Rebuilding vs. replacing high mile Allison 1000 transmissions

[Mark Rinker]

I will soon be replacing the engine in my 2001. At that time, it makes sense to me to either rebuild or replace the Allison attached to it, since it will have nearly 200K miles. The transfer case will also be replaced or rebuilt at this time, as it has the classic leak and the same miles - many in 4HI plowing snow in a repeative, backward and forward manner.

Any experiences with cost and effectiveness of simple rebuilds vs. replacements appreciated. I have seen rebuild kits for sale, but wonder if this really addresses all the internal wear points?

[77TransAm]

Mark, there are REALLY going to be a lot of factors to consider when you decide which route to go. Is cost a consideration? What about down time on the truck? Skill or experience at the rebuild (these transmissions are very simple inside, so that's probably not a big issue)? Would you get the rebuild from an aftermarket company, or would you get an Allison re-trans? What components come in the rebuild kits you are considering?

There were numerous production improvements as the years went by, so there is some merit to getting a newer unit. On the other hand, if nothing has physically failed on your current trans, then you know you've got a good unit, hardware-wise.

I've torn down everything from brand new units with less than 100 miles on them that we had cooked solid, to 280,000+ mile units that I could still read the ink stamps on the clutch plates.

Personally, I get some enjoyment and satisfaction out of rebuilding and then driving one, but there are a lot of other factors to be considered.....

[Kennedy]

There's really not a lot to go wrong. In fact, probably the best thing that you could do is add a Suncoast kit like the stage III or IV. So long as there's no major pump, bearing or gear wear (unlikely but 77TA could know better) you should be good to go. Not sure how the pistons live, but Suncoast modifies and reuses them frequently. Clutches and steel seem to be all that gives grief...

P.S. Put head gaskets in your 2001 engine and go another 200k. So long as you haven't been putting any coolant in the oil (should do analysis) you should be fine.

[MaxACL]

Mark,

I saw an advertisement for Jasper engine rebuilds (Western IN). Ever heard of them?

Mike

[Mark Rinker]

The only indication that the transmission may be due for a rebuild is that it now runs about 20 degrees warmer than it used to under loaded, towing conditions. Unloaded is just the same.

Its consistantly 30-40 degrees warmer than the 2002 as well, under the same size loads. However, it should be mentioned that the 2002 had the radiator pulled and professionally tanked and cleaned last fall, which lowered BOTH water temps and tranny temps - something that anyone with 150K or better mileage should consider doing, IMO.

Both of the 2001 and 2002 trucks water and tranny temps were identical last summer. You'd never notice a difference one day to the next, switching trucks carrying similar 10-12K flatbed loads of steel.

No slippage or erratic behavior can be detected, but this trans has been pulled heavy and regularly at 340-360hp settings - its only logical to rebuild if the truck will be down and getting a new transfer case at that time as well, the other is leaking and I've opted to top it off weekly until the whole project is underway.

(Since summer is close - I may turn this truck up and pull it in a few local truck pulls with the worn componants - that way if anything breaks its getting repaired or replaced anyhow. :) )

[77TransAm]

I'll agree with Kennedy that there's not a lot to go wrong. Most of the hard parts (pistons, planetaries, shafts, etc.) will last virtually forever. I have no experience with aftermarket rebuilt kits, but on most rebuilds you'll be fine with seals and gaskets.

Some of the production changes worth incorporating in a rebuild might be the coated pump bushing and wear plate, but again; if your parts are not excessively worn or failed to this point, why upgrade? You've already got a proven unit. Throw some new seals and clutches in it, and you should be good to go for another quarter million miles.

On just a routine rebuild, that's often what I did, although I always measured all of the bushings and wear points to ensure they were within spec. I'll go out on a limb and say that as long as you have the capability to make all of the measurements called out in the service manual, you're very likely to find that just a basic seal & gasket kit and new set of clutches will do it for you.

Unfortunately the converter lockup clutch can not be accessed for measurement on little Allisons, but this is probably a good time for a converter upgrade, anyway.

[MaxACL]

How about Jasper Engines? Anyone heard of them?

Mike

[carco]

Yes, Jasper does very good work and warrants their work parts and labor. Jasper uses a lot of new parts and machines to latest OEM specs, if there is an update. Jasper sells all used engine head valves to other rebuilders and uses new valves for one example. Good people to work with for warranty problems or just to help figure out a problem even if not their reman. Jasper has a lower percent warranty defect rate than new OEM. bob..........