Allison Transmission Questions

[Bush70]

Allison Transmission Questions

Hi AllisomMAn,
I want to thank you for getting back to me. This is a great service you do for everyone.
I looked at the pin and it seems fine. Just to be sure, The cable connects to the linkage and to a box in the freme. I assume the box is the TPS correct? Any other suggestions? Also, could this take care of all the problems even the flashing d and r and not going to gear?

 

[sepisllib]

Allison Transmission Questions

Allison Man - I really appreciate having someone like you to bounce things off on this forum.

Lengthy question - please!

Bought our 93 Tourmaster with the 8.3 250 hp diesel and 3060 allison. Drove it from the lot and within a mile had to slow. Downshifting was Terrible. I thought it was going to tear the differential out it shifted so hard.

Later found that the unit was in an estate and sat for nearly 18 months.

Drove it for about 200 miles and it gradually got better with each slow down.

Now - 1200 miles later it is working well most of the time - but when it sits for more than a week the downshift from 3rd to 2nd and then 2nd to 1st it really does this hard for the first few times.

I am getting it serviced and asked them to change the transmission fluid if they can as I have not the slightest idea of how many miles are on it.

Also - the transmission temperature gauge does not function - where on the transmission is this sensor located?

Sorry for so much details - but I would enjoy knowing all I can about this unit. I will include a photo of it for your info.

Thank you in advance. Bill & Judy.

 

[Trader4Less]

Allison Transmission Questions

Allison Man,
Thank you for supporting us! I hope you don't get too overwhelmed with too many questions!

Manny

 

[93vectra]

Allison Transmission Questions

Hello alisonman, I have a 93 vectra with a md3060 6 speed allison transmission, the transmission is shifting down hard, when it hits 1st gear it is a very hard downshift, accerating the shifts seem to be sliping and reving to 2500-2600 then enageing solid to the next higher gear,
I held both arrows down on the shift pad and I get the first seq, D 1 then, 2 1 then, 1 2 flash, then repeated. what do these codes mean?
is there a shift modulator bad?
thanks for your help!

 

[psotama]

Allison Transmission Questions

AllisonMan -

I have an '87 AT-545 transmission that has been acting up. The transimission shift fine from 1 to 2 to 3, the problem is that it will not shift into top (4th) gear. As engine rpm approaches the ~3100 rpm shift point for going from 3-4, the transmission appears to attempt a shift to 4th, yet the vehicle simply "surges/lurches" as the engine rpm drops then speeds up after the failed attempt. This surging and lurching will continue as long as the throttle is held at 100% (aka, ~3100 rpm).

There doesn't appear to be any leaks and the oil level is okay. Could I have a bad seal in the control valve? Bad 4th clutch?

Any input that you might have is greatly appreciated. Thanks in advance!

Matt

 

[AllisonMan]

Allison Transmission Questions

Hi Bush70,
The flashing D and R when you put it in gear means the ECU thinks you are giving it a throttle signal of over 9% or your engine rpm is actually over 900 rpm. This is a feature so the trans will not go into gear while you have rpms up so as to not damage the drivetrain. I still suspect a bad tps or wiring for the tps. An Allison distributor or dealer can tell you just by hooking up there MPSI reader or DOC on their laptop. Thanks and have a great day!

 

[AllisonMan]

Allison Transmission Questions

Hello sepisllib,
First, make sure your battery cables are totally clean of any corrosion. If there is any sign of corrosion, this is probably the problem of the harsh downshifts, if not, have your tps check out.
The temp sender is not an Allison part but an OEM part. It will be located in a fitting for your to cooler circuit, or it should be. To test if it is the sender, ground wire and turn on ignition. If your gauge pegs to the hottest mark, it is a bad sender. If the peg doesn't move on your gauge, it is the gauge or the wiring.
Thank you for the questions and have a great day! P.S. What a gorgeouse motorhome, you sure it is a 93? Looks new. Have fun in it!

 

[AllisonMan]

Allison Transmission Questions

HelloTrader4less,
Sometimes I'm slow to answer but I try my best. Thank you for your nice words and have a great day!

 

[AllisonMan]

Allison Transmission Questions

93Vectra,
I bet you definatly have a disconnected TPS at your engine throttle lever. The code means TPS counts are too low (disconnected) and this makes the signal fail to 100% throttle. You should have the tps check out soon and I am sure it will cure your problems! Thanks and have a great day!

 

[AllisonMan]

Allison Transmission Questions

psotama,
Do you have good reverse? 4th clutch is used in reverse. Does your backup beeper still work? If not then you probably have low main pressure and you will need to have your transmission rebuilt or swapped. One other problem you could have is a broken 4th clutch trimmer spring. This also should show up as slipping in reverse. Good luck.

