sure if it would engage at all on the hold circuit alone but it's worth checking.

2)Check the condition of the gearbox oil, if it looks clear and no metal burrs I would doubt that the filters are blocked, but you never know. The drain plug is magnetic and if it looks like a hedgehog you need to get the box and OD out and overhauled ASAP.

I had the same sympthoms with my A-type box. The oil contained a lot of metal as a result of a an earlier layshaft crash, I didn't catch it in time and it led to a replacement OD. :-(

Good Luck, Goran..
G Wennergrund

In my pursuit of The Holy better shifting OD, I finally looked at the J-type theory notes on the Buckeye site. The author claimed his shifted this way too. Before I tear into this with wrenches and drain pans, can any J-type OD owners tell me how theirs is shifting? TR6 owners with OD seem to be rare in Spud City......
Rod Nichols

Hate to spoil the spanner party but Two seconds for an OD to shift seems quite reasonable to me.
R. Algie

Rod - depends a bit as to how long two seconds is!!!

We've been metric here for decades and it's hard enough trying to communicate in imperial measure...;)

Mine snaps into place at .......(switch)....."one thousan..." By the time the second word is complete, it's engaged.

Just a word of caution though...please consider the content of the thread on synthetic oils...I'd suggest that a mineral oil would be better for the o/d than the syn you are using.

Roger H

Rod, My overdrive used to "snap" into action just as Roger's does with less than a second delay. However, last summer over 3000 miles of driving it slowed down--when I put the car away in October to start a complete engine rebuild it had reached the 2 second delay you speak of --I wasn't happy. Over the winter , I found a couple of things : 1. one of the overdrive wires was frayed at it's end with only one strand of wire left, the bullet fitting broke off in my hand. Ah-ha. So, I cleaned ,reinforced and replaced all the fittings/connections over the winter. 2. Also, I cleaned the filters that Roger mentioned, ( but they seemed really quite clean to start with - as per what Goran said ). 3. I also replaced all the o-rings in the solenoid. They "seemed" ok, but it's hard to say about o-rings.
I'll be starting the engine for the first time and driving in the next week , I'll post again with the results but I'm hoping to return to the quicker "snap". I have a pressure guage and will test if performance isn't improved.
David Johnston

A friend with an "A" overdrive in his car said a lot of the 'snap' was taken out of the J to keep from beating up the IRS. The TR3 his father drives shifts very hard, and he usually uses the clutch when shifting. According to him, when IRS was added to the TR4(A), the OD shift was 'mellowed' a bit to save the drivetrain. Don't know how true it is, but interesting just the same. Roger: OK, OK, I,m changing the fluid out next week....thanks! Out of curiousity, I did email Redline to see what the 'official' recommendation is. I sell Redline at work, and after reading the labels, decided the MTL was my best shot. I guess it might be better than 20/50?? and learn.

Rod Nichols

Rod , My TR6 lives again, supercharged !!
There are glitches to overcome, but it sounds great and the overdrive again shifts quickly , not the two second delay. Because I did more than one thing to the overdrive I don't know which was the "reason". And, I've barely driven the car, so I'm not singin from any rooftops yet. When I used the word 'snap' it was a description of speed not mechanical banging -- the shift into overdrive is very smooth. Now I have to get back to the garage, I'm chasing a vacuum leak and the car seems to want to overheat -- both rather undesirable with a brand new engine. When I've sorted it out I'll start a new thread describing my experience.
David Johnston

Rod - ditto for David's description of the o/d shift.

David - A s/c TR sounds like a lot of fun - I'm looking forward reading about it.

Have you thought about a lower diff ratio? PI's have 3.45:1 rather than the 3.7:1 of the carby models. The extra torque in the s/c would be a blast - nice long gear changes.
Roger H

This thread was discussed between 16/06/2004 and 23/06/2004

Triumph TR6 index