 

[Bush70]

Allison Transmission Questions

AllisonMan,
Thank you very much for that information. I will check the wiring and if nothing shows I will take it to Allison and have it checked. Atleast now I have an idea as to where it could be. I have worked on trucks for years but you can't be an expert in all fields. What you do on this forum is a great service. I can't thank you enough. I do a lot of work on Motorhomes also as quite a few of my friends have them. With all the electronics today you just can't check things like we use to. I will let you know how I make out. It may not be until spring as I live in the northeast and the Coach is put away right know. Again, thanks very much!!

 

[sepisllib]

Allison Transmission Questions

Allisonman - Thank you for the reply and info on the temp sender. Will work on that part.

As far as the transmission downshifting hard - I replaced both engine batteries and coach batteries and replaced the jumper cables on both with new ones. I cleaned the cable ends very thorougherly and am sure that is not the problem.

Did drive it to Minneaplolis and back yesterday (340 miles) - and again sometimes it downshifted hard from 3rd to 2nd and sometimes it did not.

It now has nearly 1600 miles on it since we bought the unit and it seems to be getting better over time and miles.

I don't drive hard - and I slow down in anticipation of lights and stop signs. Shifting from 6th to 5th, 5th to 4th is smooth and kind of hard to detect. Shifting from 4th to 3rd sometimes is a little hard - but usually not. It comes and goes. 3rd to 2nd is hard more than any other shift. Never from 2nd to 1st.

Yes - the unit is a 1993 Gulfstream Tourmaster with the 8.3 Cummings 250 hp. It runs out very smoothly and will run 70 - 75 on interstate easily still giving 8 or better for mileage.

We bought the unit as a step toward retirement - but are liking the layout so well we are talking to keeping it for our retirement entirely - that may be 2 or 3 years or if we are lucky 10 years. But it only has 72000 miles.

I would appreciate any other thoughts on the shifting --- change trans fluids -- additive (hate those things) - service by an Allison shop - etc.

Thank you again. Bill & Judy

 

[zgrasshopper]

Allison Transmission Questions

Allison MAN

Thanks for all the information. I read the first 10 pages and then gave up. So here is my question. I have a 2000 model GV320 Foretravel with a 450 cummins and a 4000 series trany with a retarder. I have a Trany Temp gauge on dash and it jumps up whenever I use the retarder. I have dextron fluid in trany, What is a SAFE temp to allow gauge to go to before switching to the brakes. The gauge reads all the way to 350. In normal driving runs around 170. Since I have the retarder should I switch to the new fluid?
Unit has 40000 mile on it. Just changed the fluid at 30,000 miles.


Thanks :laugh:

zgarsshopper
2000 foretravel GV320

 

[John Simmons]

Allison Transmission Questions

Hi , I am considering putting in an trans cooler. I have found a B$W and a Deral. Both have heavy duty ratings. The NPT connections are 1/2"... The hose coming out of the trans is 5/8", will these coolers connect up without any reduction. Is that 5/8 hose really a 1/2" fitting? :question:
P.S Do you have a recommendation for a cooler. The ones I am looking at have a fan with them
Thanks

 

[93vectra]

Allison Transmission Questions

Thanks, Allison man, The TPS linkage cable was diconnected at the throttle linkage, After I made a replacement linkage part, the transmission shifts great again, thanks for saving me time and money!
93Vectra.

 

[AllisonMan]

Allison Transmission Questions

zgrasshopper,
I would definatly convert to synthetic TES295 spec transmission fluid. Castrol Transynde is what we use but there are a few other options check out allisontransmission.com.
You should not go over 230 degrees and if you do, you will get a check transmission light on. If you reach 260 you will get shift inhibits. When the retarder is on, you are using a hydralic stator that is being slowed by oil which creates the heat so fast. I would get the oil changed over soon because at those temps with DexronIII, the viscosity breaks down much quicker than normal. If you have no codes in your transmission ECU, I would have the temp sender checked, but if you do have codes for overheat, change oil and make sure dealer or distrubutor clears the codes.
Thanks and have a great day!

 

[AllisonMan]

Allison Transmission Questions

John Simmons,
I need to know what model transmission you have before I can let you know if the holes are the right size. I will check back. Thanks and have a great day.

 

[sepisllib]

Allison Transmission Questions

Problems yet!

As I noted earlier - my transmission still shifts down really hard (not all the time) from 4th to 3rd and 3rd to 2nd. Usually in the first 100 miles or so.

Batteries were all changed (all 4) - and I made absolutely certain that terminals were all clean and I replaced the 4 jumpers with new ones.

The unit sat for 18 months - at least - before I got it. For the first 100 miles it shifted down hard on all downshifts.

Now - after nearly 2000 miles the only gears shifting down hard is the ones I mentioned above.

Thoughts and input would be appreciated.

Bill & Judy

 

[Bush70]

Allison Transmission Questions

Did you have the TPS checked out? Could be the problem.

 

[John Simmons]

Allison Transmission Questions

Hi Allisonman, The trans is an MD 3060. Also would it be ok just to run an add on cooler only and eliminate the radiator cooler. My coach weighs in at about 24000lb
Thanks John